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pdfDocument Accession #: 20231215-5332
Filed Date: 12/15/2023
UNITED STATES OF AMERICA
BEFORE THE
FEDERAL ENERGY REGULATORY COMMISSION
North American Electric Reliability Corporation
)
)
Docket No. _______
JOINT PETITION OF THE
NORTH AMERICAN ELECTRIC RELIABILITY CORPORATION AND
WESTERN ELECTRICITY COORDINATING COUNCIL FOR APPROVAL OF
PROPOSED REGIONAL RELIABILITY STANDARD VAR-501-WECC-4
Chris Albrecht
Assistant General Counsel
Western Electricity Coordinating Council
155 North 400 West, Suite 200
Salt Lake City, UT 84103
(801) 582-0353
calbrecht@wecc.org
Counsel for the Western Electricity
Coordinating Council
Lauren Perotti
Assistant General Counsel
Alain Rigaud
Associate Counsel
North American Electric Reliability
Corporation
1401 H Street NW, Suite 410
Washington, D.C. 20005
202-400-3000
lauren.perotti@nerc.net
alain.rigaud@nerc.net
Counsel for the North American Electric
Reliability Corporation
December 15, 2023
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
TABLE OF CONTENTS
I.
SUMMARY ............................................................................................................................ 2
II. NOTICES AND COMMUNICATIONS ................................................................................ 3
III. BACKGROUND .................................................................................................................... 3
a. Regulatory Framework ........................................................................................................ 4
b. WECC Reliability Standards Development Procedure........................................................ 5
c. Need for a Power System Stabilizer Standard in the Western Interconnection ................... 6
d. Development of the Proposed Reliability Standard ............................................................. 8
IV. JUSTIFICATION FOR APPROVAL .................................................................................... 8
a. Summary of Modifications .................................................................................................. 9
b. Enforceability of Proposed Regional Reliability Standard ................................................ 10
V. EFFECTIVE DATE .............................................................................................................. 11
VI. CONCLUSION ..................................................................................................................... 12
Exhibit
A-1
Exhibit
A-2
Exhibit B
Exhibit C
Proposed Regional Reliability Standard, VAR-501-WECC-4 – Power System
Stabilizer (Redline)
Proposed Regional Reliability Standard, VAR-501-WECC-4 – Power System
Stabilize (Clean)
Summary of Development History and Complete Record of Development
Standard Drafting Team Roster for Project WECC-0148 Power System Stabilizer
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Document Accession #: 20231215-5332
Filed Date: 12/15/2023
UNITED STATES OF AMERICA
BEFORE THE
FEDERAL ENERGY REGULATORY COMMISSION
North American Electric Reliability Corporation
)
)
Docket No. _______
JOINT PETITION OF THE
NORTH AMERICAN ELECTRIC RELIABILITY CORPORATION AND
WESTERN ELECTRICITY COORDINATING COUNCIL FOR APPROVAL OF
PROPOSED REGIONAL RELIABILITY STANDARD VAR-501-WECC-4
Pursuant to Section 215(d)(1) of the Federal Power Act (“FPA”)1 and Section 39.5 of the
regulations of the Federal Energy Regulatory Commission (“FERC” or “Commission”),2 the North
American Electric Reliability Corporation (“NERC”)3 and the Western Electricity Coordinating
Council (“WECC”) hereby submit proposed Regional Reliability Standard VAR-501-WECC-4 –
Power System Stabilizer for Commission approval (“Joint Petition”). Proposed Regional
Reliability Standard VAR-501-WECC-4 establishes the performance criteria for power system
stabilizers to help ensure the Western Interconnection is operated in a coordinated manner under
normal and abnormal conditions. NERC requests that the Commission approve proposed Regional
Reliability Standard VAR-501-WECC-4 (Exhibit A) and find that the proposed Regional
Reliability Standard is just, reasonable, not unduly discriminatory or preferential, and in the public
interest.
NERC also requests approval of the associated elements, including the effective date and
the Violation Risk Factors and Violation Severity Levels (which are unchanged from the currently
1
16 U.S.C. § 824o.
18 C.F.R. § 39.5 (2023).
3
The Commission certified NERC as the electric reliability organization (“ERO”) in accordance with
Section 215 of the FPA. N. Am. Elec. Reliability Corp., 116 FERC ¶ 61,062 (2006) [hereinafter ERO Certification
Order].
2
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effective standard) (Exhibit A), and the retirement of currently-effective Regional Reliability
Standard VAR-501-WECC-3.1.
As required by Section 39.5(a) of the Commission’s regulations,4 this petition presents the
technical basis and purpose of the proposed Regional Reliability Standard, and a summary of the
development history (Exhibit B). The proposed Regional Reliability Standard continues to meet
the criteria for Commission approval as set forth in Order No. 672 as demonstrated in the last
major revision.5 The NERC Board of Trustees adopted the proposed Regional Reliability Standard
on December 12, 2023.
I.
SUMMARY
Power system stabilizers damp oscillations that can occur between geographic areas within
the Western Interconnection and play an important role in the stability of the Western
Interconnection. Over the past several decades, WECC and related working groups have developed
policies and guidelines, conducted studies, and approved a Regional Reliability Standard to help
manage power system stabilizer use within the Western Interconnection. With the development of
proposed Regional Reliability Standard VAR-501-WECC-4, WECC seeks to make NonSubstantive Changes6 as a part of a five-year review of the currently effective Regional Reliability
Standard VAR-501-WECC-3.1.
The purpose of proposed Regional Reliability Standard VAR-501-WECC-4 is to ensure
the Western Interconnection is operated in a coordinated manner under normal and abnormal
4
18 C.F.R. § 39.5(a).
Rules Concerning Certification of the Electric Reliability Organization; and Procedures for the
Establishment, Approval, and Enforcement of Electric Reliability Standards, Order No. 672, 114 FERC ¶ 61,104,
order on reh’g, Order No. 672-A, 114 FERC ¶ 61,328 (2006) [hereinafter Order No. 672].
6
Under WECC’s regional standards development procedure, “Non-Substantive Changes” are revisions that
do not change the scope, applicability, or intent of any requirement, including correcting the numbering of a
requirement, correcting references, changes to document styles and templates, correcting the spelling of a word,
adding an obviously missing word, or rephrasing a requirement for improved clarity. See infra n. 25.
5
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conditions by establishing the performance criteria f or power system stabilizers. Proposed
Regional Reliability Standard VAR-501-WECC-4 improves upon the existing standard by (1)
updating the document template, numbering, and template sections as provided by NERC, (2)
removing antiquated language from the Effective Date, removing redundant language from
Measure M4, (3) updating syntax, and (4) correcting language such as “[s]tandard” to “[S]tandard”
and from “dampen” to “damp” in the Rationale and Guidance section. These changes will improve
the readability of the Regional Reliability Standard.
In this Joint Petition, NERC and WECC respectfully request the Commission approve
proposed Regional Reliability Standard VAR-501-WECC-4, the associated VRFs and VSLs, and
the retirement of the existing Regional Reliability Standard VAR-501-WECC-3.1. The following
Joint Petition presents the justification for approval and supporting documentation.
II.
NOTICES AND COMMUNICATIONS
Notices and communications with respect to this filing may be addressed to the following:7
Chris Albrecht*
Assistant General Counsel
Steven Rueckert*
Director of Standards
Western Electricity Coordinating Council
155 North 400 West, Suite 200
Salt Lake City, UT 84103
(801) 582-0353
calbrecht@wecc.org
srueckert@wecc.org
III.
Lauren Perotti*
Assistant General Counsel
Alain Rigaud*
Associate Counsel
North American Electric Reliability
Corporation
1401 H Street, N.W., Suite 410
Washington, D.C. 20005
(202) 400-3000
lauren.perotti@nerc.net
alain.rigaud@nerc.net
BACKGROUND
The following background information is provided below: (1) an explanation of the
regulatory framework for NERC; (2) a description of the WECC Regional Reliability Standards
7
NERC respectfully requests a waiver of Rule 203 of the Commission’s regulations, 18 C.F.R. § 385.203
(2023), to allow the inclusion of more than two persons on the service list in this proceeding.
3
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Development Procedure; (3) a discussion of the need for power system stabilizers in the Western
Interconnection; and (4) the history of Project WECC-0148 VAR-501-WECC-4 Power System
Stabilizer, Five-year Review.
a. Regulatory Framework
By enacting the Energy Policy Act of 2005,8 Congress entrusted the Commission with the
duties of approving and enforcing rules to ensure the reliability of the Bulk-Power System, and
with the duty of certifying an ERO that would be charged with developing and enforcing
mandatory Reliability Standards, subject to Commission approval. Section 215(b)(1) of the FPA
states that all users, owners, and operators of the Bulk-Power System in the United States will be
subject to Commission-approved Reliability Standards.9 Section 215(d)(5) of the FPA authorizes
the Commission to order the ERO to submit a new or modified Reliability Standard.10 Section
39.5(a) of the Commission’s regulations requires the ERO to file for Commission approval each
Reliability Standard that the ERO proposes should become mandatory and enforceable in the
United States, and each modification to a Reliability Standard that the ERO proposes to make
effective.11
The Commission has the regulatory responsibility to approve Reliability Standards that
protect the reliability of the Bulk-Power System and to ensure that such Reliability Standards are
just, reasonable, not unduly discriminatory or preferential, and in the public interest. Pursuant to
Section 215(d)(2) of the FPA and Section 39.5(c) of the Commission’s regulations, the
8
9
10
11
16 U.S.C. § 824o.
Id. § 824o(b)(1).
Id. § 824o(d)(5).
18 C.F.R. § 39.5(a).
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Commission will give due weight to the technical expertise of the ERO with respect to the content
of a Reliability Standard.12
Similarly, the Commission approves regional differences proposed by Regional Entities,
such as Regional Reliability Standards and Variances, if the regional difference is just, reasonable,
not unduly discriminatory or preferential, and in the public interest.13 In addition, Commission
Order No. 672 requires further criteria for regional differences. A regional difference from a
continent-wide Reliability Standard must either be: (1) more stringent than the continent-wide
Reliability Standard, including a regional difference that addresses matters that the continent-wide
Reliability Standard does not; or (2) necessitated by a physical difference in the Bulk-Power
System.14 The Commission must give due weight to the technical expertise of a Regional Entity,
like WECC, that is organized on an Interconnection-wide basis, with respect to a regional
difference to be applicable within that Interconnection.15
b. WECC Reliability Standards Development Procedure
The proposed Regional Reliability Standard was developed in an open and fair manner and
in accordance with the Commission-approved WECC Reliability Standards Development
Procedures (“RSDP”).16 WECC’s RSDP provides for reasonable notice and opportunity for public
comment, due process, openness, and a balance of interests in developing Reliability Standards
and thus addresses several of the Commission’s criteria for approving Reliability Standards. The
12
16 U.S.C. § 824o(d)(2); 18 C.F.R. § 39.5(c)(1).
16 U.S.C. § 824o(d)(2); 18 C.F.R. § 39.5(a).
14
Order No. 672 at P 291.
15
Id. at P 344.
16
The currently effective WECC RSDP was approved by the Commission on September 13, 2021 See N. Am.
Elec. Reliability Corp., Docket No. RR21-4-000 (Sept. 13, 2021) (approving revised WECC Reliability Standards
Development Procedures) [hereinafter WECC RSDP]. The WECC Reliability Standards Development Procedures
are available at:
https://www.wecc.org/Reliability/WECC%20Reliability%20Standards%20Development%20Procedures%20%20FERC%20Approved%2009-13-2021.pdf.
13
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development process is open to any person or entity that is an interested stakeholder. WECC
considers the comments of all stakeholders, and a vote of stakeholders and the WECC Board of
Directors is required to approve a WECC Regional Reliability Standard. 17 NERC posts each
regional Variance developed by a Regional Entity for an additional comment period. The NERC
Board of Trustees must adopt the regional Variance before it is submitted to the Commission for
approval.
c. Need for a Power System Stabilizer Standard in the Western Interconnection
As NERC and WECC noted in previous filings, 18 power system stabilizers play an
important role in the stability of the Western Interconnection. Power system stabilizers are part of
the automatic voltage regulation system of a generator and are designed to add or subtract torque
to a generator with the goal of damping oscillations on the Western Interconnection’s Bulk Electric
System (“BES”) that otherwise would be amplified if the automatic voltage regulator is operated
alone. Power system stabilizers within WECC were developed in the 1960s in response to power
system oscillations on the Pacific Intertie within the Western Interconnection. These oscillations
occur at very low frequencies (<1 Hertz), are very lightly dampened, and became known as “interarea modes” of oscillation because they occur when real power is transferred from one Western
Interconnection geographic region to another (such as between the Pacific Northwest and the
Southwest). These modal oscillations are the result of a combination of many machines on one
part of the Western Interconnection BES whose voltage support response to system fluctuations is
not in phase with the response of machines on another part of the Western Interconnection BES.
17
Id. at 12, Treatment of Non-Substantive Changes (providing that approval by the WECC Board of
Directors is not required when the WECC Standards Committee has approved the Non-Substantive Changes, which
is the case for proposed Regional Reliability Standard VAR-501-WECC-4).
18
NERC, Joint Petition of the North American Electric Reliability Corporation and Western Electricity
Coordinating Council for Approval of Proposed Regional Reliability Standard VAR-501-WECC-3, Docket No.
RD17-5-000 (March 10, 2017).
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Moreover, as the Commission recognized, the Western Interconnection possesses
particular physical characteristics that justify interconnection-specific requirements.19 In Order
No. 740, the Commission stated:
[I]n the Western Interconnection a significant number of
transmission paths are voltage or frequency stability-limited, in
contrast to other regions of the [BES] where transmission paths
more often are thermally-limited. Disturbances resulting in a
stability-limited transmission path overload, generally, must be
responded to in a shorter time frame than a disturbance that results
in a thermally-limited transmission path overload. [FERC has also
noted] its understanding that this physical difference is one of the
reasons for the need for certain provisions of Regional Reliability
Standards in the Western Interconnection.20
As a result of the Western Interconnection physical characteristics, WECC developed a
Regional Reliability Standard, policies, and guidelines that address power system stabilizers.
Proposed Regional Reliability Standard VAR-501-WECC-4 will continue to address the unique
characteristics of the Western Interconnection in one set of requirements that incorporate WECC’s
long history with power system stabilizers, consistent with the currently effective version of the
Regional Reliability Standard.
The Commission approved the last major revision VAR-501-WECC-3, in 2017.21 Shortly
thereafter in 2017, the Commission approved the currently effective version, VAR-501-WECC3.1, which reflected an erratum in the VSL by replacing the term “Transmission Planner” with
“Transmission Operator”.22
19
Version One Regional Reliability Standard for Resource and Demand Balancing, Order No. 740, 133
FERC ¶ 61,063 at P 23 (2010).
20
Id.
21
N. Am. Elec. Reliability Corp., Docket No. RD17-5-000 (April 28, 2017) (delegated letter order approving
VAR-501-WECC-3).
22
N. Am. Elec. Reliability Corp., Docket No. RD17-7-000 (Sep. 26, 2017) (delegated letter order approving
errata to Voltage and Reactive Control Reliability Standards).
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d. Development of the Proposed Reliability Standard
As further described in Exhibit B hereto, proposed Regional Reliability Standard VAR501-WECC-4 was developed as part of a five-year review of the currently effective Regional
Reliability Standard in accordance with the WECC RSDP. 23 The project was titled, Project
WECC-0148 VAR-501-WECC-4 Power System Stabilizer, Five-year Review. On July 1, 2022,
the drafting team unanimously agreed that there would be no Substantive Changes 24 to the
proposed Regional Reliability Standard, and on July 16, 2022, posted a list of Non-Substantive
Changes.25 The WECC Standards Committee (“WSC”) approved the Non-Substantive Changes
on December 6, 2022.26 NERC posted the standard for a 45-day comment period from August 16,
2023 through September 29, 2023. Commenters expressed no concerns regarding the proposed
Regional Reliability Standard.
The NERC Board of Trustees adopted the proposed Regional Reliability Standard on
December 12, 2023.
IV.
JUSTIFICATION FOR APPROVAL
Approval of proposed Regional Reliability Standard VAR-501- WECC-4 – Power System
Stabilizer is just, reasonable, not unduly discriminatory or preferential, and in the public interest.
As described more fully herein, the VAR-501-WECC Regional Reliability Standard provides
23
WECC RSDP at 21.
Id. at 3. (“Substantive Change: A change that alters the scope, applicability, required actions, or intent of
the document.”).
25
See e.g. Id. at 3 (“Non-Substantive Change: Revisions that do not change the scope, applicability, or intent
of any requirement, including correcting the numbering of a requirement, correcting references, changes to
document styles and templates, correcting the spelling of a word, adding an obviously missing word, or rephrasing a
requirement for improved clarity.”); see also Id. at 12 (“Non-Substantive Changes do not require a
posting/comment/response cycle.”)
26
Id. at 12. (“If a Non-Substantive Change to an RRS is required at any time after a WECC ballot window
opens, the proposed change shall be presented to the WSC with a request for approval. If the WSC agrees that the
correction of the error does not change the scope or intent of the associated RRS, and agrees that the correction has
no material impact on the applicable entities, then the correction shall be filed for approval with NERC and
applicable governmental authorities as appropriate.”).
24
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reliability benefits for the Bulk-Power System in the WECC region. The purpose of proposed
Regional Reliability Standard VAR-501-WECC-4, like the currently effective version, is to ensure
the Western Interconnection is operated in a coordinated manner under normal and abnormal
conditions by establishing the performance criteria for power system stabilizers. Consistent with
the currently effective version, the provisions of the proposed standard would continue to provide
mandatory performance requirements for power system stabilizers in the Western Interconnection
based on long-held policy in the WECC region.
This section of the petition discusses the Non-Substantive modifications reflected in
proposed Regional Reliability Standard VAR-501-WECC-4 which improve the readability of the
standard.
a. Summary of Modifications
The proposed Regional Reliability Standard VAR-501-WECC-4 was developed as part of
a five-year review of currently effective Regional Reliability Standard VAR-501-WECC-3.1.
The proposed Regional Reliability Standard VAR-501-WECC-4 revisions were deemed as NonSubstantive Changes and, under WECC’s RSDP, were approved by the WSC.
The standard would continue to be applicable to (1) Generator Operators in the Western
Interconnection that operate synchronous generators, connected to the BES, that meet the
definition of Commercial Operation; and (2) Generator Owners in the Western Interconnection
that own synchronous generators, connected to the BES, that meet the definition of Commercial
Operation.27
27
“Commercial Operation” is a WECC Regional Term and is defined as “[a]chievement of this designation
indicates that the Generator Operator or Transmission Operator of the synchronous generator or synchronous
condenser has received all approvals necessary for operation after completion of initial start-up testing.” Glossary of
Terms Used in NERC Reliability Standards, available at
https://www.nerc.com/pa/Stand/Glossary%20of%20Terms/Glossary_of_Terms.pdf.
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The Non-Substantive Changes to the Proposed Regional Reliability Standards are:
1. Updates to the document template, numbering, and template sections as provided
by NERC,
2. Removal of antiquated language from Effective Date, removal of redundant
language from Measure M4,
3. Updates to syntax, and
4. Correction of language such as “[s]tandard” to [S]tandard” and from “dampen” to
“damp” in the Rationale and Guidance section.
The proposed changes are shown in redline in Exhibit A-1. The proposed changes show
a five-year review of the Regional Reliability standard occurred in compliance with the WECC
RSDP, and will improve readability by modernizing the template and removing redundant and
outdated language. No Substantive changes to the Regional Reliability Standard are proposed.
b. Enforceability of Proposed Regional Reliability Standard
The proposed Regional Reliability Standard includes VRFs and VSLs. The VRFs and
VSLs provide guidance on the way that NERC will enforce the requirements of the proposed
Reliability Standard. The VRFs and VSLs are substantively unchanged from the currently effective
version of the Regional Reliability Standard. As such, they continue to comport with NERC and
Commission guidelines related to their assignment.
In addition, the proposed Regional Reliability Standard also includes measures that support
each requirement by clearly identifying what is required and how the ERO will enforce the
requirement. These measures help ensure that the requirements will be enforced in a clear,
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consistent, and non-preferential manner and without prejudice to any party.28 The measures are
substantively unchanged from the currently effective version of the Regional Reliability Standard.
V.
EFFECTIVE DATE
NERC respectfully requests that the Commission approve the proposed Regional
Reliability Standard to become effective on the first day of the first calendar quarter following
regulatory approval of the proposed Regional Reliability Standard. The proposed effective date is
consistent with ERO Enterprise practice to have new versions of Reliability Standards become
effective on the first day of a first calendar quarter for administrative efficiency.
28
Order No. 672 at P 327.
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VI.
Filed Date: 12/15/2023
CONCLUSION
For the reasons set forth above, NERC respectfully requests that the Commission approve:
Proposed Regional Reliability Standard VAR-501-WECC-4, and associated elements
included in Exhibit A, effective as proposed herein.
The retirement of Regional Reliability Standard VAR-501-WECC-3.1 effective as
proposed herein.
Respectfully submitted,
/s/ Alain Rigaud
Chris Albrecht
Legal Counsel
Western Electricity Coordinating Council
155 North 400 West, Suite 200
Salt Lake City, UT 84103
(801) 582-0353
calbrecht@wecc.org
Counsel for the Western Electricity
Coordinating Council
Lauren Perotti
Assistant General Counsel
Alain Rigaud
Associate Counsel
North American Electric Reliability Corporation
1401 H Street, N.W., Suite 410
Washington, D.C. 20005
(202) 400-3000
lauren.perotti@nerc.net
alain.rigaud@nerc.net
Counsel for the North American Electric Reliability
Corporation
Date: December 15, 2023
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Exhibit A
Proposed Regional Reliability Standard
VAR-501-WECC-4 – Power System Stabilizer
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Exhibit A-1
Proposed Regional Reliability Standard
VAR-501-WECC-4 – Power System Stabilizer
(Redline)
Document Accession #: 20231215-5332
Date: 12/15/2023
Filed
VAR‐501‐WECC‐43.1 – Power System Stabilizer
A. A.
Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR‐501‐WECC‐3.14
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1 Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, that meetmeeting the definition of Commercial Operation.
6. Effective Date: The first day of the first quarter following regulatory approval, except
for Requirement R3.
For units placed in first‐time service after regulatory approval, Requirement R3 is
effective the first day of the first quarter following final regulatory approval.
For units placed in service prior to final regulatory approval, Requirement R3 is effective
the first day of the first quarter that is five years after regulatory approval.
B.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
The effective date of this standard;
The PSS’s Commercial Operation date; or
Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
Component failure
Testing of a Bulk Electric System Element affecting or affected by the PSS
Maintenance
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter‐area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start‐up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start‐up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
For auditing purposes The first bullet of Requirement R4, bullet one only applies to
equipment on its initial (first energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
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Filed
VAR‐501‐WECC‐43.1 – Power System Stabilizer
C. Compliance
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority
: “Compliance Enforcement Authority” means NERC or the Regional Entity, or any entity
as otherwise designated by an Applicable Governmental Authority, in their
respective roles of monitoring and/or enforcing compliance with mandatory and
enforceable Reliability Standards in their respective jurisdictions.
1.2 Compliance Monitoring and Assessment Processes
Compliance Audits
Self‐Certifications
Spot Checking
Compliance Investigations
Self‐Reporting
Complaints
1.3 . Evidence Retention
: The following evidence retention periodsperiod(s) identify the period of time an entity
is required to retain specific evidence to demonstrate compliance. For instances
where the evidence retention period specified below is shorter than the time since
the last audit, the Compliance Enforcement Authority may ask an entity to provide
other evidence to show that it was compliant for the full ‐time period since the last
audit.
The applicable entity shall keep data or evidence to show compliance as identified
below unless directed by its Compliance Enforcement Authority to retain specific
evidence for a longer period of time as part of an investigation.
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.4 Additional Compliance Information
None
D. Regional Differences
None
Page 4 of 14
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Filed
VAR‐501‐WECC‐3.14 – Power System Stabilizer
Attachment DB
Table of Compliance Elements
1.3 Compliance Monitoring and Enforcement Program: As defined in the NERC Rules of
Procedure, “Compliance Monitoring and Enforcement Program” refers to the
identification of the processes that will be used to evaluate data or information for
the purpose of assessing performance or outcomes with the associated Reliability
Standard.
Page 5 of 14
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
R
Violation Severity Levels
Lower VSL
Moderate VSL
High VSL
Severe VSL
R1 NA
NA
NA
The Generator Owner failed to
provide its PSS operating
specifications to the
Transmission Operator as
required in Requirement R1.
R2 Each Generator Operator not
having its PSS in service while
synchronized in accordance with
Requirement R2, for more than 30
minutes but less than 60 minutes.
Each Generator Operator
not having its PSS in service
while synchronized in
accordance with
Requirement R2, for more
than 60 minutes but less
than 120 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 120 minutes but
less than 180 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 180 minutes.
R3 The Generator Owner’s PSS failed
to meet any of the required
performances in Requirement R3,
two times or fewer during the
audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, three times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, four times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, five times or
more during the audit period.
R4 NA
NA
NA
The Generator Owner failed to
install on its generator a PSS,
as required in Requirement R4.
R5 NA
NA
NA
The Generator Owner failed to
repair or replace a non‐
operational PSS as required in
Requirement R5.
Page 6 of 14
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Filed Date: 12/15/2023
VAR‐501‐WECC‐43.1 – Power System Stabilizer
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Page 8 of 14
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
D. Regional Variances
None.
E. Associated Documents
None.
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Change Tracking
Permanent Replacement
Standard for VAR‐STD‐002b‐1
Adopted by NERC Board of
Trustees
1
April 21, 2011
FERC Order issued approving
VAR‐
501‐WECC‐1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR‐501‐WECC‐2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR‐501‐WECC‐3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
3.1
TBDSeptember 26,
2017
TBDFERC letter order issued
approving VAR‐501‐WECC‐3.1
4
December 6, 2022
WECC Standards Committee
accepted a “no change “
recommendation followed by
Errata
Non‐substantive
changes were
approved by the
Page 9 of 14
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Date: 12/15/2023
Filed
VAR‐501‐WECC‐3.14 – Power System Stabilizer
an information‐only filing to
NERC.
WECC Standards
Committee as
allowed in the WECC
Reliability Standards
Development
Procedures. An
information‐only
filing provided to
NERC reflects the
following: 1) updates
to the template and
syntax, 2) removal of
stale‐dated language
from the Effective
Date, 3) deletion of
“For auditing
purposes of…” from
M4, 4) in the
Guidance section,
“dampen” was
replaced with
“damp”, and syntax
was addressed
deleting “still”, “of
those”, “of the”, and
“to ensure” was
replaced with
“ensuring”, and
“wash out” was
replaced with
“washout.”
Page 10 of 14
Document Accession #: 20231215-5332
Date: 12/15/2023
Filed
VAR‐501‐WECC‐3.14 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to dampendamp the low‐frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while still allowing for some of these
units to be out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either of the triggering eventsevent
described in Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non‐active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this
standardStandard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this standardStandard while also allowing the Generator Owner to create a unit‐
specific operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non‐active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator‐turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
Page 11 of 14
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this standard’sStandard’s previous version, the logged hours were totaled quarterly
to meet the 98% in‐service requirement. Instead of documenting the number of hours
excluded, this Requirement simplifies the process by allowing the Generator Operator to
communicate to the Transmission Operator the circumstances that render the PSS unavailable
to the Transmission Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function, and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable wash‐outwashout time constants, the Requirement
specifies 0.2 Hz as the applicable threshold. The 0.2 Hz threshold more closely aligns with the
observed oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher‐frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed‐loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward to ensureensuring that a unit is
tuned, Requirement R5 looks backward. Specifically, the language in Requirement R5,
“becoming incapable,” indicates the unit was previously capable of meeting the tuning
requirements in Requirement R3, but is no longer capable. Restated, Requirement R5 addresses
units that were previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24‐month time frame is sufficient to return a functional, operating PSS to service.
Page 13 of 14
Document Accession #: 20231215-5332
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Filed
VAR‐501‐WECC‐3.14 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR‐501‐WECC‐3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
VAR‐501‐WECC‐3
TBD
TBD
Inactive Date
Page 14 of 14
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Exhibit A-2
Proposed Regional Reliability Standard
VAR-501-WECC-4 – Power System Stabilizer
(Clean)
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
A. Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR-501-WECC-4
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1
Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, meeting the definition of Commercial Operation.
6. Effective Date:
The first day of the first quarter following regulatory approval.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
• The effective date of this standard;
• The PSS’s Commercial Operation date; or
• Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
•
Component failure
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VAR-501-WECC-4 – Power System Stabilizer
•
Testing of a Bulk Electric System Element affecting or affected by the PSS
•
Maintenance
•
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
•
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
•
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter-area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
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VAR-501-WECC-4 – Power System Stabilizer
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start-up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
•
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
•
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start-up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
The first bullet of Requirement R4 only applies to equipment on its initial (first
energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
Page 3 of 11
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Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority: “Compliance Enforcement Authority” means
NERC or the Regional Entity, or any entity as otherwise designated by an
Applicable Governmental Authority, in their respective roles of monitoring and/or
enforcing compliance with mandatory and enforceable Reliability Standards in
their respective jurisdictions.
1.2. Evidence Retention: The following evidence retention period(s) identify the period
of time an entity is required to retain specific evidence to demonstrate
compliance. For instances where the evidence retention period specified below is
shorter than the time since the last audit, the Compliance Enforcement Authority
may ask an entity to provide other evidence to show that it was compliant for the
full-time period since the last audit.
The applicable entity shall keep data or evidence to show compliance as identified
below unless directed by its Compliance Enforcement Authority to retain specific
evidence for a longer period of time as part of an investigation.
•
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.3 Compliance Monitoring and Enforcement Program: As defined in the NERC Rules of
Procedure, “Compliance Monitoring and Enforcement Program” refers to the
identification of the processes that will be used to evaluate data or information for
the purpose of assessing performance or outcomes with the associated Reliability
Standard.
Page 4 of 11
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VAR-501-WECC-4 – Power System Stabilizer
R
Violation Severity Levels
Lower VSL
R1
Moderate VSL
High VSL
Severe VSL
NA
NA
NA
The Generator Owner failed to
provide its PSS operating
specifications to the
Transmission Operator as
required in Requirement R1.
Each Generator Operator not
having its PSS in service while
synchronized in accordance with
Requirement R2, for more than 30
minutes but less than 60 minutes.
Each Generator Operator
not having its PSS in service
while synchronized in
accordance with
Requirement R2, for more
than 60 minutes but less
than 120 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 120 minutes but
less than 180 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 180 minutes.
The Generator Owner’s PSS failed
to meet any of the required
performances in Requirement R3,
two times or fewer during the
audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, three times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, four times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, five times or
more during the audit period.
R4
NA
NA
NA
The Generator Owner failed to
install on its generator a PSS,
as required in Requirement R4.
R5
NA
NA
NA
The Generator Owner failed to
repair or replace a nonoperational PSS as required in
Requirement R5.
R2
R3
Page 5 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
D. Regional Variances
None.
E. Associated Documents
None.
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Permanent Replacement
Standard for VAR-STD-002b-1
Adopted by NERC Board of
Trustees
1
April 21, 2011
FERC Order issued approving
VAR501-WECC-1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR-501-WECC-2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR-501-WECC-3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
3.1
September 26, 2017
FERC letter order issued
approving VAR-501-WECC-3.1
December 6, 2022
WECC Standards Committee
accepted a “no change “
recommendation followed by
4
Change Tracking
Errata
Non-substantive
changes were
approved by the
Page 6 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
an information-only filing to
NERC.
4
WECC Standards
Committee as
allowed in the WECC
Reliability Standards
Development
Procedures. An
information-only
filing provided to
NERC reflects the
following: 1) updates
to the template and
syntax, 2) removal of
stale-dated language
from the Effective
Date, 3) deletion of
“For auditing
purposes of…” from
M4, 4) in the
Guidance section,
“dampen” was
replaced with
“damp”, and syntax
was addressed
deleting “still”, “of
those”, “of the”, and
“to ensure” was
replaced with
“ensuring”, and
“wash out” was
replaced with
“washout.”
TBD
Page 7 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to damp the low-frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while allowing for some units to be
out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either triggering event described in
Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non-active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this Standard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this Standard while also allowing the Generator Owner to create a unit-specific
operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non-active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator-turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
Page 8 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this Standard’s previous version, the logged hours were totaled quarterly to meet
the 98% in-service requirement. Instead of documenting the number of hours excluded, this
Requirement simplifies the process by allowing the Generator Operator to communicate to the
Transmission Operator the circumstances that render the PSS unavailable to the Transmission
Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function, and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable washout time constants, the Requirement specifies 0.2 Hz
as the applicable threshold. The 0.2 Hz threshold more closely aligns with the observed
oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher-frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed-loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
Page 9 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward ensuring that a unit is tuned,
Requirement R5 looks backward. Specifically, the language in Requirement R5, “becoming
incapable,” indicates the unit was previously capable of meeting the tuning requirements in
Requirement R3, but is no longer capable. Restated, Requirement R5 addresses units that were
previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24-month time frame is sufficient to return a functional, operating PSS to service.
Page 10 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR-501-WECC-3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
VAR-501-WECC-3
TBD
TBD
Inactive Date
Page 11 of 11
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Exhibit B
Summary of Development History and
Complete Record of Development
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment E
Project Roadmap
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Informational Only Filing
Project Roadmap
Actions
Completed
1.
Standard Authorization Request (SAR) Filed
March 9, 2022
2.
WECC Standards Committee (WSC) approved the SAR
March 16, 2022
3.
Drafting Team (DT) Solicitation
March 30, 2022
4.
DT Meeting
June 21, 2022
5.
DT Meeting
June 28, 2022
6.
7.
8.
Notice to Standard Email List for Proposed Non‐Substantive
Changes – No Substantive Changes Proposed
Posting 1 for Information Only – Comment/Response not
Required
Posting 1 Letter to WSC for Proposed Non‐Substantive Changes
July 11, 2022
9.
WSC Approved Non‐Substantive Changes
December 6, 2022
10.
WECC Board of Directors—Approved
Not Required
11.
Informational Filing pending at NERC
TBD
12.
NERC Board of Trustees Approves
TBD
July 16, 2022
July 16, 2022
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Standard Authorization Request
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Five-year Review
Overview
This Standard Authorization Request (SAR) was received March 7, 2022, and deemed complete the
same day. The WECC Standards Committee (WSC) vetted this SAR on March 16, 2022.
This SAR can be reviewed on the WECC-0148 project page at the Standard Authorization Request
accordion. If you have questions regarding this SAR, please contact W. Shannon Black at (503) 3075782.
Introduction
This is a request for five-year review of WECC Regional Reliability Standard VAR-501-WECC-3.1
Power System Stabilizer.1
Requester Information
Primary contact
•
First name:
W. Shannon
•
Last name:
Black
•
•
Email:
Phone:
sblack@wecc.org
(503) 307-5782
•
Organization name:
Western Electricity Coordinating Council (WECC)
Alternate
•
First name:
Donovan
•
•
Last name:
Email:
Crane
dcrane@wecc.org
•
Phone:
Per the WECC Reliability Standards Procedures, Maintenance of RRSs and CRTs: ‘The WSC shall ensure that
each…RRS is reviewed at least once every five years from the effective date of the most recent version of the
document under review. If the review identifies needed changes, the WSC shall cause a remedial SAR to be filed.
If the review does not identify needed changes, no further action is required.”
1
155 N ort h 400 W est | Sui t e 200 | Sal t Lak e City , Ut ah 84103
www. wec c. or g
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Standard Authorization Request
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Five-year Review
Type of Request
This is a request for five-year review of a WECC Regional Reliability Standard.
Create, Modify, Retire or Review a Document
Requested Action (Select one)
•
This is a request for a five-year review of a WECC Regional Reliability Standard (RRS).
Document Type (Select one)
•
WECC Regional Reliability Standard
Issue
This project is assigned WECC Tracking Number WECC-0148.
This a request for a five-year review mandated per the WECC Reliability Standards Development
Procedures (Procedures).
Proposed Remedy
This request will review and update the entire document, as needed. No specific concerns have been
identified. The drafting team is authorized to recommend “no change” after reviewing the document.
Applicable Entities
Each function will be reviewed if affected. A dropdown will be provided. Check all applicable blocks.
4. Functional Entities:
4.1. Generator Operator
4.2. Generator Owner
Detailed Description
This request will review and update the entire document, as needed. No specific concerns have been
identified.
Affected Reliability Principles
•
Reliability Principle 1 — Interconnected bulk power systems shall be planned and operated in
a coordinated manner to perform reliably under normal and abnormal conditions as defined in
the NERC Standards.
2
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Standard Authorization Request
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Five-year Review
Document Information
NA
Reference Uploads
Provide Additional Comments (if needed).
NA
3
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WECC Standards Committee
Meeting Agenda
Virtual
Virtual meeting link | Dial-in Number: 1-415-655-0003, Attendee Access Code: 2456 527 7931
1.
Welcome, Call to Order—James Avery
2.
Review WECC Antitrust Policy—Steven Rueckert
WECC Antitrust Policy.
Please contact WECC legal counsel if you have any questions.
3.
Approve Agenda—James Avery
4.
Review and Approve Previous Meeting Minutes—James Avery
Approval Item: December 7, 2021, minutes
5.
Review of Previous Action Items—W. Shannon Black
Standards Voting Segment Representatives; Drafting Team Nominees; Charter and Glossary
Review
6.
Request to Approve Standard Authorization Request
WECC-0148 VAR-501-WECC-4, Power System Stabilizer, Five-year Review
7.
Request to Approve Drafting Nominations—W. Shannon Black
WECC-0146 TPL-001-WECC-CRT-4, Transmission System Planning Performance
WECC-0147 BAL-004-WECC-3, ATEC Five-year Review with Focus on Requirement R1
8.
Standard Voting Segment Criteria Application—W. Shannon Black
9.
Reports—Various
SVS 6 welcomes Tim Kelley to the WSC
10.
Action Without a Meeting—W. Shannon Black
No report
11.
Public Comment
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Agenda—March 16, 2022
12.
Review of New Action Items—W. Shannon Black
13.
Review Upcoming Meetings
To Be Determined ..................................................................................... TBD
14.
Adjourn
2
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Black, Shannon
From:
Sent:
Subject:
Black, Shannon
Wednesday, 30 March, 2022 10:50 AM
WECC-0148 VAR-501-WECC-4 Notice of Drafting Team Solicitation
WECC-0148 VAR-501-WECC-4 Power System Stabilizer – Five-year Review
Drafting Team nominations are being solicited for the following project:
• WECC-0148 VAR-501-WECC-4 Power System Stabilizer - Five-year Review
This project will complete a five-year review mandated per the WECC Reliability Standards
Development Procedures (Procedures). This request will review and update the entire
document, as needed. No specific concerns have been identified. The drafting team is
authorized to recommend “no change” after reviewing the document.
If you have an interest in participating on this drafting team, please submit a “DT
Nomination Form” found on the Standards Under Development Page. From the Tracking
Number drop down menu, please select “WECC-0148.”
Nominations will be addressed at the next scheduled WECC Standards Committee (WSC)
meeting.
W. Shannon Black, JD
WECC Consultant, Standards Processes
(503) 307-5782
sblack@wecc.org
1
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WECC-0148
VAR-501-WECC-4
Power System Stabilizer
Drafting Team Meeting Agenda
Virtual
Webinar Link | Password: WECC | Dial‐in Number: 1‐415‐655‐0003, Attendee Access Code: 2456 499 7510
June 21, 2022, 10:00 a.m. to 12:00 p.m.
1.
Welcome, Call to Order, Introductions—W. Shannon Black
2.
Review WECC Antitrust Policy—W. Shannon Black
WECC Antitrust Policy.
Please contact WECC legal counsel if you have any questions.
3.
Approve Agenda
4.
Review and Approve Previous Meeting Minutes
Approval Item: No Previous Minutes
5.
Review of Previous Action Items—W. Shannon Black
6.
Drafting—W. Shannon
Standard Authorization/Scope Review; Review of Development Principles
7.
Public Comment
8.
Review of New Action Items
9.
Review Upcoming Meetings
June 28, 2022, 10:00 a.m. to 12:00 p.m. ...................................................Virtual
TBD, 10:00 a.m. to 12:00 p.m. ..................................................................Virtual
All DT meeting announcements are for Mountain Time.
10.
Adjourn
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WECC-0148 VAR-501-WECC-4 PSS Drafting Team
Meeting
Virtual
10:00 a.m.—12:00 p.m. Mountain Time, Tuesday, June 28, 2022
Learn More
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Black, Shannon
From:
Sent:
Subject:
Black, Shannon
Monday, July 11, 2022 4:05 PM
WECC-0148 VAR-501-WECC-4 – No Substantive Changes Recommended
WECC-0148 VAR-501-WECC-4 – No Substantive Changes Recommended
Recommendation
The WECC-0148 VAR-501-WECC-4 (VAR), Power System Stabilizer, Drafting Team (DT) is
recommending that no changes be made to the Standard. If the WECC Standards Committee (WSC)
accepts that recommendation, an information-only filing at NERC is recommended.
Overview
On June 21, 2022, the DT began a five-year review of the Standard as required by the WECC
Reliability Standards Development Procedures (Procedures). On July 1, 2022, after reviewing the
entire document during multiple public meetings, the DT unanimously agreed that no Substantive
Changes should be made to the Standard.
Non-Substantive Changes
The DT is recommending the following Non-Substantive Changes:
Updates to the document template, numbering, and boilerplate sections as provided by
NERC
Removal of stale-dated verbiage included in the Effective Date
Removal of the redundant phrase, “[F]or auditing purposes….” From Measure M4
Updates to syntax
Correction of “[s]tandard” to “[S]tandard”
Correction of “dampen” to “damp” in the Rationale and Guidance section
For more information, a redlined version showing the Non-Substantive Changes will be posted to
the WECC-0148 Home Page, on the Posting 1 For Comment accordion. If you have comments or
concerns regarding the recommendation, please contact W. Shannon Black.
1
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
W. Shannon Black, JD
WECC Consultant, Standards Processes
(503) 307-5782
sblack@wecc.org
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Response to Comments
Posting 1—45-Day at NERC
August 16 through September 29, 2023
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Information Only Filing
Posting 1—45-Day NERC
The WECC-0148 VAR-501-WECC-4, Power System Stabilizer Drafting Team (DT) thanks everyone who
submitted comments on the proposed project. WECC-0148 is an information-only filing proposing no
Substantive changes. 1
Posting
This project was posted for comment by NERC from August 16, 2023, through September 29, 2023.
NERC distributed notice for the posting on August 16, 2023.
NERC asked stakeholders to provide feedback on the proposed project through a standardized
electronic template.
NERC reported there “were 9 sets of responses, including comments from approximately 14 different
people from approximately 9 companies representing 4 of the Industry Segments.”
After review of the NERC-provided document, WECC found responses from seven organizations
(some with member organization subcomponents), and 13 persons identified in the following Table of
Respondents.
Location of Comments
All comments provided to WECC by NERC can be reviewed in their original format on the WECC-0148
project page under the “Submit and Review Comments” accordion.
Changes in Response to Comment
After consideration of all comments received, no further changes were made to this project.
The terms Substantive and Non-Substantive are defined terms found in the WECC Relibaility Standards
Development Procedures.
https://www.wecc.org/Reliability/WECC%20Reliability%20Standards%20Development%20Procedures%20%20FERC%20Approved%2009-13-2021.pdf
1
155 No rt h 400 We st | Suit e 200 | Sa lt Lake Cit y , U ta h 84103
www.we c c .o rg
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Minority View
No minority views were raised.
Proposed Effective Date
The proposed Standard can be implemented immediately upon receipt of final regulatory approval.
Information Only—No Substantive Changes
This project represents an “Information Only” filing with no Substantive changes.
Per the WECC Relibaility Standards Development Procedures (Procedures), if no Substantive changes
are requested to a Regional Standard, no further due process is required. Specifically, WECC Board of
Directors (Board) approval is not required.
On July 11, 2022, a list2 of proposed Non-Substantive changes was distributed to the Standards Email
List (SEL) inviting comments or concerns to be forwarded to WECC Standards staff. A redline and a
clean version of the project was posted on the WECC-0148, Posting 1 for Comment accordion. No
comments were received.
On July 16, 2022, WECC posted a letter3 to the WSC informing the WSC of its scope and authority to
address an information only filing. The letter was published to the WECC-0148 home page on the
Posting 1 for Comment accordion.
On December 6, 2022, during a duly noticed WSC meeting, the WSC reviewed the letter from July 16,
2022, and was briefed on the WSC’s Procedural authority to approve the project with no further due
process, so long as all changes were deemed Non-Substantive.
The WSC concurred4 that all proposed changes were Non-Substantive. Because the proposed changes
are all Non-Substantive, the WSC also concurred that neither a posting for comment, ballot, Board
approval, nor an Implementation Plan were required per the Procedures.
Table of Respondents
Organization
1
ACES Power Marketing (ACES)
Bob Soloman, Jodirah Green, Kris Carper
2
Arizona Public Service Company (APS)
Daniel Atanasovski
3
Avista Corporation
Glen Farmer, Mike Magruder, Robert Follini
https://www.wecc.org/Administrative/WECC-0148%20Notice%20of%20No%20Substantive%20Change.pdf
https://www.wecc.org/Reliability/WECC-0148%20VAR-501-WECC-3.1%20%20Letter%20to%20WSC%20Requesting%20Information%20Only%20Filing%20-%20FINAL.docx
4 https://www.wecc.org/Administrative/2022-0316%20WSC%20Proposed%20Meeting%20Minutes%20for%20approval%202022-12-06-2022%20%20FINAL%20FROM%20TECH.docx
2
3
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Organization
4
BC Hydro and Power Authority (BC)
Adrian Andreoiu, Helen Hamilton Harding,
Hootan Jarollahi
5
Bonneville Power Administration (BPA)
Andrea Jessup
6
Salt River Project (SRP)
Israel Perez
7
United States Bureau of Reclamation
Richard Jackson
(USB)
Contacts and Appeals
If you feel your comment has been omitted or overlooked, please contact W. Shannon Black, WECC
Consultant, at (503) 307-5782. In addition, there is a WECC Reliability Standards appeals process.
3
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Index to NERC-provided Questions, Comments, and Responses
Question
1) Do you agree the proposed Regional Reliability Standard was developed in a fair and open
process, using the associated Regional Reliability Standards Development Procedure?
2) Does the proposed Regional Reliability Standard pose an adverse impact to reliability or
commerce in a neighboring region or interconnection?
3) Does the proposed Regional Reliability Standard pose a serious and substantial threat to public
health, safety, welfare, or national security?
4) Does the proposed Regional Reliability Standard pose a serious and substantial burden on
competitive markets within the interconnection that is not necessary for reliability?
5) Does the proposed Regional Reliability Standard meet at least one of the following criteria
a. The proposed Regional Reliability Standard has more specific criteria for the same
requirements covered in a continent-wide standard.
b. The proposed Regional Reliability Standard has requirements that are not included in
the corresponding continent-wide standard.
c. The proposed regional difference is necessitated by a physical difference in the Bulk
Power System.
4
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 1—Do you agree the proposed Regional Reliability Standard was developed in a fair and
open process, using the associated Regional Reliability Standards Development Procedure?
Commenter
Comment or Response
ACES
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
Yes
Response
5
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
6
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 2— Does the proposed Regional Reliability Standard pose an adverse impact to
reliability or commerce in a neighboring region or interconnection?
Commenter
Comment or Response
ACES
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
7
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
8
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 3— Does the proposed Regional Reliability Standard pose a serious and substantial
threat to public health, safety, welfare, or national security?
Commenter
Comment or Response
ACES
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
9
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
10
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 4— Does the proposed Regional Reliability Standard pose a serious and substantial
burden on competitive markets within the interconnection that is not necessary for reliability?
Commenter
Comment or Response
ACES
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
No.
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
11
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
12
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 5—Does the proposed Regional Reliability Standard meet at least one of the following
criteria:
d. The proposed Regional Reliability Standard has more specific criteria for the same
requirements covered in a continent-wide standard.
e.
The proposed Regional Reliability Standard has requirements that are not included in the
corresponding continent-wide standard.
f.
The proposed regional difference is necessitated by a physical difference in the Bulk Power
System.
Commenter
Comment or Response
ACES
Yes. Thank you for the opportunity to comment.
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates Avista’s negative response; however, Avista has failed to
explain their response, identify any issues, or suggest any proposed changes. As such, the DT can neither
identify nor remedy Avista’s concern.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates Avista’s negative response; however, Avista has failed to
explain their response, identify any issues, or suggest any proposed changes. As such, the DT can neither
identify nor remedy Avista’s concern.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
13
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates Avista’s negative response; however, Avista has failed to
explain their response, identify any issues, or suggest any proposed changes. As such, the DT can neither
identify nor remedy Avista’s concern.
Commenter
Comment or Response
BC
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
Yes. While there are regional and physical differences, the
changes proposed are mainly grammatical and all are minor.
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
14
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Letter to WSC Requesting
Information-Only Filing
Recommendation
The WECC‐0148 VAR‐501‐WECC‐4 (VAR), Power System Stabilizer, Drafting Team (DT) is
recommending that no changes be made to the Standard. If the WECC Standards Committee (WSC)
accepts that recommendation, an information‐only filing at NERC is recommended.
Overview
On May 2, 2016, a WECC Ballot Pool approved VAR‐501‐WECC‐3, Power System Stabilizer, after eight
postings for comment. On April 28, 2017, FERC approved the Standard via letter order followed by
Version 3.1 errata on September 26, 2017. Between 2016 and 2022, no known concerns were raised
regarding the text the of the Standard.
On June 21, 2022, the DT began a five‐year review of the Standard as required by the Procedures. On
July 1, 2022, after reviewing the entire document during multiple public meetings, the DT unanimously
agreed that no Substantive Changes1 should be made to the Standard. A straw poll from non‐DT
members in attendance concurred with the DT’s conclusion.
Non-Substantive Changes
The DT is recommending the following Non‐Substantive Changes:
Updates to the document template, numbering, and boilerplate sections as provided by NERC
Removal of stale‐dated verbiage included in the Effective Date
Removal of the redundant phrase, “[F]or auditing purposes….” From Measure M4
Updates to syntax
Correction of “[s]tandard” to “[S]tandard”
Correction of “dampen” to “damp” in the Rationale and Guidance section
1
Definitions, Procedures.
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Letter to WSC Requesting Information-Only Filing
Standard of Review
Per the WECC Standards Committee (WSC) Charter, the WSC administers the Procedures. Per the
Procedures, each of the above proposed changes is a Non‐Substantive Change2, and does not require a
posting for comment.3 Although the Procedures require a ballot to make Non‐Substantive Changes after
a posting for comment4, the Procedures are silent where a DT recommends only Non‐Substantive
Changes, which require neither a posting nor a ballot.
For guidance, the Procedures provide that if the WSC identifies a Non‐Substantive Change after
comments are received, and/or after a ballot has opened, the “correction shall be filed for approval with
NERC”, as appropriate.5 Further, implementing “updated document styles, templates, or standardized
language…is explicitly within the purview of staff and does not require further approval.”6 Finally, as a
matter of precedence, the WSC has previously accepted a “no change” recommendation regarding a
WECC Criterion that had neither been posted nor balloted.7
In light of the above, the DT requests the WSC exercise its discretion by approving the proposed Non‐
Substantive Changes: 1) without a posting, 2) without a ballot, 3) followed by an information‐only
filing at NERC.
Non‐Substantive Changes, Definitions, Procedures, are those changes: “that do not change the scope,
applicability, or intent of any requirement, including correcting the numbering of a requirement, correcting
references, changes to document styles and templates, correcting the spelling of a word, adding an obviously
missing word, or rephrasing a requirement for improved clarity.”
3 “Non‐Substantive Changes do not require a posting/comment/response cycle.” Treatment of Non‐Substantive
Changes, Procedures, page 12.
4 Treatment of Substantive Changes, Procedures, pages 11‐12.
5 “[T]he WSC agrees that the correction of the error does not change the scope or intent of the associated
[Standard], and agrees that the correction has no material impact on the applicable entities, then the correction
shall be filed for approval with NERC and applicable governmental authorities as appropriate.” Treatment of
Non‐Substantive Changes, Regional Reliability Standards, Procedures, page 12.
6 Procedures, page 12.
7 In December 2016, the WSC approved WECC‐0112, COM‐001‐WECC‐CRT‐2.1, Digital Circuits Synchronization,
a WECC Criterion.
2
2
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WECC Standards Committee
Meeting Minutes
December 6, 2022
Virtual
1.
Welcome, Call to Order
James Avery, WECC Standards Committee (WSC) Chair, called the meeting to order at 1:00
p.m. on December 6, 2022. A quorum was established. A list of attendees is attached as Exhibit
A.
2.
Review WECC Antitrust Policy
Steven Rueckert, WECC Director of Standards, read aloud the WECC Antitrust Policy
statement. The meeting agenda included a link to the posted policy.
3.
Approve Agenda
Mr. Avery introduced the proposed meeting agenda.
On a motion by Dana Cabbell, the WSC approved the agenda.
4.
Review and Approve Previous Meeting Minutes
The WSC approved the June 14, 2022, meeting minutes. The WSC did not hold a meeting in
September 2022. A report on the Action Without a Meeting concluding on September 29, 2022,
is included below.
On a motion by Mr. Avery, the WSC approved the minutes.
5.
Review of Previous Action Items
W. Shannon Black reviewed action items carried over from previous meetings of the WSC.
Staff was asked to seek WECC Legal counsel on whether the Western Interconnection
Regional Advisory Body (WIRAB) qualifies for service in Standards Voting Segment
(SVS) 9. Consultation with Chris Albrecht, WECC Legal, concluded that WIRAB does
not meet the criteria for service in SVS 9; however, the WSC recognized the value
provided by WIRAB when networking for that segment. This action is complete.
6.
WECC-0149 Table Revision Project—Request for Ballot
On October 18, 2022, the WECC-0149 Table Revision Process Drafting Team (WECC-0149 DT)
agreed by majority vote to forward the project to the WSC with a request for ballot.
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
The project is a continuation of WECC-0141 FAC-501-WECC-3, Transmission Maintenance. The
project is designed to streamline implementation of WECC-0141 by shifting implementation
away from NERC and back to WECC.
On a motion by Mr. Avery, the WSC approved WECC-0149 Table Revision Process for ballot.
7.
WECC-0150—PRC-001-WECC-CRT-3 Governor Droop—SAR Request—
Convene a Drafting Team
On October 18, 2022, Standard Authorization Request (SAR) WECC-0150 PRC-001-WECC-CRT3, Governor Droop, Five-year Review was received and deemed complete.
The SAR can be reviewed on the WECC-0150 on the SAR Form accordion.
The SAR is a request for five-year review per the Procedures. No issues have been identified.
After review, the drafting team is authorized to recommend “no change” if changes are deemed
unnecessary. This document was last reviewed as WECC-0125.
On a motion by Mr. Avery, the WSC approved Standard Authorization Request PRC-001WECC-CRT-3, Governor Droop, Five-year Review.
The WSC instructed staff to solicit a drafting team.
8.
WECC-0148 VAR-501-WECC-4—Power System Stabilizer/No Change—
Information Only Filing
“No Substantive Change"—Informational Filing Only
On June 21, 2022, the WECC-0148 drafting team (WECC-0148 DT) began a five-year review of
VAR-501-WECC-4, Power System Stabilizer, as required by the Procedures.
On July 1, 2022, after reviewing the entire document during multiple public meetings, the DT
unanimously agreed that no Substantive Changes should be made to the Standard.
On July 11, 2022, a list of proposed non-substantive changes was distributed to the Standards
Email List (SEL) inviting comments or concerns to be forwarded to WECC Standards staff. A
redline and a clean version of the project was posted on the WECC-0148, Posted for Comment
accordion. No comments were received.
Non-substantive changes do not require a posting for comment.1
“Non-Substantive Changes do not require a posting/comment/response cycle. Non-Substantive errors
discovered prior to the opening of a WECC ballot on either an RRS or a CRT may be corrected by WECC staff.”
Treatment of Non-Substantive Changes, Procedures, page 12.
1
2
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
The WSC was briefed on its procedural authority to approve the project with no further due
process, so long as all changes were deemed non-substantive. (See Attachment A, Request for
Information Filing.)
On a motion by Ms. Cabbell, the WSC accepted WECC-0148 VAR-501-WECC-4 (VAR), Power
System Stabilizer as presented with only non-substantive changes.
The WSC instructed staff to prepare an information-only filing for NERC. Per the Procedures,
no further due process is required for this project.
9.
WECC-0151 INT-007-WECC-CRT-4—Processing of Emergency Requests
for Interchange (RFI)/SAR Approval Recommending No Change
“No Substantive Change”—No Further Action Required
The INT suite of WECC Criteria: 1) was originally drafted by and for the use of the subject
matter experts (SME) of the Interchange Scheduling and Accounting Subcommittee (ISAS).
WECC-0151 is due for a five-year review per the Procedures.
On July 15, 2022, Standards staff requested that WECC Staff Liaison, Layne Brown, ask the ISAS
to review WECC-0151 to determine whether the document required substantive changes.
On August 8, 2022, Danielle Smith (Sacramento Municipal Utility District and chair of the ISAS)
reported to Standards staff that members of the ISAS had reviewed the document and were
recommending that no substantive changes be made.2
The following non-substantive change was requested:
Change the footnote from “See Guidance section” to “See Guidance, under Rationale
section.”
On November 1, 2022, a recommendation of “no substantive change” was dispatched to the SEL
inviting comments or concerns to be forwarded to WECC Standards staff. No comments were
received.
On a motion by Mr. Avery, the WSC accepted WECC-0151 INT-007-WECC-CRT-4—
Processing of Emergency Requests for Interchange (RFI) as presented with only nonsubstantive changes.
The leadership of ISAS reviewed WECC-0151 and WECC-0152. Review included the current and out-going
chair, plus the incoming vice-Chair. After individual review, the cohort held a conference reaching consensus on
the proposed non-substantive changes.
2
3
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
This action completes the five-year review required per the Procedures. An updated version of
the WECC Criterion will be published.
10.
WECC-0152 INT-016-WECC-CRT-4—Data Submittal/SAR Approval
Recommending No Change
“No Substantive Change”—No Further Action Required
The INT suite of WECC Criteria: 1) was originally drafted by and for the use of the SMEs of the
ISAS. WECC-0152 is due for a five-year review per the Procedures.
On July 15, 2022, Standards requested that WECC Staff Liaison, Layne Brown, ask the ISAS to
review WECC-0151 to determine whether the document required substantive changes.
On August 8, 2022, Danielle Smith (Sacramento Municipal Utility District and chair of the ISAS)
reported to Standards staff that members of the ISAS had reviewed the document and were
recommending that no substantive changes be made.3
The following non-substantive changes were requested:
In the Rationale section, in the first paragraph of “The Generic use of “Interchange
Software,” replace, “[t]he interchange software currently falls under the purview of Peak
Reliability” with “[t]he interchange software currently falls under the purview of the
ATFWG and under contract with Reliability Coordinator West (RC West).”
On November 1, 2022, a recommendation of “no substantive change” was dispatched to the SEL
inviting comments or concerns to be forwarded to WECC Standards staff. No comments were
received.
On a motion by Mr. Rueckert, the WSC accepted WECC-0152 INT-016-WECC-CRT-4—Data
Submittal as presented with only non-substantive changes.
This action completes the five-year review required per the Procedures. An updated version of
the WECC Criterion will be published.
11.
WECC Glossary of Terms and Naming Conventions—Annual Review
Annual Review—WECC Glossary
The leadership of ISAS reviewed WECC-0150 and WECC-0151. Review included the current and out-going
chair, plus the incoming vice chair. After individual review, the cohort held a conference reaching consensus on
the proposed non-substantive changes.
3
4
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
Per the WSC Charter, the WSC is required to annually review the WECC Glossary of Terms and
Naming Conventions (WECC Glossary). The WECC Glossary only contains terms developed
per the Procedures and used in active WECC Criteria.
Because WECC uses NERC’s numbering and naming nomenclature, much of the WECC
Glossary content duplicates that posted on the NERC website. To streamline the document,
redundancies to the NERC website were deleted from the WECC Glossary and replaced with
references to the NERC source documents.
On a motion by Mr. Rueckert, the WSC approved the annual review of the WECC Glossary
of Terms and Naming Conventions, accepting proposed elimination of redundant language
and changing the document name to WECC Glossary of Terms Used in WECC Criteria.
12.
Annual Election of WSC Vice Chair
On December 7, 2021, Gary Nolan was elected as the WSC Vice Chair. On December 6, 2022,
Mr. Nolan was nominated and affirmed to continue in that role. The WSC thanked Mr. Nolan
for his continued dedication to the Standards development process.
13.
WSC Charter and SVS 9 Application
The WSC reviews its charter annually in December.
On March 16, 2022, the WSC concluded that municipal utilities could be included in SVS 9 –
Government. To ensure this finding is applied in future SVS solicitations, staff suggested
adding the following footnote to the WSC Charter, Committee Composition and Governance,
1b. Membership Eligibility:
“On March 16, 2022, the WSC approved municipal utilities for inclusion in SVS 9.”
Although the footnote was approved for addition, later in the March 16, 2022, meeting, the WSC
rescinded that approval opting instead for further discussion informed by a report by WECC
legal counsel.
After further discussion, the WSC concluded that SVS 9 was tailored to include entities not
otherwise subject to the requirements of a Standard/WECC Criterion. This approach provides a
modicum of checks and balances not otherwise afforded by inclusion of municipalities.
Updates were made to the WSC Charter conforming meeting notice and posting requirements
to those currently administered by WECC support staff.
On a motion by Mr. Avery, the WSC approved changes to the WSC Charter as presented.
The revised WSC Charter will be presented to the WECC Board of Directors during the 2023
Annual Meeting.
5
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
14.
Reports
Standard Voting Segments—Full Cadre
Mr. Black reported that, on June 30, 2022, and July 19, 2022, WECC dispatched a request for
volunteers to serve in Standard Voting Segments (SVS) 2, 3, 5, 6, and 10 with terms of service
terminating coincident with the close of the WECC Annual Meeting in September 2022.
A single nominee for each SVS was received from each incumbent. Per the WSC Charter, a
ballot was waived, and each nominee was deemed elected. The roster was forwarded to the
WECC Board of Directors for informational purposes.
WECC-0149 DT Change
On July 12, 2022, W. Shannon Black was informed that Christopher Fecke-Stoudt had accepted
employment at Salt River Project and would no longer be serving on the WECC-0149 project.
Six members remain on the team.
WECC-0142 Retire BAL-002-WECC-X Contingency Reserve
The WECC-0142 project has not met for 18 months. Their current task is to create technical
justification for the retirement of BAL-002-WECC-X, Contingency Reserve. The WECC-0142 DT
requested to remain active until it creates an actionable work product.
Mr. Avery asked staff to request the WECC-0142 Drafting Team Chair provide a project update
to the WSC at the March 3, 2023 meeting.
15.
Action Without a Meeting
On September 15, 2022, the WECC-0146, TPL-001-WECC-CRT-3, Transmission System Planning
Performance Drafting Team (DT) forwarded the project to the WSC with a request for ballot.
Because the next duly noticed WSC meeting was not scheduled until December 6, 2022, Mr.
Avery approved an Action Without a Meeting (AWM) per the WSC Charter, for the sole
purpose of approving the project for ballot.
On September 29, 2022, the AWM concluded with unanimous support approving the project for
ballot. Balloting on the project is currently scheduled to conclude on December 16, 2022.
16.
Public Comment
Mr. Avery invited public comment.
Alice Ireland, Proven Compliance Solutions, suggested that a due process procedure should be
discussed to address stalled projects. Ms. Ireland suggested that a self-executing approach to
project termination may not be the best approach. The concept was tabled for further
development at the March 2023 meeting.
6
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
17.
Review of New Action Items
Mr. Black reviewed action items carried over from this and previous meetings of the WSC.
WECC-0142
o
Mr. Avery asked staff to request the WECC-0142 Drafting Team Chair provide a
project update to the WSC at the March 3, 2023, meeting. On December 13, 2022,
the request was sent to the WECC-0142 email exploder.
WECC-0148 VAR-501-WECC-4, Power System Stabilizer
o
WECC-0149 Table Revision Project
o
Publish an updated version, no further due process required.
WECC-0152 INT-016-WECC-CRT-4, Data Submittal
o
Solicit a drafting team.
WECC-0151 INT-007-WECC-CRT-4 , Processing of Emergency RFI
o
Ballot the project.
WECC-0150 PRC-001-WECC-CRT-3, Governor Droop
o
Forward an information-only filing to NERC.
Publish an updated version, no further due process required.
WECC Glossary
o
Update and publish the Glossary to include a note explaining that WECC uses
the same naming and numbering nomenclature as that used by NERC.
WSC Charter
o
18.
Update for presentation to the Board in September 2023.
Upcoming Meetings
March 3, 2023, TBD ................................................................................. Salt Lake City, UT
June 13, 20223, TBD ................................................................................. Salt Lake City, UT
December 5, 2023, TBD ........................................................................... Salt Lake City, UT
19.
Adjourn
Mr. Avery adjourned the meeting without objection at 9:40 a.m.
7
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
Exhibit A: Attendance List4
Members in Attendance
Matthew Harward, Southwest Power Pool ................................................................................ SVS 2 RTO/ISO
Dana Cabbell, Southern California Edison .......................................................................................... SVS 3 LSE
Gary Nolan, Arizona Public Service (Proxy Jessica Lopez) .................................................SVS 5 Generators 5
Tim Kelley, Sacramento Municipal Utility District ...............................SVS 6 Broker/Aggregator/Marketers
Crystal Musselman, Proven Compliance Solutions (Proxy Alice Ireland) ... SVS 8 Small Electricity Users6
Steven Rueckert, WECC ................................................................................................ SVS 10 Regional Entities
James Avery, Chair .......................................................................................................... Non-Affiliated Director
Members not in Attendance
Ron Sporseen, Bonneville Power Administration .............................................................SVS 1 Transmission
Marty Hostler, Northern California Power Agency..........................................................................SVS 4 TDU
Caitlin Liotiris, Utah Association of Energy Users .................................... SVS 7 Large Electricity End Users
Chris McLean, California Energy Commission ...................................................................SVS 9 Gov. Entities
Terms of Service for SVSs:
Terms of Service for SVSs 1, 4, 7, 8, and 9 conclude at the close of the 2023 WECC Annual Meeting.
Terms of Service for SVSs 2, 3, 5, 6, and 10 conclude at the close of the 2022 WECC Annual Meeting.
5 On December 5, 2022, Mr. Nolan assigned Ms. Jessica Lopez as proxy for the December 6, 2022, meeting.
6 On November 28, 2022, Ms. Musselman assigned Ms. Alice Ireland as proxy for the December 6, 2022, meeting.
4
8
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
Attachment A
Request for Information-Only Filing
Recommendation
The WECC-0148 VAR-501-WECC-4 (VAR), Power System Stabilizer, Drafting Team (WECC-0148 DT)
is recommending that no substantive changes be made to the Standard. If the WECC Standards
Committee (WSC) accepts that recommendation, an information-only filing at NERC is recommended. 7
Overview
On May 2, 2016, a WECC Ballot Pool approved VAR-501-WECC-3, Power System Stabilizer, after eight
postings for comment. On April 28, 2017, FERC approved the Standard via letter order followed by
Version 3.1 errata on September 26, 2017. Between 2016 and 2022, no known concerns were raised
regarding the text the of the Standard.
On June 21, 2022, the WECC-0148 DT began a five-year review of the Standard as required by the
Procedures. On July 1, 2022, after reviewing the entire document during multiple public meetings, the
DT unanimously agreed that no Substantive Changes8 should be made to the Standard. This position
was reinforced when the project posted for a 30-day comment period and received zero comments for
consideration.
Non-Substantive Changes
The WECC-0148 DT is recommending the following Non-Substantive changes:
Updates to the template and syntax;
Removal of stale-dated language from the Effective Date;
Deletion of “For auditing purposes of…” from M4;
In the Guidance section:
o
“dampen” was replaced with “damp,”
o
Syntax was addressed deleting “still,” “of those,” “of the,”
o
“[t]o ensure” was replaced with “ensuring,”
o
“[w]ash out” was replaced with “washout.”
If “[t]he WSC agrees that the correction of the error does not change the scope or intent of the associated
[project] and agrees that the correction has no material impact on the applicable entities, then the correction shall
be filed for approval with NERC and applicable governmental authorities as appropriate.” Treatment of NonSubstantive Changes, Regional Reliability Standards, Procedures, page 12.
8 Definitions, Procedures.
7
9
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
WSC Meeting Minutes December 6, 2022
Standard of Review
Per the WSC Charter, the WSC administers the Procedures. Per the Procedures, each of the proposed
changes is a Non-Substantive change.9 Non-Substantive changes do not require a posting for
comment.10
Additionally, implementing “updated document styles, templates, or standardized language…is
explicitly within the purview of staff and does not require further approval.” 11 Finally, as a matter of
precedence, the WSC has previously accepted a “no change” recommendation regarding a WECC
Criterion that had neither been posted nor balloted. 12
In light of the above, the WEC-0148 DT requests the WSC exercise its discretion by approving the
proposed Non-Substantive Changes: 1) without a posting, 2) without a ballot, 3) followed by an
information-only filing at NERC.
Non-Substantive Changes, Definitions, Procedures, are those changes: “that do not change the scope,
applicability, or intent of any requirement, including correcting the numbering of a requirement, correcting
references, changes to document styles and templates, correcting the spelling of a word, adding an obviously
missing word, or rephrasing a requirement for improved clarity.”
10 “Non-Substantive Changes do not require a posting/comment/response cycle. Non-Substantive errors
discovered prior to the opening of a WECC ballot on either an RRS or a CRT may be corrected by WECC staff.”
Treatment of Non-Substantive Changes, Procedures, page 12.
11 Procedures, page 12.
12 In December 2016, the WSC approved WECC-0112, COM-001-WECC-CRT-2.1, Digital Circuits Synchronization,
a WECC Criterion.
9
10
Document Accession #: 20231215-5332
Type
Filed Date: 12/15/2023
Title
(1) WECC-0148 VAR-501-WECC-3.1 PSS Info Filing Attachment B -Clean as Approved by NERC
(2) WECC-0148 VAR-501-WECC-4 PSS Info Filing - Attachment A SAR
Modified
2023-07-13
2023-07-13
(3) WECC-0148 VAR-501-WECC-4 PSS Info Filing Attachment E -Project Roadmap
2023-07-13
(4) WECC-0148 VAR-501-WECC-4 PSS Info Filing Attachment D -Redline
2023-07-13
(5) WECC-0148 VAR-501-WECC-4 PSS Info Filing - Attachment C WSC Approved
2023-07-13
(6) WECC-0148 VAR-501-WECC-4 PSS Info Filing Attachment L -Drafting Team Roster
2023-07-13
(7) WECC-0148 VAR-501-WECC-4 PSS Info Filing Attachment T -Additional Supporting Documentation
2023-07-13
(8) WECC-0148 VAR-501-WECC-4 PSS Info Filing - Attachment Q WSC Roster 12-06-2022
2023-07-13
(9) WECC-0148 VAR-501-WECC-4 PSS Info Filing - Attachment J RRS Submittal Request
2023-07-20
(10) WECC-0148 VAR-501-WECC-4 PSS Info Filing - Cover
Letter and Checklist
2023-07-24
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR-501-WECC-3.1 – Power System Stabilizer WECC-0148 Attachment B Clean As Approved by NERC
A. Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR-501-WECC-3.1
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1
Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, that meet the definition of Commercial Operation.
6. Effective Date: The first day of the first quarter following regulatory approval, except
for Requirement R3.
For units placed in first-time service after regulatory approval, Requirement R3 is
effective the first day of the first quarter following final regulatory approval.
For units placed in service prior to final regulatory approval, Requirement R3 is effective
the first day of the first quarter that is five years after regulatory approval.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
• The effective date of this standard;
• The PSS’s Commercial Operation date; or
• Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
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VAR-501-WECC-3.1 – Power System Stabilizer
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
•
Component failure
•
Testing of a Bulk Electric System Element affecting or affected by the PSS
•
Maintenance
•
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
•
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
•
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter-area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
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VAR-501-WECC-3.1 – Power System Stabilizer
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start-up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
•
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
•
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start-up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
For auditing purposes of Requirement R4, bullet one only applies to equipment on its
initial (first energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
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VAR-501-WECC-3.1 – Power System Stabilizer
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority
NERC or the Regional Entity, or any entity as otherwise designated by an
Applicable Governmental Authority, in their respective roles of monitoring and/or
enforcing compliance with mandatory and enforceable Reliability Standards in
their respective jurisdictions.
1.2 Compliance Monitoring and Assessment Processes
•
Compliance Audits
•
Self-Certifications
•
Spot Checking
•
Compliance Investigations
•
Self-Reporting
•
Complaints
1.3 Evidence Retention
The following evidence retention periods identify the period of time an entity is
required to retain specific evidence to demonstrate compliance. For instances
where the evidence retention period specified below is shorter than the time since
the last audit, the Compliance Enforcement Authority may ask an entity to provide
other evidence to show that it was compliant for the full time period since the last
audit.
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.4 Additional Compliance Information
None
D. Regional Differences
None
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VAR-501-WECC-3.1 – Power System Stabilizer
Table of Compliance Elements
R
Time
Horizon
VRF
Violation Severity Levels
Lower VSL
Moderate VSL
High VSL
Severe VSL
R1
Planning
Horizon
Low
NA
NA
NA
The Generator Owner
failed to provide its PSS
operating specifications
to the Transmission
Operator as required in
Requirement R1.
R2
Operations
Assessment
Medium
Each Generator
Operator not having
its PSS in service while
synchronized in
accordance with
Requirement R2, for
more than 30 minutes
but less than 60
minutes.
Each Generator
Operator not having its
PSS in service while
synchronized in
accordance with
Requirement R2, for
more than 60 minutes
but less than 120
minutes.
Each Generator
Operator not having
its PSS in service while
synchronized in
accordance with
Requirement R2, for
more than 120
minutes but less than
180 minutes.
Each Generator
Operator not having
its PSS in service while
synchronized in
accordance with
Requirement R2, for
more than 180
minutes.
R3
Operations
Assessment
Medium
The Generator
Owner’s PSS failed to
meet any of the
required
performances in
Requirement R3, two
times or fewer during
the audit period.
The Generator Owner’s
PSS failed to meet any
of the required
performances in
Requirement R3, three
times during the audit
period.
The Generator
Owner’s PSS failed to
meet any of the
required performances
in Requirement R3,
four times during the
audit period.
The Generator
Owner’s PSS failed to
meet any of the
required performances
in Requirement R3,
five times or more
during the audit
period.
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VAR-501-WECC-3.1 – Power System Stabilizer
R
Time
Horizon
VRF
Violation Severity Levels
R4
Operational
Assessment
Medium
NA
NA
NA
The Generator Owner
failed to install on its
generator a PSS, as
required in
Requirement R4.
R5
Operational
Assessment
Medium
NA
NA
NA
The Generator Owner
failed to repair or
replace a nonoperational PSS as
required in
Requirement R5.
Lower VSL
Moderate VSL
High VSL
Severe VSL
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Document Accession #: 20231215-5332
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Date: 12/15/2023
VAR-501-WECC-3.1 – Power System Stabilizer
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Change Tracking
Permanent Replacement
Standard for VAR-STD-002b-1
Adopted by NERC Board of
Trustees
1
April 21, 2011
FERC Order issued approving
VAR501-WECC-1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR-501-WECC-2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR-501-WECC-3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
3.1
September 26, 2017
FERC letter order issued
approving VAR-501-WECC-3.1
Errata
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VAR-501-WECC-3.1 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to dampen the low-frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while still allowing for some of these
units to be out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either of the triggering events described in
Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non-active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this standard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this standard while also allowing the Generator Owner to create a unit-specific
operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non-active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator-turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this standard’s previous version, the logged hours were totaled quarterly to meet the
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VAR-501-WECC-3.1 – Power System Stabilizer
98% in-service requirement. Instead of documenting the number of hours excluded, this
Requirement simplifies the process by allowing the Generator Operator to communicate to the
Transmission Operator the circumstances that render the PSS unavailable to the Transmission
Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable wash-out time constants, the Requirement specifies 0.2 Hz
as the applicable threshold. The 0.2 Hz threshold more closely aligns with the observed
oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher-frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed-loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
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VAR-501-WECC-3.1 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward to ensure that a unit is tuned,
Requirement R5 looks backward. Specifically, the language in Requirement R5, “becoming
incapable,” indicates the unit was previously capable of meeting the tuning requirements in
Requirement R3, but is no longer capable. Restated, Requirement R5 addresses units that were
previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24-month time frame is sufficient to return a functional, operating PSS to service.
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Document Accession #: 20231215-5332
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VAR-501-WECC-3.1 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR-501-WECC-3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
VAR-501-WECC-3
TBD
TBD
Inactive Date
Page 11 of 11
Document Accession #: 20231215-5332
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Date: 12/15/2023
Attachment A
Standard Authorization Request
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Information Only Filing
Overview
This Standard Authorization Request (SAR) was received March 7, 2022, and deemed complete the
same day. The WECC Standards Committee (WSC) vetted this SAR on March 16, 2022.
This SAR can be reviewed on the WECC‐0148 project page at the Standard Authorization Request
accordion. If you have questions regarding this SAR, please contact W. Shannon Black at (503) 307‐
5782.
Introduction
This is a request for five‐year review of WECC Regional Reliability Standard VAR‐501‐WECC‐3.1
Power System Stabilizer.1
Requester Information
Primary contact
First name:
W. Shannon
Last name:
Black
Email:
sblack@wecc.org
Phone:
(503) 307‐5782
Organization name:
Western Electricity Coordinating Council (WECC)
Alternate
First name:
Donovan
Last name:
Crane
Email:
dcrane@wecc.org
Phone:
(801) 883‐6843
Per the WECC Reliability Standards Procedures, Maintenance of RRSs and CRTs: ‘The WSC shall ensure that
each…RRS is reviewed at least once every five years from the effective date of the most recent version of the
document under review. If the review identifies needed changes, the WSC shall cause a remedial SAR to be filed.
If the review does not identify needed changes, no further action is required.”
1
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Standard Authorization Request
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Five-year Review
Information Only Filing
Type of Request
This is a request for five‐year review of a WECC Regional Reliability Standard.
Create, Modify, Retire or Review a Document
Requested Action (Select one)
This is a request for a five‐year review of a WECC Regional Reliability Standard (RRS).
Document Type (Select one)
WECC Regional Reliability Standard
Issue
This project is assigned WECC Tracking Number WECC‐0148.
This a request for a five‐year review mandated per the WECC Reliability Standards Development
Procedures (Procedures).
Proposed Remedy
This request will review and update the entire document, as needed. No specific concerns have been
identified. The drafting team is authorized to recommend “no change” after reviewing the document.
Applicable Entities
Each function will be reviewed if affected. A dropdown will be provided. Check all applicable blocks.
4. Functional Entities:
4.1. Generator Operator
4.2. Generator Owner
Detailed Description
This request will review and update the entire document, as needed. No specific concerns have been
identified.
Affected Reliability Principles
Reliability Principle 1 — Interconnected bulk power systems shall be planned and operated in
a coordinated manner to perform reliably under normal and abnormal conditions as defined in
the NERC Standards.
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Standard Authorization Request
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Five-year Review
Information Only Filing
Document Information
NA
Reference Uploads
Provide Additional Comments (if needed).
NA
3
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment E
Project Roadmap
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Informational Only Filing
Project Roadmap
Actions
Completed
1.
Standard Authorization Request (SAR) Filed
March 9, 2022
2.
WECC Standards Committee (WSC) approved the SAR
March 16, 2022
3.
Drafting Team (DT) Solicitation
March 30, 2022
4.
DT Meeting
June 21, 2022
5.
DT Meeting
June 28, 2022
6.
7.
8.
Notice to Standard Email List for Proposed Non‐Substantive
Changes – No Substantive Changes Proposed
Posting 1 for Information Only – Comment/Response not
Required
Posting 1 Letter to WSC for Proposed Non‐Substantive Changes
July 11, 2022
9.
WSC Approved Non‐Substantive Changes
December 6, 2022
10.
WECC Board of Directors—Approved
Not Required
11.
Informational Filing pending at NERC
TBD
12.
NERC Board of Trustees Approves
TBD
July 16, 2022
July 16, 2022
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐43.1 – Power System Stabilizer
A. A.
Attachment D
Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR‐501‐WECC‐3.14
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1 Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, that meetmeeting the definition of Commercial Operation.
6. Effective Date: The first day of the first quarter following regulatory approval, except
for Requirement R3.
For units placed in first‐time service after regulatory approval, Requirement R3 is
effective the first day of the first quarter following final regulatory approval.
For units placed in service prior to final regulatory approval, Requirement R3 is effective
the first day of the first quarter that is five years after regulatory approval.
B.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
The effective date of this standard;
The PSS’s Commercial Operation date; or
Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
Component failure
Testing of a Bulk Electric System Element affecting or affected by the PSS
Maintenance
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter‐area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start‐up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start‐up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
For auditing purposes The first bullet of Requirement R4, bullet one only applies to
equipment on its initial (first energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
C. Compliance
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority
: “Compliance Enforcement Authority” means NERC or the Regional Entity, or any entity
as otherwise designated by an Applicable Governmental Authority, in their
respective roles of monitoring and/or enforcing compliance with mandatory and
enforceable Reliability Standards in their respective jurisdictions.
1.2 Compliance Monitoring and Assessment Processes
Compliance Audits
Self‐Certifications
Spot Checking
Compliance Investigations
Self‐Reporting
Complaints
1.3 . Evidence Retention
: The following evidence retention periodsperiod(s) identify the period of time an entity
is required to retain specific evidence to demonstrate compliance. For instances
where the evidence retention period specified below is shorter than the time since
the last audit, the Compliance Enforcement Authority may ask an entity to provide
other evidence to show that it was compliant for the full ‐time period since the last
audit.
The applicable entity shall keep data or evidence to show compliance as identified
below unless directed by its Compliance Enforcement Authority to retain specific
evidence for a longer period of time as part of an investigation.
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.4 Additional Compliance Information
None
D. Regional Differences
None
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Attachment DB
Table of Compliance Elements
1.3 Compliance Monitoring and Enforcement Program: As defined in the NERC Rules of
Procedure, “Compliance Monitoring and Enforcement Program” refers to the
identification of the processes that will be used to evaluate data or information for
the purpose of assessing performance or outcomes with the associated Reliability
Standard.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
R
Violation Severity Levels
Lower VSL
R1 NA
Moderate VSL
High VSL
Severe VSL
NA
NA
The Generator Owner failed to
provide its PSS operating
specifications to the
Transmission Operator as
required in Requirement R1.
R2 Each Generator Operator not
having its PSS in service while
synchronized in accordance with
Requirement R2, for more than 30
minutes but less than 60 minutes.
Each Generator Operator
not having its PSS in service
while synchronized in
accordance with
Requirement R2, for more
than 60 minutes but less
than 120 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 120 minutes but
less than 180 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 180 minutes.
R3 The Generator Owner’s PSS failed
to meet any of the required
performances in Requirement R3,
two times or fewer during the
audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, three times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, four times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, five times or
more during the audit period.
R4 NA
NA
NA
The Generator Owner failed to
install on its generator a PSS,
as required in Requirement R4.
R5 NA
NA
NA
The Generator Owner failed to
repair or replace a non‐
operational PSS as required in
Requirement R5.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
D. Regional Variances
None.
E. Associated Documents
None.
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Permanent Replacement
Standard for VAR‐STD‐002b‐1
Adopted by NERC Board of
Trustees
Change Tracking
1
April 21, 2011
FERC Order issued approving
VAR‐
501‐WECC‐1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR‐501‐WECC‐2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR‐501‐WECC‐3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
Errata
3.1
TBDSeptember 26,
2017
TBDFERC letter order issued
approving VAR‐501‐WECC‐3.1
4
December 6, 2022
WECC Standards Committee
accepted a “no change “
recommendation followed by
Non‐substantive
changes were
approved by the
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
an information‐only filing to
NERC.
WECC Standards
Committee as
allowed in the WECC
Reliability Standards
Development
Procedures. An
information‐only
filing provided to
NERC reflects the
following: 1) updates
to the template and
syntax, 2) removal of
stale‐dated language
from the Effective
Date, 3) deletion of
“For auditing
purposes of…” from
M4, 4) in the
Guidance section,
“dampen” was
replaced with
“damp”, and syntax
was addressed
deleting “still”, “of
those”, “of the”, and
“to ensure” was
replaced with
“ensuring”, and
“wash out” was
replaced with
“washout.”
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to dampendamp the low‐frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while still allowing for some of these
units to be out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either of the triggering eventsevent
described in Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non‐active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this
standardStandard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this standardStandard while also allowing the Generator Owner to create a unit‐
specific operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non‐active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator‐turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this standard’sStandard’s previous version, the logged hours were totaled quarterly
to meet the 98% in‐service requirement. Instead of documenting the number of hours
excluded, this Requirement simplifies the process by allowing the Generator Operator to
communicate to the Transmission Operator the circumstances that render the PSS unavailable
to the Transmission Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function, and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable wash‐outwashout time constants, the Requirement
specifies 0.2 Hz as the applicable threshold. The 0.2 Hz threshold more closely aligns with the
observed oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher‐frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed‐loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward to ensureensuring that a unit is
tuned, Requirement R5 looks backward. Specifically, the language in Requirement R5,
“becoming incapable,” indicates the unit was previously capable of meeting the tuning
requirements in Requirement R3, but is no longer capable. Restated, Requirement R5 addresses
units that were previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24‐month time frame is sufficient to return a functional, operating PSS to service.
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR‐501‐WECC‐3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
Inactive Date
VAR‐501‐WECC‐3
TBD
TBD
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VAR‐501‐WECC‐4 – Power System Stabilizer
Attachment C
A. Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR‐501‐WECC‐4
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1 Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, meeting the definition of Commercial Operation.
6. Effective Date: The first day of the first quarter following regulatory approval.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
The effective date of this standard;
The PSS’s Commercial Operation date; or
Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
Component failure
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VAR‐501‐WECC‐4 – Power System Stabilizer
Testing of a Bulk Electric System Element affecting or affected by the PSS
Maintenance
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter‐area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
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VAR‐501‐WECC‐4 – Power System Stabilizer
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start‐up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start‐up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
The first bullet of Requirement R4 only applies to equipment on its initial (first
energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
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VAR‐501‐WECC‐4 – Power System Stabilizer
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority: “Compliance Enforcement Authority” means
NERC or the Regional Entity, or any entity as otherwise designated by an
Applicable Governmental Authority, in their respective roles of monitoring and/or
enforcing compliance with mandatory and enforceable Reliability Standards in
their respective jurisdictions.
1.2. Evidence Retention: The following evidence retention period(s) identify the period
of time an entity is required to retain specific evidence to demonstrate
compliance. For instances where the evidence retention period specified below is
shorter than the time since the last audit, the Compliance Enforcement Authority
may ask an entity to provide other evidence to show that it was compliant for the
full‐time period since the last audit.
The applicable entity shall keep data or evidence to show compliance as identified
below unless directed by its Compliance Enforcement Authority to retain specific
evidence for a longer period of time as part of an investigation.
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.3 Compliance Monitoring and Enforcement Program: As defined in the NERC Rules of
Procedure, “Compliance Monitoring and Enforcement Program” refers to the
identification of the processes that will be used to evaluate data or information for
the purpose of assessing performance or outcomes with the associated Reliability
Standard.
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VAR‐501‐WECC‐4 – Power System Stabilizer
R
Violation Severity Levels
Lower VSL
R1 NA
Moderate VSL
High VSL
Severe VSL
NA
NA
The Generator Owner failed to
provide its PSS operating
specifications to the
Transmission Operator as
required in Requirement R1.
R2 Each Generator Operator not
having its PSS in service while
synchronized in accordance with
Requirement R2, for more than 30
minutes but less than 60 minutes.
Each Generator Operator
not having its PSS in service
while synchronized in
accordance with
Requirement R2, for more
than 60 minutes but less
than 120 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 120 minutes but
less than 180 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 180 minutes.
R3 The Generator Owner’s PSS failed
to meet any of the required
performances in Requirement R3,
two times or fewer during the
audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, three times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, four times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, five times or
more during the audit period.
R4 NA
NA
NA
The Generator Owner failed to
install on its generator a PSS,
as required in Requirement R4.
R5 NA
NA
NA
The Generator Owner failed to
repair or replace a non‐
operational PSS as required in
Requirement R5.
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VAR‐501‐WECC‐4 – Power System Stabilizer
D. Regional Variances
None.
E. Associated Documents
None.
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Permanent Replacement
Standard for VAR‐STD‐002b‐1
Adopted by NERC Board of
Trustees
Change Tracking
1
April 21, 2011
FERC Order issued approving
VAR‐
501‐WECC‐1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR‐501‐WECC‐2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR‐501‐WECC‐3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
Errata
3.1
September 26, 2017
FERC letter order issued
approving VAR‐501‐WECC‐3.1
December 6, 2022
WECC Standards Committee
accepted a “no change “
recommendation followed by
Non‐substantive
changes were
approved by the
4
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VAR‐501‐WECC‐4 – Power System Stabilizer
an information‐only filing to
NERC.
WECC Standards
Committee as
allowed in the WECC
Reliability Standards
Development
Procedures. An
information‐only
filing provided to
NERC reflects the
following: 1) updates
to the template and
syntax, 2) removal of
stale‐dated language
from the Effective
Date, 3) deletion of
“For auditing
purposes of…” from
M4, 4) in the
Guidance section,
“dampen” was
replaced with
“damp”, and syntax
was addressed
deleting “still”, “of
those”, “of the”, and
“to ensure” was
replaced with
“ensuring”, and
“wash out” was
replaced with
“washout.”
Page 7 of 11
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VAR‐501‐WECC‐4 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to damp the low‐frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while allowing for some units to be
out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either triggering event described in
Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non‐active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this Standard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this Standard while also allowing the Generator Owner to create a unit‐specific
operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non‐active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator‐turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
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VAR‐501‐WECC‐4 – Power System Stabilizer
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this Standard’s previous version, the logged hours were totaled quarterly to meet
the 98% in‐service requirement. Instead of documenting the number of hours excluded, this
Requirement simplifies the process by allowing the Generator Operator to communicate to the
Transmission Operator the circumstances that render the PSS unavailable to the Transmission
Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function, and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable washout time constants, the Requirement specifies 0.2 Hz
as the applicable threshold. The 0.2 Hz threshold more closely aligns with the observed
oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher‐frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed‐loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
Page 9 of 11
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐4 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward ensuring that a unit is tuned,
Requirement R5 looks backward. Specifically, the language in Requirement R5, “becoming
incapable,” indicates the unit was previously capable of meeting the tuning requirements in
Requirement R3, but is no longer capable. Restated, Requirement R5 addresses units that were
previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24‐month time frame is sufficient to return a functional, operating PSS to service.
Page 10 of 11
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐4 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR‐501‐WECC‐3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
Inactive Date
VAR‐501‐WECC‐3
TBD
TBD
Page 11 of 11
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment L
Drafting Team Roster
WECC-0148 VAR-501-WECC-4
Five-year Review
Drafting Team Roster
Below please find a brief biography for each member of the WECC‐0148 VAR‐501‐WECC‐4, Power
System Stabilizer, Five‐year Review Drafting Team.
Name
Qualifications
Greg Anderson,
Mr. Anderson is the subject matter expert for generation and excitation
Southern
systems for the Southern California Edison Company. He has over 33
California Edison
years of experience in the utility industry, with responsibilities for
coordinating WECC testing of generation assets. He has been a WECC
participant since 1997 and a member of the Control Work Group since
2003.
Joel Anthes,
Pacific Gas and
Electric
Mr. Anthes is a Senior Electrical Engineer with Pacific Gas and Electric
Company’s Power Generation organization. Mr. Anthes has more than 16
years of experience in the electrical and power generation industries. Over
the past nine years, he has led the development of multiple technical
programs related to electrical generation and excitation system protection,
control system tuning and modeling, and generator electrical ratings. Mr.
Anthes is a registered professional engineer in the state of California and
plays an active role in the development of industry best practices and
regulatory standards for NERC. Recent experience includes:
• Member of the drafting team for NERC Project 2020‐02
Transmission‐connected Dynamic Reactive Resources.
• Power system stabilizer (PSS) tuning and validation.
• Development of tools for numerical calculation of generator field
current. Performs generator heat runs to prove safe increase of
electrical rating beyond existing nameplate.
• Development of program for dynamic modeling of generators,
voltage regulators, governors, and power system stabilizers.
Development of associated programs for NERC regulatory
compliance.
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment L
• Developed custom tools for determining generator electrical
characteristics, impedances, time constants, phase response, and
capability curves for synchronous generators. Oversees training of
other engineers in the proper implementation of these tools.
• Commissions and tests excitation systems, voltage regulators, and
power system stabilizers.
• Performs Root Cause Analyses using industry standard
methodologies for operational safety incidents and major
equipment failures.
Developed recommendations for corrective actions to effectively
prevent the recurrence of equipment failure and human
performance errors.
Shane Kronebusch, Mr. Kronebusch is the Lead Electrical Engineer and subject matter expert
L&S Electric, Inc.
for generation and excitation systems for L&S Electric, Inc. He has over 31
years of experience in the utility industry, including:
Developing the LS‐AES excitation system.
Designing, installing, and commissioning exciters and governors
across a wide range of units.
Performing of testing and model validation reports for NERC
MOD‐025, ‐026, & ‐027.
Coordinating and preforming WECC testing of generation assets as
an employee of BC Hydro Generation Engineering and
Maintenance Services before joining L&S Electric, Inc. in 2010.
Participating as a member of the WECC Control Work Group since
2006 and drafting team member of WECC‐0099/0107.
Matthew
Mr. McDonald is a Senior Electrical Engineer in the Technical Projects
McDonald, Arizona Engineering department with 15 years of experience in the utility industry.
Public Service
He holds a Bachelor of Science from Pennsylvania State University as well
as a professional engineering license. His expertise and experience include
the following:
13 years’ hands‐on experience installing, troubleshooting,
commissioning, and tuning excitation systems and generator
protection relays.
Five years of experience performing generator, excitation, and PSS
model validation via simulation and live testing.
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment L
Excitation system subject matter expert for Arizona Public Service
for the past four years.
NERC/WECC compliance lead for VAR‐501‐3, PRC‐19‐2, PRC‐002,
PRC‐27‐1 and PRC‐25‐2.
Other responsibilities and roles have included generator excitation
instructor, improvisational field testing, synchro‐phasor and digital
fault recorder commissioning.
Kimberly Turco,
Ms. Turco has worked for Constellation Energy Generation (CEG) for 10
Constellation
years, with the last two years in NERC compliance and supporting ISO
Energy
compliance. CEG is actively involved in NERC’s Standards Under
Development process and would like to take this opportunity for direct
involvement in the review of VAR‐501‐WECC. Kim comes with a wide
background in energy and compliance that would be an asset in the
standards review process.
Kim’s background:
Worked as a subject matter expert in AESO in day‐ahead bidding
and electronic transaction systems (ETS).
Drafted CEG’s Grande Prairie Generation generating station’s
Transmission Must Run Contract.
A barred attorney.
NERC compliance SME and compliance contact for CEG’s WECC
and Alberta generating facilities.
Lead on historical submittal of Automatic Voltage Regulator and
Power System Stabilizer Outage reporting.
Kim has the full support of CEG’s NERC Compliance Group and will be
able to dedicate the time and resources demanded of a member of the
Standards Drafting Team.
3
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment T
Additional Supporting Documentation
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Non-Substantive Change / Information Only Filing
Letter to WSC Requesting
Information-Only Filing
Preamble
On July 16 2022, the following letter was posted on the WECC‐0148 VAR‐501‐WECC‐4, Power System
Stabilizer home page at the Posting 1 accordion. It was also provided to the WECC Standards
Committee (WSC) for its consideration during the December 6, 2022, WSC meeting.
Recommendation
The WECC‐0148 VAR‐501‐WECC‐4 (VAR), Power System Stabilizer, Drafting Team (DT) is
recommending that no changes be made to the Standard. If the WECC Standards Committee (WSC)
accepts that recommendation, an information‐only filing at NERC is recommended.
Overview
On May 2, 2016, a WECC Ballot Pool approved VAR‐501‐WECC‐3, Power System Stabilizer, after eight
postings for comment. On April 28, 2017, FERC approved the Standard via letter order followed by
Version 3.1 errata on September 26, 2017. Between 2016 and 2022, no known concerns were raised
regarding the text the of the Standard.
On June 21, 2022, the DT began a five‐year review of the Standard as required by the Procedures. On
July 1, 2022, after reviewing the entire document during multiple public meetings, the DT unanimously
agreed that no Substantive Changes1 should be made to the Standard. A straw poll from non‐DT
members in attendance concurred with the DT’s conclusion.
Non-Substantive Changes
The DT is recommending the following Non‐Substantive Changes:
Updates to the document template, numbering, and boilerplate sections as provided by NERC
Removal of stale‐dated verbiage included in the Effective Date
1
Definitions, Procedures.
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment T
Letter to WSC Requesting Information-Only Filing
Removal of the redundant phrase, “[F]or auditing purposes….” From Measure M4
Updates to syntax
Correction of “[s]tandard” to “[S]tandard”
Correction of “dampen” to “damp” in the Rationale and Guidance section
Standard of Review
Per the WECC Standards Committee (WSC) Charter, the WSC administers the Procedures. Per the
Procedures, each of the above proposed changes is a Non‐Substantive Change2, and does not require a
posting for comment.3 Although the Procedures require a ballot to make Non‐Substantive Changes after
a posting for comment4, the Procedures are silent where a DT recommends only Non‐Substantive
Changes, which require neither a posting nor a ballot.
For guidance, the Procedures provide that if the WSC identifies a Non‐Substantive Change after
comments are received, and/or after a ballot has opened, the “correction shall be filed for approval with
NERC”, as appropriate.5 Further, implementing “updated document styles, templates, or standardized
language…is explicitly within the purview of staff and does not require further approval.”6 Finally, as a
matter of precedence, the WSC has previously accepted a “no change” recommendation regarding a
WECC Criterion that had neither been posted nor balloted.7
In light of the above, the DT requests the WSC exercise its discretion by approving the proposed Non‐
Substantive Changes: 1) without a posting, 2) without a ballot, 3) followed by an information‐only
filing at NERC.
Non‐Substantive Changes, Definitions, Procedures, are those changes: “that do not change the scope,
applicability, or intent of any requirement, including correcting the numbering of a requirement, correcting
references, changes to document styles and templates, correcting the spelling of a word, adding an obviously
missing word, or rephrasing a requirement for improved clarity.”
3 “Non‐Substantive Changes do not require a posting/comment/response cycle.” Treatment of Non‐Substantive
Changes, Procedures, page 12.
4 Treatment of Substantive Changes, Procedures, pages 11‐12.
5 “[T]he WSC agrees that the correction of the error does not change the scope or intent of the associated
[Standard], and agrees that the correction has no material impact on the applicable entities, then the correction
shall be filed for approval with NERC and applicable governmental authorities as appropriate.” Treatment of
Non‐Substantive Changes, Regional Reliability Standards, Procedures, page 12.
6 Procedures, page 12.
7 In December 2016, the WSC approved WECC‐0112, COM‐001‐WECC‐CRT‐2.1, Digital Circuits Synchronization,
a WECC Criterion.
2
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment T
Letter to WSC Requesting Information-Only Filing
Subsequent Entry
On December 6, 2022, the WSC approved the requested Non‐Substantive Changes and instructed staff
to provide NERC with an information‐only filing.
3
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment Q
WECC Standards Committee Roster
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Non-Substantive Change / Information Only Filing
WECC Standards Committee Roster
The following individuals are those assigned to the WECC Standards Committee as of December 6,
2022.
Ron Sporseen, Bonneville Power Administration ............................................................ SVS 1 Transmission
Matthew Harward, Southwest Power Pool ................................................................................ SVS 2 RTO/ISO
Dana Cabbell, Southern California Edison .......................................................................................... SVS 3 LSE
Marty Hostler, Northern California Power Agency ......................................................................... SVS 4 TDU
Gary Nolan, Arizona Public Service ........................................................................................ SVS 5 Generators
Tim Kelley, Sacramento Municipal Utility District .............................. SVS 6 Broker/Aggregator/Marketers
Caitlin Liotiris, Utah Association of Energy Users .................................... SVS 7 Large Electricity End Users
Crystal Musselman, Proven Compliance Solutions .......................................... SVS 8 Small Electricity Users
Chris McLean, California Energy Commission ................................................................... SVS 9 Gov. Entities
Steven Rueckert, WECC ................................................................................................ SVS 10 Regional Entities
James Avery, Chair .......................................................................................................... Non‐Affiliated Director
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Regional Reliability Standard Submittal Request
Attachment J
Western Electricity Coordinating Council
Region:
Regional Standard Number:
VAR‐501‐WECC‐41
Regional Standard Title:
Power System Stabilizer
Date Submitted:
July 20, 2023
Regional Contact Name:
Steven Rueckert
Regional Contact Title:
Director of Standards
Regional Contact Telephone
(801) 883‐6878
Number:
Request (check all that apply):
Retirement of WECC Regional Reliability Standard
Interpret an Existing Standard
Approval of a new standard
Modification of Existing WECC Regional Standard VAR‐501‐WECC‐4 – Information Only
Withdrawal of an existing standard
Urgent Action
Has this action been approved by your Board of Directors:
No
Yes
(If no, please indicate date standard action is expected along with the current status (e.g., third
comment period with anticipated board approval on mm/dd/year)):
Per the WECC Reliability Standards Development Procedures (Procedures), approval of
Non‐Substantive Changes to a Regional Reliability Standard (RRS) do not require WECC
Board of Director (Board) approval.
1
Numbering is subject to NERC assignment.
1
Regional Reliability Standard Submittal Request
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
The WECC Standards Committee (WSC) is empowered by the Procedures to address Non‐
Substantive changes without Board review.
Excerpt from December 6, 2022, WECC Standards Committee minutes:
Item 8:
WECC‐0148 VAR‐501‐WECC‐4 – Power System Stabilizer / No Change – Information Only Filing
“No Substantive Change”‐ Informational Filing Only
On June 21, 2022, the WECC‐0148 drafting team (WECC‐0148 DT) began a five‐year review of VAR‐
501‐WECC‐3.1, Power System Stabilizer, as required by the Procedures.
On July 1, 2022, after reviewing the entire document during multiple public meetings, the DT
unanimously agreed that no Substantive Changes should be made to the Standard.
On July 11, 2022, a list of proposed Non‐Substantive Changes was distributed to the Standards
Email List (SEL) inviting comments or concerns to be forwarded to WECC Standards staff. A redline
and a clean version of the project was posted on the WECC‐0148, Posted for Comment 1
accordion. No comments were received.
Non‐Substantive changes do not require a posting for comment.2
The WSC was briefed on its Procedural authority to approve the project with no further due
process, so long as all changes were deemed Non‐Substantive. (See Attachment A, Request for
Information Filing.)
On a motion by Ms. Cabbell, the WSC accepted WECC‐0148 VAR‐501‐WECC‐4 (VAR), Power
System Stabilizer as presented with only non‐substantive changes.
The WSC instructed staff to prepare an information‐only filing for NERC. Per the Procedures, no
further due process is required for this project.
[Note: The purpose of the remaining questions is to provide NERC with the information needed
to file the regional standard(s) with FERC. The information provided may to a large degree be
used verbatim. It is extremely important for the entity submitting this form to provide sufficient
detail that clearly delineates the scope and justification of the request.]
Not Used.
2
“Non-Substantive Changes do not require a posting/comment/response cycle. Non-Substantive errors discovered prior to
the opening of a WECC ballot on either an RRS or a CRT may be corrected by WECC staff.” Treatment of Non-Substantive
Changes, Procedures, page 12.
2
Regional Reliability Standard Submittal Request
Document Accession #: 20231215-5332
Concise statement of the
basis and purpose (scope)
of request:
Concise statement of the
justification of the
request:
Filed
Date: 12/15/2023
This request makes Non‐Substantive Changes to VAR‐501‐WECC‐
3.1, Power System Stabilizer.
Non‐Substantive Changes approved by the WECC Standards
Committee (WSC) do not require a Posting/Comment/Response
cycle nor further due process at WECC.
Non‐Substantive Changes were approved by the WSC on December
6, 2022.
This listing of WSC‐approved Non‐Substantive Changes appears in
the VAR‐501‐WECC‐4, Power System Stabilizer Version History
Table:
“An information‐only filing provided to NERC reflects the following:
1) Updates to the template and syntax,
2) Removal of stale‐dated language from the Effective Date,
3) Deletion of “For auditing purposes of…” from M4,
4) In the Guidance section, “dampen” was replaced with “damp”,
and syntax was addressed deleting “still”, “of those”, “of the”, and
“to ensure” was replaced with “ensuring”, and “wash out” was
replaced with “washout.”
See WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer
Informational Filing – Attachment T – Supporting
Documentation
3
Regional Reliability Standard Submittal Request
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Steven Rueckert
WECC Director of Standards
July 20, 2023
Ms. Kimberlin Harris
NERC Reliability Standards Department
North American Electric Reliability Corporation
3353 Peachtree Rd. NE, North Tower – Suite 600
Atlanta, GA 30326
Subject:
VAR‐501‐WECC‐4, Power System Stabilizer
Non‐Substantive Changes/Informational Filing Only
Dear Kimberlin,
Per the WECC Reliability Standards Development Procedures (Procedures), the WECC Standards
Committee (WSC) ensures each Regional Reliability Standard undergoes a substantive review at least
once every five years.1
VAR‐501‐WECC‐3, Power System Stabilizer became due for review in September 2022.
On July 1, 2022, after reviewing the entire document during multiple public meetings, a drafting team
of subject matter experts unanimously agreed that no Substantive Changes should be made to the
Standard.2
On July 11, 2022, a list of proposed Non‐Substantive changes was distributed to the WECC Standards
Email List (SEL) inviting comments or concerns to be forwarded to WECC Standards staff regarding
the proposed Non‐Substantive changes.3 No comments were received.
Non‐Substantive changes do not require a posting for comment. Approval of Non‐Substantive changes
is within the purview of the WSC.4
Maintenance of RRSs and CRTs, Procedures, page 21. FERC approved September 13, 2021.
Substantive Change: A change that alters the scope, applicability, required actions, or intent of the document.
Definitions, Procedures, page 3.
3 Non‐Substantive Change: Revisions that do not change the scope, applicability, or intent of any requirement,
including correcting the numbering of a requirement, correcting references, changes to document styles and
templates, correcting the spelling of a word, adding an obviously missing word, or rephrasing a requirement for
improved clarity. Definitions, Procedures, page 3.
4 Treatment of Non‐Substantive Changes, Procedures, page 12.
1
2
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 VAR-501-WECC-4 – Power System Stabilizer
Non-Substantive Change/Information Only Filing
On December 6, 2022, the WSC approved Non‐Substantive changes to the Standard with instructions
that an information‐only filing be provided to NERC.5
Attached please find:
A redline of the as‐approved Standard showing WSC‐approved Non‐Substantive changes. A
list of the approved changes is included in the version table of the Standard.
A clean version of VAR‐501‐WECC‐4, Power System Stabilizer.
Because the WSC‐approved changes do not affect application of the Standard, an implementation plan
is not needed.
This filing concludes WECC’s required due process per the Procedures. Please update the NERC‐
controlled version of the Standard.
If you have questions, please feel free to contact me.
Sincerely,
Steven Rueckert
WECC Director of Standards
Loc. Cit. See also WSC Minutes for December 6, 2022.
5
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 VAR-501-WECC-4 – Power System Stabilizer
Non-Substantive Change/Information Only Filing
For documentation support, please contact W. Shannon Black at (503) 307‐5782.
WECC‐0148 VAR‐501‐WECC‐4 – Power System Stabilizer / No Change –
QR
BOT Gov’t
Information Only Filing
SAR – Standard Authorization Request Attachment A
Auth.*
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing ‐ Attachment A
SAR
Regional Reliability Standard(s) (Clean Existing) Attachment B
File Name: WECC‐0148 VAR‐501‐WECC‐3.1 Power System Stabilizer Informational Filing ‐ Attachment
B ‐ Clean as Approved by NERC
Regional Reliability Standard(s) (Clean Proposed) Attachment C
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing ‐ Attachment C
– WSC Approved
Regional Reliability Standard(s) (Existing redlined to Proposed)
Attachment D
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing‐ Attachment D
– Redline
Project Roadmap Attachment E
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing‐ Attachment E
Project Roadmap
Implementation Plan Attachment F
File Name: Not Used
Technical Justification Attachment G
File Name: Not Used
VRF & VSL Justification Attachment H
File Name: Not Used
Issue Table and Mapping Document Attachment I – Optional
File Name: Not Used
3
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 VAR-501-WECC-4 – Power System Stabilizer
Non-Substantive Change/Information Only Filing
Regional Reliability Standard Submittal Request Attachment J
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing ‐ Attachment J
Regional Reliability Standard Submittal Request
Order 672 Criteria Attachment K
File Name: Not Used
Drafting Team Roster with Biographies Attachment L
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing ‐ Attachment L ‐
Drafting Team Roster
Ballot Pool Members Attachment M
File Name: Not Used
Final Ballot Results Attachment N
File Name: Not Used
Guidance Document Attachment O – Optional
File Name: Not Used
Minority Issues Attachment P
File Name: Not Used
WECC Standards Committee Roster Attachment Q
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing ‐ Attachment Q
– WSC Roster 12‐06‐2022
Responses to Comments – WECC Attachment R
File Name: Not Used
FERC Issues Table Attachment S – Optional
File Name: Not Used
Additional Supporting Documentation Attachment T
File Name: WECC‐0148 VAR‐501‐WECC‐4 Power System Stabilizer Informational Filing ‐ Attachment T
– Supporting Documentation
Petition Filing (FERC) Attachment U – Optional
4
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 VAR-501-WECC-4 – Power System Stabilizer
Non-Substantive Change/Information Only Filing
File Name: Not Used
*Applicable governmental authorities in the United States, Canada, and Mexico
To be provided by NERC.
5
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
(4) Unofficial Comment Form (Word)
(5) Submit Comments
(6) Comments Received
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Regional Reliability Standards
Announcement
Western Electricity Coordinating Council
VAR-501-WECC-4
Comment Period Open through September 29, 2023
Now Available
Western Electricity Coordinating Council (WECC) requested that NERC post Regional Reliability
Standard VAR-501-WECC-4 (Power System Stabilizer) for industry review and comment in accordance
with the NERC Rules of Procedure.
Background
Proposed Regional Reliability Standard VAR-501-WECC-4 – Power System Stabilizer modifies the currently
effective regional standard VAR-501-WECC-3.1 as follows:
•
Updates to the document template, numbering, and template sections as provided by NERC
•
Removal of stale-dated verbiage included in the Effective Date
•
Removal of the redundant phrase, “[F]or auditing purposes….” From Measure M4
•
Updates to syntax
•
Correction of “[s]tandard” to “[S]tandard”
•
Correction of “dampen” to “damp” in the Rationale and Guidance section
The WECC Board of Directors approved the proposed regional standard on June 14, 2023.
Commenting
Use the Standards Balloting and Commenting System (SBS) to submit comments. Comments must be
submitted by 8 p.m. Eastern, Friday, September 29, 2023. An unofficial Word version of the comment
form is posted on the Regional Reliability Standards Under Development page.
•
Contact NERC IT support directly at https://support.nerc.net/ (Monday – Friday, 8 a.m. - 5 p.m.
Eastern) for problems regarding accessing the SBS due to a forgotten password, incorrect
credential error messages, or system lock-out.
•
Passwords expire every 6 months and must be reset.
•
The SBS is not supported for use on mobile devices.
RELIABILITY | RESILIENCE | SECURITY
Document Accession #: 20231215-5332
•
Filed Date: 12/15/2023
Please be mindful of ballot and comment period closing dates. We ask to allow at least 48 hours
for NERC support staff to assist with inquiries. Therefore, it is recommended that users try logging
into their SBS accounts prior to the last day of a comment/ballot period.
Regional Reliability Standards Development Process
Section 300 of NERC’s Rules of Procedures of the Electric Reliability Organization governs the regional
reliability standards development process. Although the technical aspects of this Regional Reliability
Standard have been vetted through WECC Regional Standards development process, the final approval
process for a Regional Reliability Standard requires NERC publicly to notice and request comment on the
criteria outlined in the unofficial comment form.
Documents and information about this project are available on the Western Electricity Coordinating
Council (WECC) Standards page.
For more information or assistance, contact Reliability Standards Analyst, Kimberlin Harris (via email) or at
(404) 446-9794.
North American Electric Reliability Corporation
3353 Peachtree Rd, NE
Suite 600, North Tower
Atlanta, GA 30326
404-446-2560 | www.nerc.com
Regional Reliability Standards Announcement
VAR-501-WECC-4 | August 16 – September 29, 2023
2
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
VAR-501-WECC-4 – Power System Stabilizer
Attachment C
A. Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR-501-WECC-4
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1
Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, meeting the definition of Commercial Operation.
6. Effective Date:
The first day of the first quarter following regulatory approval.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
• The effective date of this standard;
• The PSS’s Commercial Operation date; or
• Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
•
Component failure
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VAR-501-WECC-4 – Power System Stabilizer
•
Testing of a Bulk Electric System Element affecting or affected by the PSS
•
Maintenance
•
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
•
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
•
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter-area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
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VAR-501-WECC-4 – Power System Stabilizer
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start-up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
•
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
•
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start-up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
The first bullet of Requirement R4 only applies to equipment on its initial (first
energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
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VAR-501-WECC-4 – Power System Stabilizer
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority: “Compliance Enforcement Authority” means
NERC or the Regional Entity, or any entity as otherwise designated by an
Applicable Governmental Authority, in their respective roles of monitoring and/or
enforcing compliance with mandatory and enforceable Reliability Standards in
their respective jurisdictions.
1.2. Evidence Retention: The following evidence retention period(s) identify the period
of time an entity is required to retain specific evidence to demonstrate
compliance. For instances where the evidence retention period specified below is
shorter than the time since the last audit, the Compliance Enforcement Authority
may ask an entity to provide other evidence to show that it was compliant for the
full-time period since the last audit.
The applicable entity shall keep data or evidence to show compliance as identified
below unless directed by its Compliance Enforcement Authority to retain specific
evidence for a longer period of time as part of an investigation.
•
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.3 Compliance Monitoring and Enforcement Program: As defined in the NERC Rules of
Procedure, “Compliance Monitoring and Enforcement Program” refers to the
identification of the processes that will be used to evaluate data or information for
the purpose of assessing performance or outcomes with the associated Reliability
Standard.
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VAR-501-WECC-4 – Power System Stabilizer
R
Violation Severity Levels
Lower VSL
R1
Moderate VSL
High VSL
Severe VSL
NA
NA
NA
The Generator Owner failed to
provide its PSS operating
specifications to the
Transmission Operator as
required in Requirement R1.
Each Generator Operator not
having its PSS in service while
synchronized in accordance with
Requirement R2, for more than 30
minutes but less than 60 minutes.
Each Generator Operator
not having its PSS in service
while synchronized in
accordance with
Requirement R2, for more
than 60 minutes but less
than 120 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 120 minutes but
less than 180 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 180 minutes.
The Generator Owner’s PSS failed
to meet any of the required
performances in Requirement R3,
two times or fewer during the
audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, three times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, four times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, five times or
more during the audit period.
R4
NA
NA
NA
The Generator Owner failed to
install on its generator a PSS,
as required in Requirement R4.
R5
NA
NA
NA
The Generator Owner failed to
repair or replace a nonoperational PSS as required in
Requirement R5.
R2
R3
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VAR-501-WECC-4 – Power System Stabilizer
D. Regional Variances
None.
E. Associated Documents
None.
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Permanent Replacement
Standard for VAR-STD-002b-1
Adopted by NERC Board of
Trustees
1
April 21, 2011
FERC Order issued approving
VAR501-WECC-1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR-501-WECC-2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR-501-WECC-3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
3.1
September 26, 2017
FERC letter order issued
approving VAR-501-WECC-3.1
December 6, 2022
WECC Standards Committee
accepted a “no change “
recommendation followed by
4
Change Tracking
Errata
Non-substantive
changes were
approved by the
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VAR-501-WECC-4 – Power System Stabilizer
an information-only filing to
NERC.
4
WECC Standards
Committee as
allowed in the WECC
Reliability Standards
Development
Procedures. An
information-only
filing provided to
NERC reflects the
following: 1) updates
to the template and
syntax, 2) removal of
stale-dated language
from the Effective
Date, 3) deletion of
“For auditing
purposes of…” from
M4, 4) in the
Guidance section,
“dampen” was
replaced with
“damp”, and syntax
was addressed
deleting “still”, “of
those”, “of the”, and
“to ensure” was
replaced with
“ensuring”, and
“wash out” was
replaced with
“washout.”
TBD
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VAR-501-WECC-4 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to damp the low-frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while allowing for some units to be
out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either triggering event described in
Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non-active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this Standard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this Standard while also allowing the Generator Owner to create a unit-specific
operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non-active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator-turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
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VAR-501-WECC-4 – Power System Stabilizer
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this Standard’s previous version, the logged hours were totaled quarterly to meet
the 98% in-service requirement. Instead of documenting the number of hours excluded, this
Requirement simplifies the process by allowing the Generator Operator to communicate to the
Transmission Operator the circumstances that render the PSS unavailable to the Transmission
Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function, and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable washout time constants, the Requirement specifies 0.2 Hz
as the applicable threshold. The 0.2 Hz threshold more closely aligns with the observed
oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher-frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed-loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
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VAR-501-WECC-4 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward ensuring that a unit is tuned,
Requirement R5 looks backward. Specifically, the language in Requirement R5, “becoming
incapable,” indicates the unit was previously capable of meeting the tuning requirements in
Requirement R3, but is no longer capable. Restated, Requirement R5 addresses units that were
previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24-month time frame is sufficient to return a functional, operating PSS to service.
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VAR-501-WECC-4 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR-501-WECC-3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
VAR-501-WECC-3
TBD
TBD
Inactive Date
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Date: 12/15/2023
VAR‐501‐WECC‐43.1 – Power System Stabilizer
A. A.
Attachment D
Introduction
1. Title:
Power System Stabilizer (PSS)
2. Number: VAR‐501‐WECC‐3.14
3. Purpose: To ensure the Western Interconnection is operated in a coordinated manner
under normal and abnormal conditions by establishing the performance criteria for
WECC power system stabilizers.
4. Applicability:
4.1 Generator Operator
4.2 Generator Owner
5. Facilities: This standard applies to synchronous generators, connected to the Bulk
Electric System, that meetmeeting the definition of Commercial Operation.
6. Effective Date: The first day of the first quarter following regulatory approval, except
for Requirement R3.
For units placed in first‐time service after regulatory approval, Requirement R3 is
effective the first day of the first quarter following final regulatory approval.
For units placed in service prior to final regulatory approval, Requirement R3 is effective
the first day of the first quarter that is five years after regulatory approval.
B.
B. Requirements and Measures
R1. Each Generator Owner shall provide to its Transmission Operator, the Generator
Owner’s written Operating Procedure or other document(s) describing those known
circumstances during which the Generator Owner’s PSS will not be providing an active
signal to the Automatic Voltage Regulator (AVR), within 180 days of any of the
following events: [Violation Risk Factor: Low] [Time Horizon: Planning Horizon]
The effective date of this standard;
The PSS’s Commercial Operation date; or
Any changes to the PSS operating specifications.
M1. Each Generator Owner will have documented evidence that it provided to its
Transmission Operator, within the time allotted as described in the procedures
required under Requirement R1, written Operating Procedures or other document(s)
describing those known circumstances during which the Generator Owner’s PSS will
not be providing an active signal to the AVR.
For auditing purposes, because Requirement R1 conditions are intended to be
unchanged unless the Transmission Operator is otherwise notified, the Generator
Owner only needs to provide the documentation to the Transmission Operator one
time, or whenever the operating specifications change.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
For auditing purposes, if a PSS is in service but is not providing an active signal to the
AVR as described in Requirement R1, the disabled period does not count against the
Requirement R2 mandate to be in service except as otherwise allowed.
R2. Each Generator Operator shall have its PSS in service while synchronized, except
during any of the following: [Violation Risk Factor: Medium] [Time Horizon: Operating
Assessment]
Component failure
Testing of a Bulk Electric System Element affecting or affected by the PSS
Maintenance
As agreed upon by the Generator Operator and the Transmission Operator
A PSS that is out of service for less than 30 minutes does not create a violation
of this Requirement, regardless of cause.
M2. Each Generator Operator will have documentation of each claimed exception
specified in Requirement R2. Documentation may include, but is not limited to:
A written explanation covering the bulleted exception that describes the
circumstances of the exception as allowed in Requirement R2.
Documented evidence that the Generator Operator and the Transmission
Operator agreed the PSS would not be operating during a specified set of
circumstances, where the exception is claimed under the last bullet of
Requirement R2.
For auditing purposes, the presumption is that the PSS was in service unless otherwise
exempted in Requirement R2. Evidence need only be provided to prove the
circumstances during which the PSS was not in service for periods in excess of 30
minutes.
R3. Each Generator Owner shall tune its PSS to meet the following inter‐area mode
criteria, except as specified in Requirement R3, Part 3.5 below: [Violation Risk Factor:
Medium] [Time Horizon: Operating Assessment]
3.1. PSS shall be set to provide the measured, simulated, or calculated compensated
Vt/Vref frequency response of the excitation system and synchronous machine
such that the phase angle will not exceed ± 30 degrees through the frequency
range from 0.2 Hertz to the lesser of 1.0 Hertz or the highest frequency at which
the phase of the Vt/Vref frequency response does not exceed 90 degrees.
3.2. PSS output limits shall be set to provide at least ±5% of the synchronous
machine’s nominal terminal voltage.
3.3. PSS gain shall be set to between 1/3 and 1/2 of maximum practical gain.
3.4. PSS washout time constant shall be no greater than 30 seconds.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
3.5. Units that have an excitation system or PSS that is incapable of meeting the
tuning requirements of Requirement R3 are exempt from Requirement R3 until
the voltage regulator is either replaced or retrofitted such that the PSS becomes
capable of meeting the tuning requirements.
M3. Each Generator Owner will have documented evidence that its PSS was tuned to
meet the specifications of Requirement R3.
If the exception under Requirement R3, Part 3.5, is claimed, the Generator Owner will
have documented evidence describing: 1) the conditions that render the PSS incapable
of meeting the tuning requirements, and 2) the date the voltage regulator was last
replaced or retrofitted.
R4. Each Generator Owner shall install and complete start‐up testing of a PSS on its
generator within 180 days of either of the following events: [Violation Risk Factor:
Medium] [Time Horizon: Operational Assessment]
The Generator Owner connects a generator to the BES, after achieving
Commercial Operation, and after the Effective Date of this standard.
The Generator Owner replaces the voltage regulator on its existing excitation
system, after achieving Commercial Operation for its generator that is
connected to the BES, and after the Effective Date of this standard.
M4. Each Generator Owner will have evidence that it installed and completed start‐up
testing of a PSS on its generator within 180 days of either of the conditions described
in Requirement R4, and when those conditions occur after the Effective Date of this
standard.
For auditing purposes The first bullet of Requirement R4, bullet one only applies to
equipment on its initial (first energization) connection to the BES.
R5. Each Generator Owner shall repair or replace a PSS within 24 months of that PSS
becoming incapable of meeting the tuning specifications stated in Requirement R3.
[Violation Risk Factor: Medium] [Time Horizon: Operational Assessment]
M5. Each Generator Owner will have evidence that it repaired or replaced its PSS within
24 months of that PSS becoming incapable of meeting the tuning specifications of
Requirement R3. Evidence may include, but is not limited to, documentation of the
date the PSS became incapable of meeting the Requirement R3 tuning specifications,
and the date the PSS was returned to service, demonstrating that the span of time
between the two events was less than 24 months.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
C. Compliance
C. Compliance
1. Compliance Monitoring Process
1.1 Compliance Enforcement Authority
: “Compliance Enforcement Authority” means NERC or the Regional Entity, or any entity
as otherwise designated by an Applicable Governmental Authority, in their
respective roles of monitoring and/or enforcing compliance with mandatory and
enforceable Reliability Standards in their respective jurisdictions.
1.2 Compliance Monitoring and Assessment Processes
Compliance Audits
Self‐Certifications
Spot Checking
Compliance Investigations
Self‐Reporting
Complaints
1.3 . Evidence Retention
: The following evidence retention periodsperiod(s) identify the period of time an entity
is required to retain specific evidence to demonstrate compliance. For instances
where the evidence retention period specified below is shorter than the time since
the last audit, the Compliance Enforcement Authority may ask an entity to provide
other evidence to show that it was compliant for the full ‐time period since the last
audit.
The applicable entity shall keep data or evidence to show compliance as identified
below unless directed by its Compliance Enforcement Authority to retain specific
evidence for a longer period of time as part of an investigation.
Each Generator Operator shall keep evidence for all Requirements of the
document for a period of three years plus calendar current.
1.4 Additional Compliance Information
None
D. Regional Differences
None
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Attachment DB
Table of Compliance Elements
1.3 Compliance Monitoring and Enforcement Program: As defined in the NERC Rules of
Procedure, “Compliance Monitoring and Enforcement Program” refers to the
identification of the processes that will be used to evaluate data or information for
the purpose of assessing performance or outcomes with the associated Reliability
Standard.
Page 5 of 14
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
R
Violation Severity Levels
Lower VSL
R1 NA
Moderate VSL
High VSL
Severe VSL
NA
NA
The Generator Owner failed to
provide its PSS operating
specifications to the
Transmission Operator as
required in Requirement R1.
R2 Each Generator Operator not
having its PSS in service while
synchronized in accordance with
Requirement R2, for more than 30
minutes but less than 60 minutes.
Each Generator Operator
not having its PSS in service
while synchronized in
accordance with
Requirement R2, for more
than 60 minutes but less
than 120 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 120 minutes but
less than 180 minutes.
Each Generator Operator not
having its PSS in service while
synchronized in accordance
with Requirement R2, for
more than 180 minutes.
R3 The Generator Owner’s PSS failed
to meet any of the required
performances in Requirement R3,
two times or fewer during the
audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, three times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, four times
during the audit period.
The Generator Owner’s PSS
failed to meet any of the
required performances in
Requirement R3, five times or
more during the audit period.
R4 NA
NA
NA
The Generator Owner failed to
install on its generator a PSS,
as required in Requirement R4.
R5 NA
NA
NA
The Generator Owner failed to
repair or replace a non‐
operational PSS as required in
Requirement R5.
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VAR‐501‐WECC‐43.1 – Power System Stabilizer
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
Page 8 of 14
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VAR‐501‐WECC‐3.14 – Power System Stabilizer
D. Regional Variances
None.
E. Associated Documents
None.
Version History
Version
Date
1
April 16, 2008
1
October 28, 2008
Action
Permanent Replacement
Standard for VAR‐STD‐002b‐1
Adopted by NERC Board of
Trustees
Change Tracking
1
April 21, 2011
FERC Order issued approving
VAR‐
501‐WECC‐1 (FERC approval
effective June 27, 2011;
Effective Date July 1, 2011)
2
November 13, 2014
Adopted by NERC Board of
Trustees
2
March 3, 2015
FERC letter order approved
VAR‐501‐WECC‐2
3
February 9, 2017
Adopted by NERC Board of
Trustees
3
April 28, 2017
FERC letter order approved
VAR‐501‐WECC‐3
3.1
August 10, 2017
Adopted by the NERC Board of
Trustees
Errata
3.1
TBDSeptember 26,
2017
TBDFERC letter order issued
approving VAR‐501‐WECC‐3.1
4
December 6, 2022
WECC Standards Committee
accepted a “no change “
recommendation followed by
Non‐substantive
changes were
approved by the
Page 9 of 14
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐3.14 – Power System Stabilizer
an information‐only filing to
NERC.
WECC Standards
Committee as
allowed in the WECC
Reliability Standards
Development
Procedures. An
information‐only
filing provided to
NERC reflects the
following: 1) updates
to the template and
syntax, 2) removal of
stale‐dated language
from the Effective
Date, 3) deletion of
“For auditing
purposes of…” from
M4, 4) in the
Guidance section,
“dampen” was
replaced with
“damp”, and syntax
was addressed
deleting “still”, “of
those”, “of the”, and
“to ensure” was
replaced with
“ensuring”, and
“wash out” was
replaced with
“washout.”
Page 10 of 14
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐3.14 – Power System Stabilizer
Guideline and Technical Basis
PSS systems are used to minimize real power oscillations by rapidly adjusting the field of the
generator to dampendamp the low‐frequency oscillations.
It is necessary for large numbers of PSS devices to be in operation in the Western
Interconnection to provide the required system damping while still allowing for some of these
units to be out of service whenever necessary.
Mandate to Install a PSS
Nothing in this Regional Reliability Standard (RSS) should be construed to require installation of
a PSS solely because a PSS is not currently installed as of the Effective Date of this RRS. Rather,
installation is only mandated on the occurrence of either of the triggering eventsevent
described in Requirement R4, Bullet 1 or Bullet 2, after the Effective Date of the RRS.
It should be noted that a PSS is neither Transmission nor generation.
Requirement R1
Requirement R1 addresses normal operating conditions.
Requirement R1 recognizes that PSS systems have varying states, such as on, off, active, and
non‐active. As long as the PSS is operating in accordance with the documentation provided to
the Transmission Operator, this is not considered a status change for purposes of this
standardStandard.
This Requirement eliminates the requirement to count hours as required in the previous
version of this standardStandard while also allowing the Generator Owner to create a unit‐
specific operating plan.
The intent of Requirement R1 is to provide the Transmission Operator, the PSS operating zone
in which the PSS is “active” providing damping to the power system. Some PSS may be
programmed to become “active” at a specified megawatt loading level and above while others
may be programmed to be “active” in a particular band of megawatt loading levels and are
“non‐active” only when passing through the “rough zone” or some other band. A “rough zone”
is a megawatt loading band in which the generator‐turbine system could contribute to system
instability.
Requirement R2
This Requirement only applies when the PSS is out of service for a period greater than 30
minutes.
Unlike Requirement R1, Requirement R2 addresses exceptions to normal operation.
Page 11 of 14
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐3.14 – Power System Stabilizer
The intent of Requirement R2 is to remove the previous requirement to log hours for PSS in
service. In this standard’sStandard’s previous version, the logged hours were totaled quarterly
to meet the 98% in‐service requirement. Instead of documenting the number of hours
excluded, this Requirement simplifies the process by allowing the Generator Operator to
communicate to the Transmission Operator the circumstances that render the PSS unavailable
to the Transmission Operator (such as component failure, maintenance, and testing).
Requirement R3
Nothing in this RSS should be construed to mandate the design criteria for the equipment used
to produce the tuning output of the PSS. Rather, Requirement R3 is intended to address the
design criteria for the tuning output of the PSS.
Unlike the language in Requirement R5 that looks backward to address units that were once
operating but are no longer capable of operating, Requirement R3 looks forward, requiring that
units be tuned to the specified parameters.
The PSS transfer function should compensate the phase characteristics of the generator,
exciter, and power (GEP) system transfer function so the compensated transfer function
((PSS(s) * GEP(s)) has a phase characteristic of ± 30 degrees in the frequency range.
The GEP(s) transfer function is a theoretical transfer function, and its phase characteristic
cannot be directly measured during field tests (only via simulation). Thus, the Requirement
recognizes the practical approach of measuring the frequency response between voltage
reference set point and terminal voltage (Et/Vref) and using the phase characteristic of such
frequency response as being the phase characteristic of GEP(s). The phase characteristic of
Et/Vref is a better approximation to the phase characteristic of GEP(s) when the frequency
response Et/Vref is obtained with the generator synchronized to the grid at its minimum stable
power output.
In an effort to allow for reasonable wash‐outwashout time constants, the Requirement
specifies 0.2 Hz as the applicable threshold. The 0.2 Hz threshold more closely aligns with the
observed oscillation frequencies.
A properly tuned PSS should provide positive damping to the local mode of oscillation, which
typically has a frequency higher than 1.0 Hz.
This Requirement modifies the requirement associated with the adjustment of the PSS gain.
The standard no longer defines the PSS gain in terms of gain margin but instead requires the
final PSS gain to be between 1/3 (10 dB) and 1/2 (6 dB) of the maximum practical gain that
could be achieved during PSS commissioning. The maximum practical gain might be associated
with the excessive noise or raised higher‐frequency oscillations in the closed loop response
(exciter mode) or any other form if there is inadequate closed‐loop performance, as
determined during PSS commissioning. It is now part of Measure M3 to show the field test
results that led to the determination of the maximum practical gain.
Page 12 of 14
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐3.14 – Power System Stabilizer
Requirement R4
Requirement R4 requires a Generator Owner to install a PSS on new applicable units or when
excitation systems are replaced or retrofitted on existing applicable units. This Requirement
applies to new excitation systems and not to existing systems that do not have PSS. The
Requirement also allows a reasonable amount of time for the commissioning of new PSS.
Requirement R5
Unlike the language in Requirement R3 that looks forward to ensureensuring that a unit is
tuned, Requirement R5 looks backward. Specifically, the language in Requirement R5,
“becoming incapable,” indicates the unit was previously capable of meeting the tuning
requirements in Requirement R3, but is no longer capable. Restated, Requirement R5 addresses
units that were previously working but are now no longer working.
The intent of Requirement R5 is to remove the “tiered” approach to PSS repair/replacement
following a failure. A simple, streamlined approach to allow the Generator Owner sufficient
time to repair or replace a broken PSS has been written. Consideration has been given for the
need to procure parts or new equipment, schedule an equipment/unit outage, and install and
test the repaired or replaced PSS. It is recognized that in some instances, it may require
(1) replacement of an AVR, and (2) the existence of a PSS, or both the AVR and the PSS may
need to be replaced to achieve a functioning system.
The 24‐month time frame is sufficient to return a functional, operating PSS to service.
Page 13 of 14
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
VAR‐501‐WECC‐3.14 – Power System Stabilizer
* FOR INFORMATIONAL PURPOSES ONLY *
Enforcement Dates: Standard VAR‐501‐WECC‐3 — Power System Stabilizer
United States
Standard
Requirement
Enforcement Date
Inactive Date
VAR‐501‐WECC‐3
TBD
TBD
Page 14 of 14
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Unofficial Comment Form
Regional Reliability Standard
VAR-501-WECC-4
DO NOT use this form for submitting comments. Use the electronic form to submit comments on the
proposed modifications to Regional Reliability Standard, VAR-501-WECC-4 (Power System Stabilizer).
The electronic form must be submitted by 8 p.m. Eastern, Friday, September 29, 2023.
Documents and information about this project are available on the WECC’s Standards page. If you have
questions, contact Reliability Standards Analyst, Kimberlin Harris (via email) or at (404) 446-9794.
Background Information
The WECC Regional Reliability Standard Drafting Team ensures each Regional Reliability Standard
undergoes a substantive review at least once every five years. During the most recent review, the
following changes to WECC’s Regional Reliability Standard VAR-501-WECC-3.1 Power System Stabilizer
were proposed:
1. Updates to the document template, numbering, and template sections as provided by NERC
2. Removal of stale-dated verbiage included in the Effective Date
3. Removal of the redundant phrase, “[F]or auditing purposes….” From Measure M4
4. Updates to syntax
5. Correction of “[s]tandard” to “[S]tandard”
6. Correction of “dampen” to “damp” in the Rationale and Guidance section
The WECC Board of Directors approved the proposed regional standard on June 14, 2023.
NERC Criteria for Developing or Modifying a Regional Reliability Standard
Each regional difference (i.e. Regional Reliability Standard or Variance) shall be: (1) is more stringent than
the continent-wide Reliability Standard, including a regional difference that addresses matters that the
continent-wide reliability standard does not; or (2) necessitated by a physical difference in the bulk power
system. Regional Reliability Standards and Variances shall provide for as much uniformity as possible with
Reliability Standards across the interconnected bulk power system of the North American continent.
Regional Reliability Standards and Variances, when approved by FERC and applicable authorities in Mexico
and Canada, shall be made part of the body of NERC Reliability Standards and shall be enforced upon all
applicable Bulk Power System owners, operators, and users within the applicable area, regardless of
membership in the region.
The approval process for a proposed Regional Reliability Standard or Variance, or the retirement of an
existing standard or Variance, requires NERC to publicly notice and request comment. Comments shall be
RELIABILITY | RESILIENCE | SECURITY
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
permitted only on the following criteria (technical aspects of the standard are vetted through the regional
standards development process):
Unfair or Closed Process – The Regional Reliability Standard was not developed in a fair and open process
that provided an opportunity for all interested parties to participate. Although a NERC-approved Regional
Reliability Standards development procedure shall be presumed to be fair and open, objections could be
raised regarding the implementation of the procedure.
Adverse Reliability or Commercial Impact on Other Interconnections – The Regional Reliability Standard
would have a significant adverse impact on reliability or commerce in other interconnections.
Deficient Standard – The Regional Reliability Standard fails to provide a level of reliability of the Bulk
Power System such that the Regional Reliability Standard would be likely to cause a serious and
substantial threat to public health, safety, welfare, or national security.
Adverse Impact on Competitive Markets within the Interconnection – The Regional Reliability Standard
would create a serious and substantial burden on competitive markets within the interconnection that is
not necessary for reliability.
Questions
1. Do you agree the proposed Regional Reliability Standard was developed in a fair and open process,
using the associated Regional Reliability Standards Development Procedure?
Yes
No
Comments:
2. Does the proposed Regional Reliability Standard pose an adverse impact to reliability or commerce
in a neighboring region or interconnection?
Yes
No
Comments:
3. Does the proposed Regional Reliability Standard pose a serious and substantial threat to public
health, safety, welfare, or national security?
Yes
No
Comments:
Unofficial Comment Form
VAR-501-WECC-4 | August 16-September 29, 2023
2
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
4. Does the proposed Regional Reliability Standard pose a serious and substantial burden on
competitive markets within the interconnection that is not necessary for reliability?
Yes
No
Comments:
5. Does the proposed Regional Reliability Standard meet at least one of the following criteria?
•
The proposed Regional Reliability Standard has more specific criteria for the same
requirements covered in a continent-wide standard.
•
The proposed Regional Reliability Standard has requirements that are not included in the
corresponding continent-wide standard.
•
The proposed regional difference is necessitated by a physical difference in the Bulk Power
System.
Yes
No
Comments:
Unofficial Comment Form
VAR-501-WECC-4 | August 16-September 29, 2023
3
Document
Accession
Dashboard (/)
NERC Balloting
Tool#:
(/) 20231215-5332
Date: Comment
12/15/2023
Users Filed
Ballots
Forms
Login (/Users/Login) / Register (/Users/Register)
REAL-TIME COMMENTS
This comment form is no longer interactive because the comment period is closed.
Regional Reliability Standard (WECC) | VAR-501-WECC-4 – Power System
Stabilizer
Description:
Start Date: 08/16/2023
End Date: 09/29/2023
Associated Ballots:
Ballot Name
Filter:
Project
Standard
None
Pool Open
Pool Close
Voting Start
Voting End
Filter
Q:
1. Do you agree the proposed Regional Reliability Standard was developed in a fair and open process,
using the associated Regional Reliability Standards Development Procedure?
Hot Answers
A: Yes (.a-b-78564)
Israel Perez, On Behalf of: Salt River Project - WECC - Segments 1, 3, 5, 6
-0 -0
A: Yes (.a-b-78559)
ACES Collaborators, Segment(s) 1, 9/29/2023
-0 -0
Other Answers
A: Yes (.a-b-78351)
BC Hydro, Segment(s) 3, 5, 1, 12/18/2018
-0 -0
A: Yes (.a-b-78356)
Andrea
On Behalf
of: Bonneville
Power Administration, WECC, Segments 1, 5, 6
© 2023 - NERC
VerJessup,
4.2.1.0 Machine
Name:
ERODVSBSWB01
- Accession
0 -0
Document
#: 20231215-5332
Filed Date: 12/15/2023
A: Yes (.a-b-78370)
Robert Follini, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: Yes (.a-b-78380)
Glen Farmer, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: Yes (.a-b-78445)
Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5
-0 -0
A: Yes (.a-b-78526)
None
Daniela Atanasovski, On Behalf of: APS - Arizona Public Service Co., , Segments 1, 3, 5, 6
-0 -0
A: Yes (.a-b-78549)
Mike Magruder, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
Q:
2. Does the proposed Regional Reliability Standard pose an adverse impact to reliability or commerce
in a neighboring region or interconnection?
Hot Answers
A: No (.a-b-78565)
Israel Perez, On Behalf of: Salt River Project - WECC - Segments 1, 3, 5, 6
-0 -0
A: No (.a-b-78560)
ACES Collaborators, Segment(s) 1, 9/29/2023
-0 -0
© 2023 - NERC Ver 4.2.1.0 Machine Name: ERODVSBSWB01
Other Answers
Document
Accession #: 20231215-5332
Filed Date: 12/15/2023
A: No (.a-b-78352)
BC Hydro, Segment(s) 3, 5, 1, 12/18/2018
-0 -0
A: No (.a-b-78357)
Andrea Jessup, On Behalf of: Bonneville Power Administration, WECC, Segments 1, 5, 6
-0 -0
A: No (.a-b-78371)
Robert Follini, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78381)
NA
Glen Farmer, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78446)
Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5
-0 -0
A: No (.a-b-78527)
None
Daniela Atanasovski, On Behalf of: APS - Arizona Public Service Co., , Segments 1, 3, 5, 6
-0 -0
A: No (.a-b-78550)
Mike Magruder, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
Q:
3. Does the proposed Regional Reliability Standard pose a serious and substantial threat to public
health, safety, welfare, or national security?
© 2023 - NERC Ver 4.2.1.0 Machine Name: ERODVSBSWB01
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Hot Answers
A: No (.a-b-78566)
Israel Perez, On Behalf of: Salt River Project - WECC - Segments 1, 3, 5, 6
-0 -0
A: No (.a-b-78561)
ACES Collaborators, Segment(s) 1, 9/29/2023
-0 -0
Other Answers
A: No (.a-b-78353)
BC Hydro, Segment(s) 3, 5, 1, 12/18/2018
-0 -0
A: No (.a-b-78358)
Andrea Jessup, On Behalf of: Bonneville Power Administration, WECC, Segments 1, 5, 6
-0 -0
A: No (.a-b-78372)
Robert Follini, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78382)
Glen Farmer, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78447)
Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5
-0 -0
A: No (.a-b-78528)
None
Daniela Atanasovski, On Behalf of: APS - Arizona Public Service Co., , Segments 1, 3, 5, 6
-0 -0
© 2023 - NERC Ver 4.2.1.0 Machine Name: ERODVSBSWB01
Document
#: 20231215-5332
A:Accession
No (.a-b-78551)
Filed Date: 12/15/2023
Mike Magruder, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
Q:
4. Does the proposed Regional Reliability Standard pose a serious and substantial burden on
competitive markets within the interconnection that is not necessary for reliability?
Hot Answers
A: No (.a-b-78567)
Israel Perez, On Behalf of: Salt River Project - WECC - Segments 1, 3, 5, 6
-0 -0
A: No (.a-b-78562)
ACES Collaborators, Segment(s) 1, 9/29/2023
-0 -0
Other Answers
A: No (.a-b-78354)
BC Hydro, Segment(s) 3, 5, 1, 12/18/2018
-0 -0
A: No (.a-b-78359)
Andrea Jessup, On Behalf of: Bonneville Power Administration, WECC, Segments 1, 5, 6
-0 -0
A: No (.a-b-78373)
Robert Follini, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78383)
Glen Farmer, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78448)
© 2023 - NERC Ver 4.2.1.0 Machine Name: ERODVSBSWB01
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5
-0 -0
A: No (.a-b-78529)
None
Daniela Atanasovski, On Behalf of: APS - Arizona Public Service Co., , Segments 1, 3, 5, 6
-0 -0
A: No (.a-b-78552)
Mike Magruder, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
Q:
5. Does the proposed Regional Reliability Standard meet at least one of the following criteria?
The proposed Regional Reliability Standard has more specific criteria for the same requirements
covered in a continent-wide standard.
The proposed Regional Reliability Standard has requirements that are not included in the
corresponding continent-wide standard.
The proposed regional difference is necessitated by a physical difference in the Bulk Power System.
Hot Answers
A: Yes (.a-b-78568)
While there are regional and physical differences, the changes proposed are mainly grammatical and all are minor.
Israel Perez, On Behalf of: Salt River Project - WECC - Segments 1, 3, 5, 6
-0 -0
A: Yes (.a-b-78563)
Thank you for the opportunity to comment.
ACES Collaborators, Segment(s) 1, 9/29/2023
-0 -0
Other Answers
A: Yes (.a-b-78355)
BC Hydro, Segment(s) 3, 5, 1, 12/18/2018
-0 -0
© 2023 - NERC
Machine Name: ERODVSBSWB01
A:Ver
Yes4.2.1.0
(.a-b-78360)
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Andrea Jessup, On Behalf of: Bonneville Power Administration, WECC, Segments 1, 5, 6
-0 -0
A: No (.a-b-78374)
Robert Follini, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: No (.a-b-78384)
Glen Farmer, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
A: Yes (.a-b-78449)
Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5
-0 -0
A: Yes (.a-b-78530)
None
Daniela Atanasovski, On Behalf of: APS - Arizona Public Service Co., , Segments 1, 3, 5, 6
-0 -0
A: No (.a-b-78553)
Mike Magruder, On Behalf of: Avista - Avista Corporation, , Segments 1, 3, 5
-0 -0
© 2023 - NERC Ver 4.2.1.0 Machine Name: ERODVSBSWB01
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Comment Report
Project Name:
Regional Reliability Standard (WECC) | VAR-501-WECC-4 – Power System Stabilizer
Comment Period Start Date:
8/16/2023
Comment Period End Date:
9/29/2023
Associated Ballots:
There were 9 sets of responses, including comments from approximately 14 different people from approximately 9 companies
representing 4 of the Industry Segments as shown in the table on the following pages.
Document Accession #: 20231215-5332
Questions
Filed Date: 12/15/2023
1. Do you agree the proposed Regional Reliability Standard was developed in a fair and open process, using the associated Regional
Reliability Standards Development Procedure?
2. Does the proposed Regional Reliability Standard pose an adverse impact to reliability or commerce in a neighboring region or
interconnection?
3. Does the proposed Regional Reliability Standard pose a serious and substantial threat to public health, safety, welfare, or national
security?
4. Does the proposed Regional Reliability Standard pose a serious and substantial burden on competitive markets within the interconnection
that is not necessary for reliability?
5. Does the proposed Regional Reliability Standard meet at least one of the following criteria?
•
•
•
The proposed Regional Reliability Standard has more specific criteria for the same requirements covered in a continent-wide
standard.
The proposed Regional Reliability Standard has requirements that are not included in the corresponding continent-wide standard.
The proposed regional difference is necessitated by a physical difference in the Bulk Power System.
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Organization
Name
Segment(s)
Region
Group Name Group Member
Name
Name
BC Hydro and Adrian
Power
Andreoiu
Authority
ACES Power
Marketing
1,3,5
Jodirah Green 1
WECC
BC Hydro
Group
Member
Organization
Group
Member
Segment(s)
Group Member
Region
Hootan Jarollahi BC Hydro and 3
Power
Authority
WECC
Helen Hamilton
Harding
BC Hydro and 5
Power
Authority
WECC
Adrian Andreoiu BC Hydro and 1
Power
Authority
WECC
MRO,RF,SERC,Texas ACES
Bob Soloman
RE,WECC
Collaborators
Kris Carper
Hoosier
Energy
Electric
Cooperative
1
Arizona
1
Electric Power
Cooperative,
Inc.
RF
WECC
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
1. Do you agree the proposed Regional Reliability Standard was developed in a fair and open process, using the associated Regional
Reliability Standards Development Procedure?
Daniela Atanasovski - APS - Arizona Public Service Co. - 1,3,5,6
Answer
Yes
Document Name
Comment
None
Likes
0
Dislikes
0
Response
Adrian Andreoiu - BC Hydro and Power Authority - 1,3,5, Group Name BC Hydro
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
0
Response
Andrea Jessup - Bonneville Power Administration - 1,5,6 - WECC
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
0
Response
Robert Follini - Avista - Avista Corporation - 1,3,5
Answer
Document Accession #: 20231215-5332
Document Name
Yes
Filed Date: 12/15/2023
Comment
Likes
0
Dislikes
0
Response
Glen Farmer - Avista - Avista Corporation - 1,3,5
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
0
Response
Richard Jackson - U.S. Bureau of Reclamation - 1,5
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
0
Response
Mike Magruder - Avista - Avista Corporation - 1,3,5
Answer
Yes
Document Name
Comment
Likes
0
Dislikes 0
Document Accession #: 20231215-5332
Response
Filed Date: 12/15/2023
Jodirah Green - ACES Power Marketing - 1 - WECC, Group Name ACES Collaborators
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
0
Response
Israel Perez - Salt River Project - 1,3,5,6 - WECC
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
Response
0
2. Does
the proposed
Regional Reliability Standard
pose an
adverse impact to reliability or commerce in a neighboring region or
Document
Accession
#: 20231215-5332
Filed Date:
12/15/2023
interconnection?
Daniela Atanasovski - APS - Arizona Public Service Co. - 1,3,5,6
Answer
No
Document Name
Comment
None
Likes
0
Dislikes
0
Response
Glen Farmer - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
NA
Likes
0
Dislikes
0
Response
Israel Perez - Salt River Project - 1,3,5,6 - WECC
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Jodirah Green - ACES Power Marketing - 1 - WECC, Group Name ACES Collaborators
Answer
Document Accession #: 20231215-5332
Document Name
No
Filed Date: 12/15/2023
Comment
Likes
0
Dislikes
0
Response
Mike Magruder - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Richard Jackson - U.S. Bureau of Reclamation - 1,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Robert Follini - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes 0
Document Accession #: 20231215-5332
Response
Filed Date: 12/15/2023
Andrea Jessup - Bonneville Power Administration - 1,5,6 - WECC
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Adrian Andreoiu - BC Hydro and Power Authority - 1,3,5, Group Name BC Hydro
Answer
No
Document Name
Comment
Likes
0
Dislikes
Response
0
3. Does
the proposed
Regional Reliability Standard
pose a12/15/2023
serious and substantial threat to public health, safety, welfare, or national
Document
Accession
#: 20231215-5332
Filed Date:
security?
Daniela Atanasovski - APS - Arizona Public Service Co. - 1,3,5,6
Answer
No
Document Name
Comment
None
Likes
0
Dislikes
0
Response
Adrian Andreoiu - BC Hydro and Power Authority - 1,3,5, Group Name BC Hydro
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Andrea Jessup - Bonneville Power Administration - 1,5,6 - WECC
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Robert Follini - Avista - Avista Corporation - 1,3,5
Answer
Document Accession #: 20231215-5332
Document Name
No
Filed Date: 12/15/2023
Comment
Likes
0
Dislikes
0
Response
Glen Farmer - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Richard Jackson - U.S. Bureau of Reclamation - 1,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Mike Magruder - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes 0
Document Accession #: 20231215-5332
Response
Filed Date: 12/15/2023
Jodirah Green - ACES Power Marketing - 1 - WECC, Group Name ACES Collaborators
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Israel Perez - Salt River Project - 1,3,5,6 - WECC
Answer
No
Document Name
Comment
Likes
0
Dislikes
Response
0
4. Does
the proposed
Regional Reliability Standard
pose a12/15/2023
serious and substantial burden on competitive markets within the interconnection
Document
Accession
#: 20231215-5332
Filed Date:
that is not necessary for reliability?
Daniela Atanasovski - APS - Arizona Public Service Co. - 1,3,5,6
Answer
No
Document Name
Comment
None
Likes
0
Dislikes
0
Response
Israel Perez - Salt River Project - 1,3,5,6 - WECC
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Jodirah Green - ACES Power Marketing - 1 - WECC, Group Name ACES Collaborators
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Mike Magruder - Avista - Avista Corporation - 1,3,5
Answer
Document Accession #: 20231215-5332
Document Name
No
Filed Date: 12/15/2023
Comment
Likes
0
Dislikes
0
Response
Richard Jackson - U.S. Bureau of Reclamation - 1,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Glen Farmer - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Robert Follini - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes 0
Document Accession #: 20231215-5332
Response
Filed Date: 12/15/2023
Andrea Jessup - Bonneville Power Administration - 1,5,6 - WECC
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Adrian Andreoiu - BC Hydro and Power Authority - 1,3,5, Group Name BC Hydro
Answer
No
Document Name
Comment
Likes
0
Dislikes
Response
0
5. Does
the proposed
Regional Reliability Standard
meet at12/15/2023
least one of the following criteria?
Document
Accession
#: 20231215-5332
Filed Date:
•
•
•
The proposed Regional Reliability Standard has more specific criteria for the same requirements covered in a continent-wide
standard.
The proposed Regional Reliability Standard has requirements that are not included in the corresponding continent-wide standard.
The proposed regional difference is necessitated by a physical difference in the Bulk Power System.
Robert Follini - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Glen Farmer - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
0
Response
Mike Magruder - Avista - Avista Corporation - 1,3,5
Answer
No
Document Name
Comment
Likes
0
Dislikes
Response
0
Daniela Atanasovski - APS - Arizona Public Service Co. - 1,3,5,6
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Answer
Yes
Document Name
Comment
None
Likes
0
Dislikes
0
Response
Jodirah Green - ACES Power Marketing - 1 - WECC, Group Name ACES Collaborators
Answer
Yes
Document Name
Comment
Thank you for the opportunity to comment.
Likes
0
Dislikes
0
Response
Israel Perez - Salt River Project - 1,3,5,6 - WECC
Answer
Yes
Document Name
Comment
While there are regional and physical differences, the changes proposed are mainly grammatical and all are minor.
Likes
0
Dislikes
0
Response
Adrian Andreoiu - BC Hydro and Power Authority - 1,3,5, Group Name BC Hydro
Answer
Yes
Document Name
Document Accession #: 20231215-5332
Comment
Likes
Filed Date: 12/15/2023
0
Dislikes
0
Response
Andrea Jessup - Bonneville Power Administration - 1,5,6 - WECC
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
0
Response
Richard Jackson - U.S. Bureau of Reclamation - 1,5
Answer
Yes
Document Name
Comment
Likes
0
Dislikes
Response
0
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Response to Comments
Posting 1—45-Day at NERC
August 16 through September 29, 2023
WECC-0148 VAR-501-WECC-4
Power System Stabilizer
Information Only Filing
Posting 1—45-Day NERC
The WECC-0148 VAR-501-WECC-4, Power System Stabilizer Drafting Team (DT) thanks everyone who
submitted comments on the proposed project. WECC-0148 is an information-only filing proposing no
Substantive changes. 1
Posting
This project was posted for comment by NERC from August 16, 2023, through September 29, 2023.
NERC distributed notice for the posting on August 16, 2023.
NERC asked stakeholders to provide feedback on the proposed project through a standardized
electronic template.
NERC reported there “were 9 sets of responses, including comments from approximately 14 different
people from approximately 9 companies representing 4 of the Industry Segments.”
After review of the NERC-provided document, WECC found responses from seven organizations
(some with member organization subcomponents), and 13 persons identified in the following Table of
Respondents.
Location of Comments
All comments provided to WECC by NERC can be reviewed in their original format on the WECC-0148
project page under the “Submit and Review Comments” accordion.
Changes in Response to Comment
After consideration of all comments received, no further changes were made to this project.
The terms Substantive and Non-Substantive are defined terms found in the WECC Relibaility Standards
Development Procedures.
https://www.wecc.org/Reliability/WECC%20Reliability%20Standards%20Development%20Procedures%20%20FERC%20Approved%2009-13-2021.pdf
1
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www.wecc.org
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Minority View
No minority views were raised.
Proposed Effective Date
The proposed Standard can be implemented immediately upon receipt of final regulatory approval.
Information Only—No Substantive Changes
This project represents an “Information Only” filing with no Substantive changes.
Per the WECC Relibaility Standards Development Procedures (Procedures), if no Substantive changes
are requested to a Regional Standard, no further due process is required. Specifically, WECC Board of
Directors (Board) approval is not required.
On July 11, 2022, a list 2 of proposed Non-Substantive changes was distributed to the Standards Email
List (SEL) inviting comments or concerns to be forwarded to WECC Standards staff. A redline and a
clean version of the project was posted on the WECC-0148, Posting 1 for Comment accordion. No
comments were received.
On July 16, 2022, WECC posted a letter 3 to the WSC informing the WSC of its scope and authority to
address an information only filing. The letter was published to the WECC-0148 home page on the
Posting 1 for Comment accordion.
On December 6, 2022, during a duly noticed WSC meeting, the WSC reviewed the letter from July 16,
2022, and was briefed on the WSC’s Procedural authority to approve the project with no further due
process, so long as all changes were deemed Non-Substantive.
The WSC concurred 4 that all proposed changes were Non-Substantive. Because the proposed changes
are all Non-Substantive, the WSC also concurred that neither a posting for comment, ballot, Board
approval, nor an Implementation Plan were required per the Procedures.
Table of Respondents
Organization
1
ACES Power Marketing (ACES)
Bob Soloman, Jodirah Green, Kris Carper
2
Arizona Public Service Company (APS)
Daniel Atanasovski
3
Avista Corporation
Glen Farmer, Mike Magruder, Robert Follini
https://www.wecc.org/Administrative/WECC-0148%20Notice%20of%20No%20Substantive%20Change.pdf
https://www.wecc.org/Reliability/WECC-0148%20VAR-501-WECC-3.1%20%20Letter%20to%20WSC%20Requesting%20Information%20Only%20Filing%20-%20FINAL.docx
4 https://www.wecc.org/Administrative/2022-0316%20WSC%20Proposed%20Meeting%20Minutes%20for%20approval%202022-12-06-2022%20%20FINAL%20FROM%20TECH.docx
2
3
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Organization
4
BC Hydro and Power Authority (BC)
Adrian Andreoiu, Helen Hamilton Harding,
Hootan Jarollahi
5
Bonneville Power Administration (BPA)
Andrea Jessup
6
Salt River Project (SRP)
Israel Perez
7
United States Bureau of Reclamation
Richard Jackson
(USB)
Contacts and Appeals
If you feel your comment has been omitted or overlooked, please contact W. Shannon Black, WECC
Consultant, at (503) 307-5782. In addition, there is a WECC Reliability Standards appeals process.
3
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Index to NERC-provided Questions, Comments, and Responses
Question
1) Do you agree the proposed Regional Reliability Standard was developed in a fair and open
process, using the associated Regional Reliability Standards Development Procedure?
2) Does the proposed Regional Reliability Standard pose an adverse impact to reliability or
commerce in a neighboring region or interconnection?
3) Does the proposed Regional Reliability Standard pose a serious and substantial threat to public
health, safety, welfare, or national security?
4) Does the proposed Regional Reliability Standard pose a serious and substantial burden on
competitive markets within the interconnection that is not necessary for reliability?
5) Does the proposed Regional Reliability Standard meet at least one of the following criteria
a. The proposed Regional Reliability Standard has more specific criteria for the same
requirements covered in a continent-wide standard.
b. The proposed Regional Reliability Standard has requirements that are not included in
the corresponding continent-wide standard.
c. The proposed regional difference is necessitated by a physical difference in the Bulk
Power System.
4
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 1—Do you agree the proposed Regional Reliability Standard was developed in a fair and
open process, using the associated Regional Reliability Standards Development Procedure?
Commenter
Comment or Response
ACES
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
Yes
Response
5
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
6
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 2— Does the proposed Regional Reliability Standard pose an adverse impact to
reliability or commerce in a neighboring region or interconnection?
Commenter
Comment or Response
ACES
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
7
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
8
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 3— Does the proposed Regional Reliability Standard pose a serious and substantial
threat to public health, safety, welfare, or national security?
Commenter
Comment or Response
ACES
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
9
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
10
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 4— Does the proposed Regional Reliability Standard pose a serious and substantial
burden on competitive markets within the interconnection that is not necessary for reliability?
Commenter
Comment or Response
ACES
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
No.
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
11
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BC
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
No
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
12
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
Comment Summary. For proposed changes and avenues forward, please see the preamble.
1) Question 5—Does the proposed Regional Reliability Standard meet at least one of the following
criteria:
d. The proposed Regional Reliability Standard has more specific criteria for the same
requirements covered in a continent-wide standard.
e.
The proposed Regional Reliability Standard has requirements that are not included in the
corresponding continent-wide standard.
f.
The proposed regional difference is necessitated by a physical difference in the Bulk Power
System.
Commenter
Comment or Response
ACES
Yes. Thank you for the opportunity to comment.
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
APS
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
Avista – Glen Farmer
No
Response
The WECC-0148 Drafting Team (DT) appreciates Avista’s negative response; however, Avista has failed to
explain their response, identify any issues, or suggest any proposed changes. As such, the DT can neither
identify nor remedy Avista’s concern.
Commenter
Comment or Response
Avista - Mike Magruder
No
Response
The WECC-0148 Drafting Team (DT) appreciates Avista’s negative response; however, Avista has failed to
explain their response, identify any issues, or suggest any proposed changes. As such, the DT can neither
identify nor remedy Avista’s concern.
Commenter
Comment or Response
Avista - Robert Follini
No
Response
13
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
WECC-0148 NERC 45-Day Posting
Response to Comments, Posting 1
The WECC-0148 Drafting Team (DT) appreciates Avista’s negative response; however, Avista has failed to
explain their response, identify any issues, or suggest any proposed changes. As such, the DT can neither
identify nor remedy Avista’s concern.
Commenter
Comment or Response
BC
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
BPA
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
SRP
Yes. While there are regional and physical differences, the
changes proposed are mainly grammatical and all are minor.
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
Commenter
Comment or Response
USB
Yes
Response
The WECC-0148 Drafting Team (DT) appreciates each respondent’s engagement in the Standards development
process.
14
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Exhibit C
Standard Dra�ing Team Roster for Project
WECC-0148 Power System Stabilizer
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment L
Drafting Team Roster
WECC-0148 VAR-501-WECC-4
Five-year Review
Drafting Team Roster
Below please find a brief biography for each member of the WECC-0148 VAR-501-WECC-4, Power
System Stabilizer, Five-year Review Drafting Team.
Name
Qualifications
Greg Anderson,
Mr. Anderson is the subject matter expert for generation and excitation
Southern
systems for the Southern California Edison Company. He has over 33
California Edison
years of experience in the utility industry, with responsibilities for
coordinating WECC testing of generation assets. He has been a WECC
participant since 1997 and a member of the Control Work Group since
2003.
Joel Anthes,
Pacific Gas and
Electric
Mr. Anthes is a Senior Electrical Engineer with Pacific Gas and Electric
Company’s Power Generation organization. Mr. Anthes has more than 16
years of experience in the electrical and power generation industries. Over
the past nine years, he has led the development of multiple technical
programs related to electrical generation and excitation system protection,
control system tuning and modeling, and generator electrical ratings. Mr.
Anthes is a registered professional engineer in the state of California and
plays an active role in the development of industry best practices and
regulatory standards for NERC. Recent experience includes:
•
Member of the drafting team for NERC Project 2020-02
Transmission-connected Dynamic Reactive Resources.
•
Power system stabilizer (PSS) tuning and validation.
•
Development of tools for numerical calculation of generator field
current. Performs generator heat runs to prove safe increase of
electrical rating beyond existing nameplate.
•
Development of program for dynamic modeling of generators,
voltage regulators, governors, and power system stabilizers.
Development of associated programs for NERC regulatory
compliance.
155 North 400 West | Suite 200 | Salt Lake City, Utah 84103
www .wecc.or g
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment L
•
Developed custom tools for determining generator electrical
characteristics, impedances, time constants, phase response, and
capability curves for synchronous generators. Oversees training of
other engineers in the proper implementation of these tools.
•
Commissions and tests excitation systems, voltage regulators, and
power system stabilizers.
•
Performs Root Cause Analyses using industry standard
methodologies for operational safety incidents and major
equipment failures.
•
Developed recommendations for corrective actions to effectively
prevent the recurrence of equipment failure and human
performance errors.
Shane Kronebusch,
L&S Electric, Inc.
Mr. Kronebusch is the Lead Electrical Engineer and subject matter expert
for generation and excitation systems for L&S Electric, Inc. He has over 31
years of experience in the utility industry, including:
•
Developing the LS-AES excitation system.
•
Designing, installing, and commissioning exciters and governors
across a wide range of units.
•
Performing of testing and model validation reports for NERC
MOD-025, -026, & -027.
•
Coordinating and preforming WECC testing of generation assets as
an employee of BC Hydro Generation Engineering and
Maintenance Services before joining L&S Electric, Inc. in 2010.
•
Participating as a member of the WECC Control Work Group since
2006 and drafting team member of WECC-0099/0107.
Matthew
Mr. McDonald is a Senior Electrical Engineer in the Technical Projects
McDonald, Arizona Engineering department with 15 years of experience in the utility industry.
Public Service
He holds a Bachelor of Science from Pennsylvania State University as well
as a professional engineering license. His expertise and experience include
the following:
•
13 years’ hands-on experience installing, troubleshooting,
commissioning, and tuning excitation systems and generator
protection relays.
•
Five years of experience performing generator, excitation, and PSS
model validation via simulation and live testing.
2
Document Accession #: 20231215-5332
Filed
Date: 12/15/2023
Attachment L
•
Excitation system subject matter expert for Arizona Public Service
for the past four years.
•
NERC/WECC compliance lead for VAR-501-3, PRC-19-2, PRC-002,
PRC-27-1 and PRC-25-2.
•
Other responsibilities and roles have included generator excitation
instructor, improvisational field testing, synchro-phasor and digital
fault recorder commissioning.
Kimberly Turco,
Ms. Turco has worked for Constellation Energy Generation (CEG) for 10
Constellation
years, with the last two years in NERC compliance and supporting ISO
Energy
compliance. CEG is actively involved in NERC’s Standards Under
Development process and would like to take this opportunity for direct
involvement in the review of VAR-501-WECC. Kim comes with a wide
background in energy and compliance that would be an asset in the
standards review process.
Kim’s background:
•
Worked as a subject matter expert in AESO in day-ahead bidding
and electronic transaction systems (ETS).
•
Drafted CEG’s Grande Prairie Generation generating station’s
Transmission Must Run Contract.
•
A barred attorney.
•
NERC compliance SME and compliance contact for CEG’s WECC
and Alberta generating facilities.
•
Lead on historical submittal of Automatic Voltage Regulator and
Power System Stabilizer Outage reporting.
Kim has the full support of CEG’s NERC Compliance Group and will be
able to dedicate the time and resources demanded of a member of the
Standards Drafting Team.
3
Document Accession #: 20231215-5332
Filed Date: 12/15/2023
Document Content(s)
NERC and WECC Joint Petition on VAR-501-WECC-4_final.pdf .................1
| File Type | application/pdf |
| Author | bryants |
| File Modified | 2024-05-02 |
| File Created | 2024-05-02 |