NERC Petition

UNITED STATES OF AMERICA
BEFORE THE
FEDERAL ENERGY REGULATORY COMMISSION
North American Electric Reliability
Corporation

)
)

Docket No. _________

PETITION OF THE
NORTH AMERICAN ELECTRIC RELIABILITY CORPORATION
FOR APPROVAL OF PROPOSED RELIABILITY STANDARD
PRC-025-2
Shamai Elstein
Senior Counsel
Lauren A. Perotti
Counsel
North American Electric Reliability Corporation
1325 G Street, N.W., Suite 600
Washington, D.C. 20005
(202) 400-3000
(202) 644-8099– facsimile
shamai.elstein@nerc.net
lauren.perotti@nerc.net
Counsel for the North American Electric
Reliability Corporation

March 16, 2018

TABLE OF CONTENTS
EXECUTIVE SUMMARY .................................................................................................... 2
NOTICES AND COMMUNICATIONS ................................................................................ 4
BACKGROUND ................................................................................................................. 4
A.

Regulatory Framework ..................................................................................................... 4

B.

NERC Reliability Standards Development Procedure ..................................................... 5

C.

Project 2016-04 Modifications to PRC-025-1 ................................................................. 6
JUSTIFICATION FOR APPROVAL.................................................................................. 7

A.

Revisions to Address Dispersed Power Producing Resources ......................................... 8

B.

Revisions to Address Non-Standard Relay Element Applications .................................. 9

C.

Revisions to Clarify Application Column of Table 1 .................................................... 10

D.

Revisions to Address Dependability of Protective Relays that Interconnect Generating
Facilities to the Transmission System............................................................................... 11

E.

Revisions to Address Use of Term “Pickup Setting” ..................................................... 12

F.

Miscellaneous Revisions to Attachment 1: Relay Settings ............................................ 12

G.

Revisions to PRC-025 Guidelines and Technical Basis ................................................ 13

H.

Enforceability of the Proposed Reliability Standard ...................................................... 13
EFFECTIVE DATE .............................................................................................................. 13
CONCLUSION .................................................................................................................. 16

Exhibit A

Proposed Reliability Standard PRC-025-2

Exhibit B

Implementation Plan

Exhibit C

Order No. 672 Criteria

Exhibit D

Analysis of Violation Risk Factors and Violation Severity Levels

Exhibit E

Summary of Development and Complete Record of Development

Exhibit F

Standard Drafting Team Roster

i

UNITED STATES OF AMERICA
BEFORE THE
FEDERAL ENERGY REGULATORY COMMISSION
North American Electric Reliability
Corporation

)
)

Docket No. ________

PETITION OF THE
NORTH AMERICAN ELECTRIC RELIABILITY CORPORATION
FOR APPROVAL OF PROPOSED RELIABILITY STANDARD
PRC-025-2
Pursuant to Section 215(d)(1) of the Federal Power Act (“FPA”) 1 and Section 39.5 2 of
the Federal Energy Regulatory Commission’s (“FERC” or “Commission”) regulations, the North
American Electric Reliability Corporation (“NERC”) 3 hereby submits for Commission approval
proposed Reliability Standard PRC-025-2 - Generator Relay Loadability. The PRC-025
Reliability Standard addresses setting load-responsive protective relays associated with
generation Facilities 4 at a level to prevent unnecessary tripping of generators during a system
disturbance for conditions that do not pose a risk of damage to the associated equipment.
Proposed Reliability Standard PRC-025-2 improves upon currently-effective Reliability Standard
PRC-025-1 by addressing certain relay setting application issues and by clarifying certain
terminology and references. NERC requests that the Commission approve the proposed
Reliability Standard (Exhibit A) and find that the proposed standard is just, reasonable, not
unduly discriminatory or preferential, and in the public interest. NERC also requests that the
Commission approve: (i) the associated Implementation Plan (Exhibit B); (ii) the associated

1

16 U.S.C. § 824o (2012).
18 C.F.R. § 39.5 (2017).
3
The Commission certified NERC as the electric reliability organization (“ERO”) in accordance with
Section 215 of the FPA on July 20, 2006. N. Am. Elec. Reliability Corp., 116 FERC ¶ 61,062 (2006).
4
Unless otherwise designated, capitalized terms shall have the meaning set forth in the Glossary of Terms
Used in NERC Reliability Standards (“NERC Glossary of Terms”), available at
http://www.nerc.com/files/Glossary_of_Terms.pdf.
2

1

Violation Risk Factors (“VRFs”) and Violation Severity Levels (“VSLs”), which remain
unchanged from PRC-025-1 (Exhibit D); and (iii) the retirement of currently-effective
Reliability Standard PRC-025-1.
As required by Section 39.5(a) 5 of the Commission’s regulations, this Petition presents
the technical basis and purpose of the proposed Reliability Standard, a demonstration that the
proposed Reliability Standard meets the criteria identified by the Commission in Order No. 672 6
(Exhibit C), and a summary of the standard development history (Exhibit E). The proposed
Reliability Standard was adopted by the NERC Board of Trustees on February 8, 2018.
This Petition is organized as follows: Section I of the Petition presents an executive
summary of the proposed Reliability Standard. Section II of the Petition provides the individuals
to whom notices and communications related to the filing should be provided. Section III
provides background on the regulatory structure governing the Reliability Standards approval
process. This section also provides information on the development of the proposed Reliability
Standards through Project 2016-04 - Modifications to PRC-025-1. Section IV of the Petition
provides a detailed discussion of the proposed Reliability Standard and explains how the
proposed standard enhances reliability and improves flexibility in applying the various options.
Section V of the Petition provides a summary of the proposed implementation plan.
EXECUTIVE SUMMARY
Proposed Reliability Standard PRC-025-2 adds enhancements to the currently-effective
generator loadability standard PRC-025-1, to better address risks of unnecessary generator

5

18 C.F.R. § 39.5(a).
The Commission specified in Order No. 672 certain general factors it would consider when assessing
whether a particular Reliability Standard is just and reasonable. See Rules Concerning Certification of the Electric
Reliability Organization; and Procedures for the Establishment, Approval, and Enforcement of Electric Reliability
Standards, Order No. 672, FERC Stats. & Regs. ¶ 31,204, at P 262, 321-37, order on reh’g, Order No. 672-A,
FERC Stats. & Regs. ¶ 31,212 (2006).
6

2

tripping where the voltage is depressed and the generator is capable of increased Reactive Power
output and voltage support during the disturbance. During the implementation of Reliability
Standard PRC-025-1, NERC and industry identified the need to revise the standard to address
certain applications and to clarify language to advance the reliability goals of the standard. These
revisions are reflected in proposed Reliability Standard PRC-025-2. Specifically, the proposed
Reliability Standard:
1. adds a provision to Attachment 1, Table 1 Relay Loadability Evaluation Criteria
to address dispersed power producing resources that are unable to be set at 130%
of the calculated current due to physical limitations of the protection equipment;
2. adds to the Table 1 relay type description the protective relay 50 Element
associated with instantaneous (i.e., without intentional time delay) tripping of
overcurrent based protection;
3. clarifies, in the Table 1 Application column, that an entity must apply settings to
all the applications described therein;
4. clarifies that an entity, when employing simulation for setting relays associated
with the transmission line interconnecting the generator or plant to the
Transmission system, must simulate the 0.85 per unit depressed voltage at the
remote end (i.e., Transmission system side) of the line;
5. removes the term “Pick Up” from the Attachment 1, Table 1 heading (so that the
new heading reads “Setting Criteria”), to better align the setting to the calculated
or simulated capability of the generator with an associated margin; and
6. clarifies certain terminology and references.
For the reasons explained more fully in this Petition, NERC requests that the Commission
approve proposed Reliability Standard PRC-025-2 and find that the proposed standard is just,
reasonable, not unduly discriminatory or preferential, and in the public interest.

3

NOTICES AND COMMUNICATIONS
Notices and communications with respect to this filing may be addressed to the following: 7
Shamai Elstein*
Senior Counsel
Lauren A. Perotti*
Counsel
North American Electric Reliability Corporation
1325 G Street, N.W., Suite 600
Washington, D.C. 20005
(202) 400-3000
(202) 644-8099– facsimile
shamai.elstein@nerc.net
lauren.perotti@nerc.net

Howard Gugel*
Director of Standards
North American Electric Reliability Corporation
3353 Peachtree Road, N.E.
Suite 600, North Tower
Atlanta, GA 30326
(404) 446-2560
(404) 446-2595 – facsimile
howard.gugel@nerc.net

BACKGROUND
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
(“BPS”), and with the duties of certifying an ERO that would be charged with developing and
enforcing mandatory Reliability Standards, subject to Commission approval. Section 215(b)(1) 9
of the FPA states that all users, owners, and operators of the BPS in the United States will be
subject to Commission-approved Reliability Standards. Section 215(d)(5) 10 of the FPA
authorizes the Commission to order the ERO to submit a new or modified Reliability Standard.
Section 39.5(a) 11 of the Commission’s regulations requires the ERO to file with the Commission
for its approval each new Reliability Standard that the ERO proposes should become mandatory
7

Persons to be included on the Commission’s service list are identified by an asterisk. NERC respectfully
requests a waiver of Rule 203 of the Commission’s regulations, 18 C.F.R. § 385.203 (2017), to allow the inclusion
of more than two persons on the service list in this proceeding.
8
16 U.S.C. § 824o.
9
Id. § 824o(b)(1).
10
Id. § 824o(d)(5).
11
18 C.F.R. § 39.5(a).

4

and enforceable in the United States, and each modification to a Reliability Standard that the
ERO proposes should be made effective.
The Commission is vested with the regulatory responsibility to approve Reliability
Standards that protect the reliability of the BPS and to ensure that Reliability Standards are just,
reasonable, not unduly discriminatory or preferential, and in the public interest. Pursuant to
Section 215(d)(2) of the FPA 12 and Section 39.5(c) 13 of the Commission’s regulations, the
Commission will give due weight to the technical expertise of the ERO with respect to the
content of a Reliability Standard.
B.

NERC Reliability Standards Development Procedure

The proposed Reliability Standard was developed in an open and fair manner and in
accordance with the Commission-approved Reliability Standard development process. 14 NERC
develops Reliability Standards in accordance with Section 300 (Reliability Standards
Development) of its Rules of Procedure and the NERC Standard Processes Manual. 15
In its order certifying NERC as the Commission’s ERO, the Commission found that
NERC’s rules provide for reasonable notice and opportunity for public comment, due process,
openness, and a balance of interests in developing Reliability Standards, 16 and thus satisfy
certain of the criteria for approving Reliability Standards. 17 The development process is open to
any person or entity with a legitimate interest in the reliability of the BPS. NERC considers the

12

16 U.S.C. § 824o(d)(2).
18 C.F.R. § 39.5(c)(1).
14
Order No. 672, Rules Concerning Certification of the Electric Reliability Organization; and Procedures for
the Establishment, Approval, and Enforcement of Electric Reliability Standards, FERC Stats. & Regs. ¶ 31,204,
order on reh’g, Order No. 672-A, FERC Stats. & Regs. ¶ 31,212 (2006).
15
The NERC Rules of Procedure are available at http://www.nerc.com/AboutNERC/Pages/Rules-ofProcedure.aspx. The NERC Standard Processes Manual is available at
http://www.nerc.com/comm/SC/Documents/Appendix_3A_StandardsProcessesManual.pdf.
16
N. Am. Elec. Reliability Corp., 116 FERC ¶ 61,062 at P 250 (2006).
17
Order No. 672 at PP 268, 270.
13

5

comments of all stakeholders. Stakeholders must approve, and the NERC Board of Trustees must
adopt, a Reliability Standard before NERC submits the Reliability Standard to the Commission
for approval.
C.

Project 2016-04 Modifications to PRC-025-1

On July 17, 2014, the Commission issued Order No. 799 approving Reliability Standard
PRC-025-1. 18 Reliability Standard PRC-025-1 was developed in response to certain Commission
directives in Order No. 733 19 to develop a standard governing generator protective relay
loadability. Reliability Standard PRC-025-1 requires applicable Generator Owners, Transmission
Owners, and Distribution Providers to apply an appropriate setting for load-responsive relays
based on calculations or simulations for conditions established in Attachment 1 of the standard.
The Attachment 1 criteria are representative of the short-term conditions during which
generation Facilities have, in the past, disconnected when otherwise capable of providing
Reactive Power. Under the phased implementation plan for PRC-025-1, applicable entities have
between five and seven years to become compliant with the standard, depending on the scope of
work required.
In the course of implementing Reliability Standard PRC-025-1, industry identified issues
for specific Facility applications and load-responsive protective relays. To address these issues,
NERC initiated Project 2016-04 Modifications to PRC-025-1 in September 2016. The standard
authorization request for this project directed the standard drafting team (“SDT”) to consider
revisions to the standard that would:

18

Generator Relay Loadability and Revised Transmission Relay Loadability Reliability Standards, Order No.
799, 148 FERC ¶ 61,042 (2014). In this order, the Commission also approved Reliability Standard PRC-023-3,
which included clarifying changes to PRC-023-2 to establish a bright line between the applicability of loadresponsive protective relays in the transmission and generator relay loadability Reliability Standards.
19
Transmission Relay Loadability Reliability Standard, Order No. 733, 130 FERC ¶ 61,221 (2010) (Order
No. 733); order on reh’g and clarification, Order No. 733-A, 134 FERC ¶ 61,127; clarified, Order No. 733-B, 136
FERC ¶ 61,185 (2011).

6

•

Prevent instances of non-compliance for conditions where the Generator Owner may be
prevented from achieving the margin specified by the standard for dispersed power
producing resources.

•

Prevent a lowering of reliability and potential non-compliance where the Generator
Owner might apply a non-standard relay element application and undermine the goal of
the standard.

•

Prevent a lowering of reliability where the Generator Owner might only apply part of the
Table 1 application(s), thereby misapplying the loadability margins to relays for the
stated application(s).

•

Prevent a lowering of dependability of protective relays directional toward the
Transmission system at generating facilities that are remote to the transmission network.

•

Modify or eliminate the use of the term “pickup setting” and other terms or phrases that
relate to initial measurements and specific detection methods, and instead, use a term or
phrase that clearly aligns with the intent of the standard for relays to “not trip” based on
the criteria in Table 1.

•

Clarify miscellaneous aspects of the standard, Attachment 1, and/or the Application
Guidelines.
The SDT revised the PRC-025 standard to address the issues summarized above and to

clarify language. Following two comment and ballot periods, proposed Reliability Standard
PRC-025-2 was approved by the ballot pool on January 18, 2018. The NERC Board of Trustees
adopted the proposed standard on February 8, 2018.
JUSTIFICATION FOR APPROVAL
As discussed in Exhibit C and below, proposed Reliability Standard PRC-025-2 satisfies
the Commission’s criteria in Order No. 672 and is just, reasonable, not unduly discriminatory or
preferential, and in the public interest. Proposed Reliability Standard PRC-025-2 continues to
consist of a single Requirement, Requirement R1, which requires entities to apply settings that
are in accordance with Attachment 1: Relay Settings on each applicable load-responsive
protective relay while maintaining reliable fault protection. The majority of the revisions in
proposed PRC-025-2 are in Attachment 1. Corresponding revisions have been made to the
Guidelines and Technical Basis material following the standard. A summary of the proposed

7

standard revisions and the justification for each is provided below. The proposed revisions are
shown in the PRC-025-2 redline attached to this Petition as Exhibit A.
A.

Revisions to Address Dispersed Power Producing Resources

Reliability Standard PRC-025-1 Table 1 Option 5 requires setting the overcurrent relay of
a Protection System applied to an asynchronous generating unit or an Element utilized in the
aggregation of dispersed power producing resources to a margin greater than 130% of the
calculated current derived from the maximum aggregate nameplate megavolt-ampere (MVA)
output at rated power factor. In some cases, manufacturer requirements or the physical
limitations of dispersed power producing resources may prevent the entity from being able to
achieve the 130% threshold. For example, the entity may exceed a manufacturer’s warranty or
design criteria when applying 130% margin to the calculated current based on the aggregate
output or individual resource. As an example of a physical limitation, the physical size of the
resource may prevent the entity from being able to install a larger breaker frame in order to meet
the 130% margin. Other limitations include the inability of the resource to produce a level of
current that would be capable of reaching the 130% threshold; many asynchronous resources
(e.g., inverters) are only capable of producing 1.1 to 1.2 per unit (110-120%) of their rated
output.
To ensure that the load-responsive protective relays associated with asynchronous
generation Facilities may be set at a level to prevent unnecessary tripping during a system
disturbance, the proposed Reliability Standard PRC-025-2 Table 1 adds an alternative setting
option, Option 5b. 20 Option 5b is available for inverter based machines that cannot achieve the
130% threshold due to the limitations described above. Protective devices associated with this

20

Current Option 5 remains in Table 1 as Option 5a for entities that have implemented the 130% setting.

8

equipment generally have adjustable trip values that allow the protection setting to be set not to
infringe on the capability of the resource. Under new Option 5b, the overcurrent element shall be
set greater than the maximum capability of the asynchronous resource and applicable equipment.
The lower tolerance of the overcurrent element tripping characteristic shall be set to not infringe
upon the resource capability (including the Mvar output of the resource and any static or
dynamic reactive power control devices). 21 Option 5b refers to a new figure, Figure A, to
demonstrate that the overcurrent element tripping characteristic shall not infringe upon the
asynchronous resource capability.
The proposed standard also includes a new footnote 1 in the Applicability section
concerning asynchronous resources. These resources are generally connected at voltages less
than 1,000 volts. Footnote 1 clarifies that load-responsive protective relays include low-voltage
protection devices that have adjustable settings.
B.

Revisions to Address Non-Standard Relay Element Applications

Proposed Reliability Standard PRC-025-2 improves upon the currently-effective version
of the standard by addressing the inclusion of the IEEE 50 device element 22 and other similar
instantaneous (i.e., without intentional delay) overcurrent elements for the various overcurrent
applications within Table 1. In practice, a 50 element is generally set with a very high pick up
and well above the loadability levels determined by the standard. By including the 50 element in
Table 1, the proposed standard clarifies that the 50 element must also achieve the same or greater
level of loadability as the 51 element (i.e., with intentional delay). The inclusion of the 50

21

See proposed Reliability Standard PRC-025-2 (Exhibit A), Guidelines and Technical Basis at 45.
Device numbers are identified in Institute of Electrical and Electronics Engineers (“IEEE”) Std. C37.22008, IEEE Standard Electrical Power System Device Function Numbers, Acronyms, and Contact Designations.
(2008). A citation to IEEE Standard C37.2-2008 is added to the Associated Documents section to clarify that the
IEEE device numbers within the PRC-025-2 standard refer to typical protective device functions used by entities
applying load-responsive protective relays to Elements on the BPS.
22

9

element avoids the potential for setting the 50 element inconsistent with the objectives of the
standard and unknowingly creating a 51 element 23 by adding a definite time characteristic, which
is applicable to the standard. Including the 50 element avoids the risk where the overcurrent
element could be applied with a lower, less desirable loadability setting according to the
applications in Table 1.
In addition, revisions are made in Attachment 1 to clarify that IEEE device numbering
convention varies by manufacturer. For example, a voltage-restrained (i.e., V-R) relay is variably
referred to by IEEE function numbers 51V, 51R, 51VR, 51V/R, 51V-R, or other terms as
discussed in the Guidelines and Technical Basis section under the heading Phase Time
Overcurrent Relay – Voltage-Restrained (e.g., 51V-R). Likewise, manufacturers of low-voltage
equipment generally use protective device trip unit designations for long-time delay, short-time
delay, and instantaneous and are referred to as long (L), short (S), and instantaneous (I) as
discussed in Attachment 1 under the narrative heading Table 1. Although low-voltage
designations are not specifically identified in Table 1, their relationship to the IEEE device
numbers are widely understood by industry protection engineers.
These revisions improve the PRC-025 standard by drawing attention to the potential
loadability issues when using the 50 element and by increasing awareness that not all protective
relays are designated by an IEEE device number.
C.

Revisions to Clarify Application Column of Table 1

Proposed Reliability Standard PRC-025-2 reflects several revisions to clarify the
Application column of Table 1. In several places in the Application column of Reliability
Standard PRC-025-1 Table 1, it is not clear whether applicable protective relays associated with

23

Any 50 element being applied with a definite time characteristic is, by the IEEE definition, a 51 element
and applicable to the standard.

10

all listed Elements are to be set using the setting criteria of Table 1 or just one of the multiple
listed Elements. For example, in Options 4, 5, and 6, the Application column provides:
“Asynchronous generating unit(s) (including inverter-based installations), or Elements utilized in
the aggregation of dispersed power producing resources” (emphasis added). Entities could
interpret the use of the “or” conjunction to require setting of only one particular application and
not the other. To clarify that applicable protective relays associated with all listed Elements are
to be set using the setting criteria in Table 1, revisions are proposed in the Application column of
PRC-025-2 Table 1 for Options 1 through 6. The proposed language advances the goal of the
Reliability Standard to ensure that loadability margins are applied to relays on all specified
Elements from the generation resource to the Transmission system.
Other clarifications were made to Options 7 through 12 and 14 through 19 of Table 1 to
remove the described location of the relay from the “Relay Type” column to the “Application”
column.
D.

Revisions to Address Dependability of Protective Relays that Interconnect
Generating Facilities to the Transmission System

Proposed Reliability Standard PRC-025-2 contains revisions to Table 1 Options 14b, 15b,
and 16b to address cases where the interconnecting Transmission line impedance impacts the
maximum Reactive Power capability of the generator or plant. Where a generating Facility is
generally small (i.e., electrically weak) and remote (i.e., as few as 20 miles) to the Transmission
network, the maximum Reactive Power output capability can be significantly lower than the
capability determined by the specific Table 1 Options. For these Facilities, setting loadresponsive protective relays using the maximum resource capability without considering the
effects of line impedance could result in an overly conservative loadability setting. An overly
conservative setting could reduce relay dependability for clearing faults, create substantive
11

difficulty in coordinating backup protection schemes, or result in the application of more
complex and costly protective schemes (e.g., transfer-trip).
These revisions move the point of the system disturbance (i.e., 0.85 per unit nominal
voltage) from the terminals of the generator step-up transformer to the remote end of the line to
account for the effects of line impedance. This revision enhances reliability by improving
dependability of load-responsive protective relays for clearing faults, reducing difficulty in
coordinating backup protection schemes, and potentially eliminating the need for more complex
and costly protective schemes.
E.

Revisions to Address Use of Term “Pickup Setting”

Reliability Standard PRC-025-1 uses the term “pickup setting”; this term relates to initial
measurements and specific detection methods (see, e.g., Table 1 “Pickup Setting Criteria”). The
intent of the standard, however, is for relays to “not trip” based on the capability of the generator
or plant, using the criteria in Table 1. To address this issue and avoid the assumption that an
initial specific measurement is mandatory, the term “pickup” is eliminated from the fifth column
of proposed Reliability Standard PRC-025-2 Table 1 so that it reads “Setting Criteria.”
Confirming changes are made in the Attachment 1 text preceding Table 1.
F.

Miscellaneous Revisions to Attachment 1: Relay Settings

Revisions are proposed in PRC-025-2 Attachment 1 under the “Generators” heading to
clarify that the phrase regarding unit capability “reported to the Transmission Planner” is a
minimum criterion and that a greater unit capability is acceptable. Additionally, low voltage
protection devices that do not have adjustable settings are now specifically listed under the list of
Exclusions in Attachment 1. This change is consistent with the addition of the new footnote 1 in
the Applicability section of the standard described above.

12

G.

Revisions to PRC-025 Guidelines and Technical Basis

In accordance with the standard authorization request for this project, NERC has revised
the Guidelines and Technical Basis section for proposed Reliability Standard PRC-025-2 to add
supporting information regarding the above-described standard changes as well as provide
clarification in several areas. For example, revisions have been made to clarify the various
Figures, which illustrate the standard’s applicability to a given configuration. As the Guidelines
and Technical Basis section is not enforceable, NERC does not seek approval for these revisions
but describes them for informational purposes only.
H.

Enforceability of the Proposed Reliability Standard

The proposed Reliability Standard contains a VRF of High and VSL of Severe for the
single standard Requirement, Requirement R1. The VRF and VSL remain unchanged from
currently-enforceable Reliability Standard PRC-025-1. The VSL provides guidance on the way
that NERC will enforce the Requirements of the proposed Reliability Standard. The VRF is one
of several elements used to determine an appropriate sanction when the associated Requirement
is violated. The VRF assesses the impact to reliability of violating a specific Requirement.
In addition, the proposed Reliability Standard also includes a Measure that supports
Requirement R1 by clearly identifying what is required and how the Requirement will be
enforced. This Measure, which is unchanged from currently-enforceable Reliability Standard
PRC-025-1, helps ensure that the Requirement will be enforced in a clear, consistent, and nonpreferential manner and without prejudice to any party.
EFFECTIVE DATE
NERC respectfully requests that the Commission approve the proposed implementation
plan attached to this Petition as Exhibit B. Under the proposed implementation plan, Reliability
Standard PRC-025-2 would become effective on the first day of the first calendar quarter after
13

regulatory approval. Reliability Standard PRC-025-1 would be retired immediately prior to the
effective date of PRC-025-2.
Under the PRC-025-1 implementation plan, entities have either 60 or 84 months to come
into compliance with the standard, as follows:
•

60 months, where the entity applies settings to its existing load-responsive relays
that are capable of meeting the standard while maintaining reliable fault
protection, or by October 1, 2019 for U.S.-based entities; or

•

84 months, where the entity needs to replace or remove its existing loadresponsive protective relays, or by October 1, 2021.

The proposed PRC-025-2 implementation plan recognizes that entities are in the process
of implementing the standard to meet these dates, but that certain revisions in PRC-025-2 may
give reason for entities to re-evaluate their settings for load-responsive protective relays or
require further time for implementation. The proposed PRC-025-2 implementation plan provides
a new phased compliance schedule that is intended to supersede the phased compliance schedule
provided in the currently-effective PRC-025-1 implementation plan. For existing Options,
entities would have at least as much time to come into compliance with the proposed standard as
they would have under the PRC-025-1 implementation plan. New phased compliance dates are
provided for new and revised Table 1 Relay Loadability Evaluation Criteria Options, including:
•

New Option 5b: 24 or 48 months, depending on whether replacement or removal
is necessary;

•

For the 50 element only in Options 2a, 2b, 2c, 5a, 5b, 8a, 8b, 8c, 11, 13a, and 13b:
60 or 84 months, depending on whether replacement or removal is necessary;

•

Revised Options 14b, 15b, 16b: 24 or 48 months, depending on whether
replacement or removal is necessary.

For load-responsive relays that later become applicable to the proposed standard, entities
would continue to have 60 or 84 months to come into compliance, depending on whether
replacement or removal is necessary.
14

The proposed implementation plan provides additional timing for new Option 5b due to
the number of dispersed power generating resources that may be have been unable to apply the
existing 130% threshold; however, the burden to adjust the settings to ensure the capability of the
resource does not infringe on the protection setting is expected to be minimal.
The proposed implementation plan also provides a full 60 and 84 month implementation
timeline to address the newly-added 50 element in certain Options. This timeline accounts for
engineering review, potential equipment procurement, and outage coordination to commission
the equipment and apply the appropriate settings.
Additionally, the proposed implementation plan allows entities sufficient time to address
newly-revised Options addressing Transmission lines interconnecting the generating unit or plant
to the Transmission system. The proposed timeframe allows entities to re-evaluate their settings
to account for line impedance effects and to make appropriate modifications to the settings.

15

CONCLUSION
For the reasons set forth above, NERC respectfully requests that the Commission
approve:
•

proposed Reliability Standard PRC-025-2 and associated elements included in
Exhibit A;

•

the implementation plan included in Exhibit B; and

•

the retirement of currently-effective Reliability Standard PRC-025-1.

Respectfully submitted,
/s/ Lauren A. Perotti
Shamai Elstein
Senior Counsel
Lauren A. Perotti
Counsel
North American Electric Reliability Corporation
1325 G Street, N.W., Suite 600
Washington, D.C. 20005
(202) 400-3000
(202) 644-8099– facsimile
shamai.elstein@nerc.net
lauren.perotti@nerc.net
Counsel for the North American Electric
Reliability Corporation
March 16, 2018

16