Reliability Standards-PRC-005-4

Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

A. Introduction
1. Title:

Protection System, Automatic Reclosing, and Sudden Pressure Relaying
Maintenance
2. Number: PRC-005-4
3. Purpose: To document and implement programs for the maintenance of all
Protection Systems, Automatic Reclosing, and Sudden Pressure Relaying
affecting the reliability of the Bulk Electric System (BES) so that they are kept
in working order.
3.1. Functional Entities:
3.1.1 Transmission Owner
3.1.2 Generator Owner
3.1.3 Distribution Provider
3.2. Facilities:
3.2.1 Protection Systems and Sudden Pressure Relaying that are installed for
the purpose of detecting Faults on BES Elements (lines, buses,
transformers, etc.)
3.2.2 Protection Systems used for underfrequency load-shedding systems
installed per ERO underfrequency load-shedding requirements.
3.2.3 Protection Systems used for undervoltage load-shedding systems
installed to prevent system voltage collapse or voltage instability for BES
reliability.
3.2.4 Protection Systems installed as a Remedial Action Scheme (RAS) for BES
reliability.
3.2.5 Protection Systems and Sudden Pressure Relaying for generator Facilities
that are part of the BES, including:
3.2.5.1 Protection Systems that act to trip the generator either directly
or via lockout or auxiliary tripping relays.
3.2.5.2 Protection Systems and Sudden Pressure Relaying for
generator step-up transformers for generators that are part of
the BES.
3.2.5.3 Protection Systems and Sudden Pressure Relaying for
transformers connecting aggregated generation, where the
aggregated generation is part of the BES (e.g., transformers
connecting facilities such as wind-farms to the BES).
3.2.5.4 Protection Systems and Sudden Pressure Relaying for station
service or excitation transformers connected to the generator
bus of generators which are part of the BES, that act to trip the

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

generator either directly or via lockout or tripping auxiliary
relays.
3.2.6 Automatic Reclosing,1 including:
3.2.6.1 Automatic Reclosing applied on the terminals of Elements
connected to the BES bus located at generating plant
substations where the total installed gross generating plant
capacity is greater than the gross capacity of the largest BES
generating unit within the Balancing Authority Area or, if a
member of a Reserve Sharing Group, the largest generating
unit within the Reserve Sharing Group. 2
3.2.6.2 Automatic Reclosing applied on the terminals of all BES
Elements at substations one bus away from generating plants
specified in Section 4.2.6.1 when the substation is less than 10
circuit-miles from the generating plant substation.
4.2.6.3. Automatic Reclosing applied as an integral part of an RAS
specified in Section 4.2.4.
4. Effective Date: See Implementation Plan
5. Definitions Used in this Standard:
Automatic Reclosing – Includes the following Components:


Reclosing relay



Control circuitry associated with the reclosing relay.

Sudden Pressure Relaying – A system that trips an interrupting device(s) to isolate the
equipment it is monitoring and includes the following Components:


Fault pressure relay – a mechanical relay or device that detects rapid changes in
gas pressure, oil pressure, or oil flow that are indicative of Faults within liquidfilled, wire-wound equipment



Control circuitry associated with a fault pressure relay

1

Automatic Reclosing addressed in Section 4.2.6.1 and 4.2.6.2 may be excluded if the equipment owner can demonstrate that a
close-in three-phase fault present for twice the normal clearing time (capturing a minimum trip-close-trip time delay) does not
result in a total loss of gross generation in the Interconnection exceeding the gross capacity of the largest relevant BES
generating unit where the Automatic Reclosing is applied.
2 The largest BES generating unit within the Balancing Authority Area or the largest generating unit within the Reserve Sharing
Group, as applicable, is subject to change. As a result of such a change, the Automatic Reclosing Components subject to the
standard could change effective on the date of such change.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Unresolved Maintenance Issue – A deficiency identified during a maintenance activity
that causes the Component to not meet the intended performance, cannot be corrected
during the maintenance interval, and requires follow-up corrective action.
Segment – Components of a consistent design standard, or a particular model or type
from a single manufacturer that typically share other common elements. Consistent
performance is expected across the entire population of a Segment. A Segment must
contain at least sixty (60) individual Components.
Component Type –
 Any one of the five specific elements of a Protection System.
 Any one of the two specific elements of Automatic Reclosing.
 Any one of the two specific elements of Sudden Pressure Relaying.
Component – Any individual discrete piece of equipment included in a Protection
System, Automatic Reclosing, or Sudden Pressure Relaying.
Countable Event – A failure of a Component requiring repair or replacement, any
condition discovered during the maintenance activities in Tables 1-1 through 1-5, Table
3, Tables 4-1 through 4-2, and Table 5, which requires corrective action or a Protection
System Misoperation attributed to hardware failure or calibration failure.
Misoperations due to product design errors, software errors, relay settings different
from specified settings, Protection System Component, Automatic Reclosing, or Sudden
Pressure Relaying configuration or application errors are not included in Countable
Events.
B. Requirements and Measures
R1.

Each Transmission Owner, Generator Owner, and Distribution Provider shall establish
a Protection System Maintenance Program (PSMP) for its Protection Systems,
Automatic Reclosing, and Sudden Pressure Relaying identified in Section 4.2, Facilities.
[Violation Risk Factor: Medium] [Time Horizon: Operations Planning]
The PSMP shall:
1.1. Identify which maintenance method (time-based, performance-based per PRC005 Attachment A, or a combination) is used to address each Protection System,
Automatic Reclosing, and Sudden Pressure Relaying Component Type. All
batteries associated with the station dc supply Component Type of a Protection
System shall be included in a time-based program as described in Table 1-4 and
Table 3.
1.2. Include the applicable monitored Component attributes applied to each
Protection System, Automatic Reclosing, and Sudden Pressure Relaying
Component Type consistent with the maintenance intervals specified in Tables 11 through 1-5, Table 2, Table 3, Table 4-1 through 4-2, and Table 5 where
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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

monitoring is used to extend the maintenance intervals beyond those specified
for unmonitored Protection System, Automatic Reclosing, and Sudden Pressure
Relaying Components.
M1. Each Transmission Owner, Generator Owner and Distribution Provider shall have a
documented Protection System Maintenance Program in accordance with
Requirement R1.
For each Protection System, Automatic Reclosing, and Sudden Pressure Relaying
Component Type, the documentation shall include the type of maintenance method
applied (time-based, performance-based, or a combination of these maintenance
methods), and shall include all batteries associated with the station dc supply
Component Types in a time-based program as described in Table 1-4 and Table 3.
(Part 1.1)
For Component Types that use monitoring to extend the maintenance intervals, the
responsible entity(s) shall have evidence for each Protection System, Automatic
Reclosing, and Sudden Pressure Relaying Component Type (such as manufacturer’s
specifications or engineering drawings) of the appropriate monitored Component
attributes as specified in Tables 1-1 through 1-5, Table 2, Table 3, Table 4-1 through 42, and Table 5. (Part 1.2)
R2.

Each Transmission Owner, Generator Owner, and Distribution Provider that uses
performance-based maintenance intervals in its PSMP shall follow the procedure
established in PRC-005 Attachment A to establish and maintain its performance-based
intervals. [Violation Risk Factor: Medium] [Time Horizon: Operations Planning]

M2. Each Transmission Owner, Generator Owner, and Distribution Provider that uses
performance-based maintenance intervals shall have evidence that its current
performance-based maintenance program(s) is in accordance with Requirement R2,
which may include, but is not limited to, Component lists, dated maintenance records,
and dated analysis records and results.
R3.

Each Transmission Owner, Generator Owner, and Distribution Provider that utilizes
time-based maintenance program(s) shall maintain its Protection System, Automatic
Reclosing, and Sudden Pressure Relaying Components that are included within the
time-based maintenance program in accordance with the minimum maintenance
activities and maximum maintenance intervals prescribed within Tables 1-1 through
1-5, Table 2, Table 3, Table 4-1 through 4-2, and Table 5. [Violation Risk Factor: High]
[Time Horizon: Operations Planning]

M3. Each Transmission Owner, Generator Owner, and Distribution Provider that utilizes
time-based maintenance program(s) shall have evidence that it has maintained its
Protection System, Automatic Reclosing, and Sudden Pressure Relaying Components
included within its time-based program in accordance with Requirement R3. The
evidence may include, but is not limited to, dated maintenance records, dated
maintenance summaries, dated check-off lists, dated inspection records, or dated
work orders.
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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

R4.

Each Transmission Owner, Generator Owner, and Distribution Provider that utilizes
performance-based maintenance program(s) in accordance with Requirement R2 shall
implement and follow its PSMP for its Protection System, Automatic Reclosing, and
Sudden Pressure Relaying Components that are included within the performancebased program(s). [Violation Risk Factor: High] [Time Horizon: Operations Planning]

M4. Each Transmission Owner, Generator Owner, and Distribution Provider that utilizes
performance-based maintenance intervals in accordance with Requirement R2 shall
have evidence that it has implemented the Protection System Maintenance Program
for the Protection System, Automatic Reclosing, and Sudden Pressure Relaying
Components included in its performance-based program in accordance with
Requirement R4. The evidence may include, but is not limited to, dated maintenance
records, dated maintenance summaries, dated check-off lists, dated inspection
records, or dated work orders.
R5. Each Transmission Owner, Generator Owner, and Distribution Provider shall
demonstrate efforts to correct identified Unresolved Maintenance Issues. [Violation
Risk Factor: Medium] [Time Horizon: Operations Planning]
M5. Each Transmission Owner, Generator Owner, and Distribution Provider shall have
evidence that it has undertaken efforts to correct identified Unresolved Maintenance
Issues in accordance with Requirement R5. The evidence may include, but is not
limited to, work orders, replacement Component orders, invoices, project schedules
with completed milestones, return material authorizations (RMAs) or purchase
orders.
C. Compliance
1.

Compliance Monitoring Process
1.1. Compliance Enforcement Authority
As defined in the NERC Rules of Procedure, “Compliance Enforcement
Authority” means NERC or the Regional Entity in their respective roles of
monitoring and enforcing compliance with the NERC Reliability Standards.
1.2. 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.
The Transmission Owner, Generator Owner, and Distribution Provider shall
each keep data or evidence to show compliance as identified below unless

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

directed by its Compliance Enforcement Authority to retain specific evidence for
a longer period of time as part of an investigation.
For Requirement R1, the Transmission Owner, Generator Owner, and
Distribution Provider shall each keep its current dated Protection System
Maintenance Program, as well as any superseded versions since the preceding
compliance audit, including the documentation that specifies the type of
maintenance program applied for each Protection System, Automatic Reclosing,
or Sudden Pressure Relaying Component Type.
For Requirement R2, Requirement R3, and Requirement R4, in cases where the
interval of the maintenance activity is longer than the audit cycle, the
Transmission Owner, Generator Owner, and Distribution Provider shall each
keep documentation of the most recent performance of that maintenance
activity for the Protection System, Automatic Reclosing, or Sudden Pressure
Relaying Component. In cases where the interval of the maintenance activity is
shorter than the audit cycle, documentation of all performances (in accordance
with the tables) of that maintenance activity for the Protection System,
Automatic Reclosing, or Sudden Pressure Relaying Component since the
previous scheduled audit date shall be retained.
For Requirement R5 the Transmission Owner, Generator Owner, and
Distribution Provider shall each keep documentation of Unresolved
Maintenance Issues identified by the entity since the last audit, including all
that were resolved since the last audit.
The Compliance Enforcement Authority shall keep the last audit records and all
requested and submitted subsequent audit records.
1.3. Compliance Monitoring and Assessment Processes:
Compliance Audits
Self-Certifications
Spot Checking
Compliance Violation Investigations
Self-Reporting
Complaints
1.4. Additional Compliance Information
None

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table of Compliance Elements
Requirement
Number
R1

Lower VSL

Moderate VSL

High VSL

Severe VSL

The entity’s PSMP failed to specify
whether one Component Type is
being addressed by time-based or
performance-based maintenance, or
a combination of both (Part 1.1).

The entity’s PSMP failed to specify
whether two Component Types are
being addressed by time-based or
performance-based maintenance,
or a combination of both (Part 1.1).

The entity’s PSMP failed to specify
whether three Component Types
are being addressed by time-based
or performance-based maintenance,
or a combination of both. (Part 1.1).

The entity failed to establish a
PSMP.

OR
The entity’s PSMP failed to include
the applicable monitoring attributes
applied to each Component Type
consistent with the maintenance
intervals specified in Tables 1-1
through 1-5, Table 2, Table 3, Tables
4-1 through 4-2, and Table 5 where
monitoring is used to extend the
maintenance intervals beyond those
specified for unmonitored
Components (Part 1.2).
R2

The entity uses performance-based
maintenance intervals in its PSMP
but failed to reduce Countable
Events to no more than 4% within
three years.

NA

The entity uses performance-based
maintenance intervals in its PSMP
but failed to reduce Countable
Events to no more than 4% within
four years.

OR
The entity’s PSMP failed to specify
whether four or more Component
Types are being addressed by timebased or performance-based
maintenance, or a combination of
both (Part 1.1).
OR
The entity’s PSMP failed to include
applicable station batteries in a
time-based program (Part 1.1).

The entity uses performance-based
maintenance intervals in its PSMP
but:
1) Failed to establish the
technical justification
described within Requirement
R2 for the initial use of the
performance-based PSMP
OR
2) Failed to reduce Countable
Events to no more than 4%
within five years
OR

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Requirement
Number

Lower VSL

Moderate VSL

High VSL

Severe VSL
3) Maintained a Segment with
less than 60 Components
OR
4) Failed to:
• Annually update the list of
Components,
OR
• Annually perform
maintenance on the
greater of 5% of the
Segment population or 3
Components,
OR
• Annually analyze the
program activities and
results for each Segment.

R3

For Components included within a
time-based maintenance program,
the entity failed to maintain 5% or
less of the total Components
included within a specific
Component Type in accordance with
the minimum maintenance activities
and maximum maintenance intervals
prescribed within Tables 1-1 through
1-5, Table 2, Table 3, Tables 4-1
through 4-2, and Table 5.

For Components included within a
time-based maintenance program,
the entity failed to maintain more
than 5% but 10% or less of the total
Components included within a
specific Component Type in
accordance with the minimum
maintenance activities and
maximum maintenance intervals
prescribed within Tables 1-1
through 1-5, Table 2, Table 3,
Tables 4-1 through 4-2, and Table 5.

For Components included within a
time-based maintenance program,
the entity failed to maintain more
than 10% but 15% or less of the
total Components included within a
specific Component Type in
accordance with the minimum
maintenance activities and
maximum maintenance intervals
prescribed within Tables 1-1
through 1-5, Table 2, Table 3, Tables
4-1 through 4-2, and Table 5.

For Components included within a
time-based maintenance program,
the entity failed to maintain more
than 15% of the total Components
included within a specific
Component Type in accordance
with the minimum maintenance
activities and maximum
maintenance intervals prescribed
within Tables 1-1 through 1-5,
Table 2, Table 3, Tables 4-1
through 4-2, and Table 5.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Requirement
Number

Lower VSL

Moderate VSL

High VSL

Severe VSL

R4

For Components included within a
performance-based maintenance
program, the entity failed to
maintain 5% or less of the annual
scheduled maintenance for a specific
Component Type in accordance with
their performance-based PSMP.

For Components included within a
performance-based maintenance
program, the entity failed to
maintain more than 5% but 10% or
less of the annual scheduled
maintenance for a specific
Component Type in accordance
with their performance-based
PSMP.

For Components included within a
performance-based maintenance
program, the entity failed to
maintain more than 10% but 15% or
less of the annual scheduled
maintenance for a specific
Component Type in accordance with
their performance-based PSMP.

For Components included within a
performance-based maintenance
program, the entity failed to
maintain more than 15% of the
annual scheduled maintenance for
a specific Component Type in
accordance with their
performance-based PSMP.

R5

The entity failed to undertake efforts
to correct 5 or fewer identified
Unresolved Maintenance Issues.

The entity failed to undertake
efforts to correct greater than 5 but
less than or equal to 10 identified
Unresolved Maintenance Issues.

The entity failed to undertake
efforts to correct greater than 10
but less than or equal to 15
identified Unresolved Maintenance
Issues.

The entity failed to undertake
efforts to correct greater than 15
identified Unresolved Maintenance
Issues.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

D. Regional Variances
None.
E. Interpretations
None.
Supplemental Reference Documents
The following documents present a detailed discussion about determination of
maintenance intervals and other useful information regarding establishment of a
maintenance program.
1. Supplementary Reference and FAQ - PRC-005-4 Protection System Maintenance,
Protection System Maintenance and Testing Standard Drafting Team (April 2014)
2. Considerations for Maintenance and Testing of Auto-reclosing Schemes, NERC System
Analysis and Modeling Subcommittee, and NERC System Protection and Control
Subcommittee (November 2012)
3. Sudden Pressure Relays and Other Devices that Respond to Non-Electrical Quantities –
SPCS Input for Standard Development in Response to FERC Order No. 758, NERC System
Protection and Control Subcommittee (December 2013)
Version History
Version

Date

Action

Change Tracking

0

April 1, 2005

Effective Date

New

1

December 1,
2005

1. Changed incorrect use of
certain hyphens (-) to “en
dash” (–) and “em dash (—).”

01/20/05

2. Added “periods” to items
where appropriate.
3. Changed “Timeframe” to
“Time Frame” in item D, 1.2.
1a

February 17,
2011

Added Appendix 1 - Interpretation
regarding applicability of standard
to protection of radially
connected transformers

1a

February 17,
2011

Adopted by Board of Trustees

1a

September 26,
2011

FERC Order issued approving
interpretation of R1 and R2
(FERC’s Order is effective as of
September 26, 2011)

Project 2009-17 interpretation

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

1b

February 3,
2012

FERC Order issued approving
interpretation of R1, R1.1, and
R1.2 (FERC’s Order dated March
14, 2012). Updated version from
1a to 1b.

Project 2009-10 Interpretation

1.1b

April 23, 2012

Updated standard version to 1.1b
to reflect FERC approval of PRC005-1b.

Revision under Project 201007

1.1b

May 9, 2012

PRC-005-1.1b was adopted by the
Board of Trustees as part of
Project 2010-07 (Generator
Requirements at the Transmission
Interface).

2

November 7,
2012

Adopted by Board of Trustees

2

October 17,
2013

Errata Change: The Standards
Committee
approved an errata change to the
implementation plan for PRC-0052 to add
the phrase “or as otherwise made
effective
pursuant to the laws applicable to
such ERO
governmental authorities;” to the
second
sentence under the “Retirement
of Existing

2(i)

November 13,
2014

Adopted by the NERC Board of
Trustees

2(ii)

November 13,
2014

Adopted by the NERC Board of
Trustees

Project 2007-17 - Complete
revision, absorbing
maintenance requirements
from PRC-005-1.1b, PRC-0080, PRC-011-0, PRC-017-0

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

3

November 7,
2013

Adopted by the NERC Board of
Trustees

3

February 12,
2014

Approved by the Standards
Committee

3(i)

November 13,
2014

Adopted by the NERC Board of
Trustees

3(ii)

November 13,
2014

Adopted by the NERC Board of
Trustees

4

November 13,
2014

Adopted by the NERC Board of
Trustees

Revised to address the FERC
directive in Order No.758 to
include Automatic Reclosing in
maintenance programs.

Errata changes to correct
capitalization of defined terms
(no change to numbering of
standard as a result)

Project 2007-17.3 – Revised to
address the FERC directive in
Order No. 758 to include
sudden pressure relays in
maintenance programs.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-1
Component Type - Protective Relay
Excluding distributed UFLS and distributed UVLS (see Table 3)
Component Attributes

Maximum
Maintenance
Interval3

Maintenance Activities
For all unmonitored relays:
 Verify that settings are as specified
For non-microprocessor relays:

Any unmonitored protective relay not having all the monitoring attributes
of a category below.

6 Calendar
Years

 Test and, if necessary calibrate
For microprocessor relays:
 Verify operation of the relay inputs and outputs that are
essential to proper functioning of the Protection System.
 Verify acceptable measurement of power system input values.

Monitored microprocessor protective relay with the following:

Verify:

 Internal self-diagnosis and alarming (see Table 2).
 Voltage and/or current waveform sampling three or more times per
power cycle, and conversion of samples to numeric values for
measurement calculations by microprocessor electronics.
 Alarming for power supply failure (see Table 2).

12 Calendar
Years

 Settings are as specified.
 Operation of the relay inputs and outputs that are essential to
proper functioning of the Protection System.
 Acceptable measurement of power system input values.

3

For the tables in this standard, a calendar year starts on the first day of a new year (January 1) after a maintenance activity has been completed.
For the tables in this standard, a calendar month starts on the first day of the first month after a maintenance activity has been completed.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-1
Component Type - Protective Relay
Excluding distributed UFLS and distributed UVLS (see Table 3)
Component Attributes

Maximum
Maintenance
Interval3

Maintenance Activities

Monitored microprocessor protective relay with preceding row
attributes and the following:
 Ac measurements are continuously verified by comparison to an
independent ac measurement source, with alarming for excessive
error (See Table 2).
 Some or all binary or status inputs and control outputs are monitored
by a process that continuously demonstrates ability to perform as
designed, with alarming for failure (See Table 2).

12 Calendar
Years

Verify only the unmonitored relay inputs and outputs that are
essential to proper functioning of the Protection System.

 Alarming for change of settings (See Table 2).

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-2
Component Type - Communications Systems
Excluding distributed UFLS and distributed UVLS (see Table 3)
Component Attributes

Maximum
Maintenance
Interval
4 Calendar
Months

Any unmonitored communications system necessary for correct
operation of protective functions, and not having all the monitoring
attributes of a category below.
6 Calendar Years

Maintenance Activities

Verify that the communications system is functional.

Verify that the communications system meets performance criteria
pertinent to the communications technology applied (e.g. signal
level, reflected power, or data error rate).
Verify operation of communications system inputs and outputs that
are essential to proper functioning of the Protection System.

Any communications system with continuous monitoring or periodic
automated testing for the presence of the channel function, and
alarming for loss of function (See Table 2).

12 Calendar
Years

Verify that the communications system meets performance criteria
pertinent to the communications technology applied (e.g. signal
level, reflected power, or data error rate).
Verify operation of communications system inputs and outputs that
are essential to proper functioning of the Protection System.

Any communications system with all of the following:
 Continuous monitoring or periodic automated testing for the
performance of the channel using criteria pertinent to the
communications technology applied (e.g. signal level, reflected
power, or data error rate, and alarming for excessive performance
degradation). (See Table 2)

12 Calendar
Years

Verify only the unmonitored communications system inputs and
outputs that are essential to proper functioning of the Protection
System

 Some or all binary or status inputs and control outputs are
monitored by a process that continuously demonstrates ability to
perform as designed, with alarming for failure (See Table 2).

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-3
Component Type - Voltage and Current Sensing Devices Providing Inputs to Protective Relays
Excluding distributed UFLS and distributed UVLS (see Table 3)
Component Attributes

Any voltage and current sensing devices not having monitoring
attributes of the category below.

Voltage and Current Sensing devices connected to microprocessor
relays with AC measurements are continuously verified by comparison
of sensing input value, as measured by the microprocessor relay, to an
independent ac measurement source, with alarming for unacceptable
error or failure (see Table 2).

Maximum
Maintenance
Interval

12 Calendar Years

No periodic
maintenance
specified

Maintenance Activities

Verify that current and voltage signal values are provided to
the protective relays.

None.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(a)
Component Type – Protection System Station dc Supply Using Vented Lead-Acid (VLA) Batteries
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS systems, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).
Component Attributes

Maximum Maintenance
Interval

Maintenance Activities
Verify:
 Station dc supply voltage

4 Calendar Months

Inspect:
 Electrolyte level
 For unintentional grounds
Verify:

Protection System Station dc supply using Vented
Lead-Acid (VLA) batteries not having monitoring
attributes of Table 1-4(f).

 Float voltage of battery charger
 Battery continuity
 Battery terminal connection resistance
18 Calendar Months

 Battery intercell or unit-to-unit connection resistance
Inspect:
 Cell condition of all individual battery cells where cells are visible – or
measure battery cell/unit internal ohmic values where the cells are
not visible
 Physical condition of battery rack

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(a)
Component Type – Protection System Station dc Supply Using Vented Lead-Acid (VLA) Batteries
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS systems, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).
Component Attributes

Maximum Maintenance
Interval

18 Calendar Months
-or6 Calendar Years

Maintenance Activities
Verify that the station battery can perform as manufactured by
evaluating cell/unit measurements indicative of battery performance
(e.g. internal ohmic values or float current) against the station battery
baseline.
-orVerify that the station battery can perform as manufactured by
conducting a performance or modified performance capacity test of
the entire battery bank.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(b)
Component Type – Protection System Station dc Supply Using Valve-Regulated Lead-Acid (VRLA) Batteries
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS systems, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Verify:
4 Calendar Months

 Station dc supply voltage
Inspect:
 For unintentional grounds
Inspect:

6 Calendar Months
Protection System Station dc supply with Valve Regulated
Lead-Acid (VRLA) batteries not having monitoring attributes of
Table 1-4(f).

 Condition of all individual units by measuring battery cell/unit
internal ohmic values.
Verify:
 Float voltage of battery charger

18 Calendar
Months

 Battery continuity
 Battery terminal connection resistance
 Battery intercell or unit-to-unit connection resistance
Inspect:
 Physical condition of battery rack

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(b)
Component Type – Protection System Station dc Supply Using Valve-Regulated Lead-Acid (VRLA) Batteries
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS systems, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).
Component Attributes

Maximum
Maintenance
Interval

6 Calendar Months
-or3 Calendar Years

Maintenance Activities

Verify that the station battery can perform as manufactured by
evaluating cell/unit measurements indicative of battery performance
(e.g. internal ohmic values or float current) against the station battery
baseline.
-orVerify that the station battery can perform as manufactured by
conducting a performance or modified performance capacity test of
the entire battery bank.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(c)
Component Type – Protection System Station dc Supply Using Nickel-Cadmium (NiCad) Batteries
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS system, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Verify:
 Station dc supply voltage
4 Calendar Months

Inspect:
 Electrolyte level
 For unintentional grounds
Verify:

Protection System Station dc supply Nickel-Cadmium (NiCad)
batteries not having monitoring attributes of Table 1-4(f).

 Float voltage of battery charger
 Battery continuity
18 Calendar
Months

 Battery terminal connection resistance
 Battery intercell or unit-to-unit connection resistance
Inspect:
 Cell condition of all individual battery cells.
 Physical condition of battery rack

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(c)
Component Type – Protection System Station dc Supply Using Nickel-Cadmium (NiCad) Batteries
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS system, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

6 Calendar Years

Verify that the station battery can perform as manufactured by
conducting a performance or modified performance capacity test of
the entire battery bank.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(d)
Component Type – Protection System Station dc Supply Using Non Battery Based Energy Storage
Excluding distributed UFLS and distributed UVLS (see Table 3)

Protection System Station dc supply used only for non-BES interrupting devices for RAS, non-distributed UFLS system, or non-distributed UVLS systems is
excluded (see Table 1-4(e)).

Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Verify:
4 Calendar Months

 Station dc supply voltage
Inspect:
 For unintentional grounds

Any Protection System station dc supply not using a battery
and not having monitoring attributes of Table 1-4(f).

18 Calendar
Months

6 Calendar Years

Inspect:
Condition of non-battery based dc supply
Verify that the dc supply can perform as manufactured when ac power
is not present.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(e)
Component Type – Protection System Station dc Supply for non-BES Interrupting Devices for RAS, non-distributed UFLS, and non-distributed UVLS systems

Component Attributes

Any Protection System dc supply used for tripping only nonBES interrupting devices as part of a RAS, non-distributed
UFLS, or non-distributed UVLS system and not having
monitoring attributes of Table 1-4(f).

Maximum
Maintenance
Interval
When control
circuits are verified
(See Table 1-5)

Maintenance Activities

Verify Station dc supply voltage.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-4(f)
Exclusions for Protection System Station dc Supply Monitoring Devices and Systems
Component Attributes

Maximum Maintenance
Interval

Maintenance Activities

Any station dc supply with high and low voltage monitoring
and alarming of the battery charger voltage to detect charger
overvoltage and charger failure (See Table 2).

No periodic verification of station dc supply voltage is required.

Any battery based station dc supply with electrolyte level
monitoring and alarming in every cell (See Table 2).

No periodic inspection of the electrolyte level for each cell is
required.

Any station dc supply with unintentional dc ground monitoring
and alarming (See Table 2).

No periodic inspection of unintentional dc grounds is required.

Any station dc supply with charger float voltage monitoring
and alarming to ensure correct float voltage is being applied
on the station dc supply (See Table 2).

No periodic verification of float voltage of battery charger is
required.

Any battery based station dc supply with monitoring and
alarming of battery string continuity (See Table 2).

No periodic
maintenance specified

No periodic verification of the battery continuity is required.

Any battery based station dc supply with monitoring and
alarming of the intercell and/or terminal connection detail
resistance of the entire battery (See Table 2).

No periodic verification of the intercell and terminal connection
resistance is required.

Any Valve Regulated Lead-Acid (VRLA) or Vented Lead-Acid
(VLA) station battery with internal ohmic value or float current
monitoring and alarming, and evaluating present values
relative to baseline internal ohmic values for every cell/unit
(See Table 2).

No periodic evaluation relative to baseline of battery cell/unit
measurements indicative of battery performance is required to
verify the station battery can perform as manufactured.

Any Valve Regulated Lead-Acid (VRLA) or Vented Lead-Acid
(VLA) station battery with monitoring and alarming of each
cell/unit internal ohmic value (See Table 2).

No periodic inspection of the condition of all individual units by
measuring battery cell/unit internal ohmic values of a station
VRLA or Vented Lead-Acid (VLA) battery is required.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 1-5
Component Type - Control Circuitry Associated With Protective Functions
Excluding distributed UFLS and distributed UVLS (see Table 3), Automatic Reclosing (see Table 4), and Sudden Pressure Relaying (see Table 5)
Note: Table requirements apply to all Control Circuitry Components of Protection Systems, and RAS except as noted.
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Trip coils or actuators of circuit breakers, interrupting devices, or mitigating
devices (regardless of any monitoring of the control circuitry).

6 Calendar
Years

Verify that each trip coil is able to operate the circuit
breaker, interrupting device, or mitigating device.

Electromechanical lockout devices which are directly in a trip path from the
protective relay to the interrupting device trip coil (regardless of any
monitoring of the control circuitry).

6 Calendar
Years

Verify electrical operation of electromechanical lockout
devices.

(See Table 4-2(b) for RAS which include Automatic Reclosing.)

12 Calendar
Years

Verify all paths of the control circuits essential for proper
operation of the RAS.

Unmonitored control circuitry associated with protective functions inclusive
of all auxiliary relays.

12 Calendar
Years

Verify all paths of the trip circuits inclusive of all auxiliary
relays through the trip coil(s) of the circuit breakers or
other interrupting devices.

Control circuitry associated with protective functions and/or RAS whose
integrity is monitored and alarmed (See Table 2).

No periodic
maintenance
specified

None.

Unmonitored control circuitry associated with RAS.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 2 – Alarming Paths and Monitoring
In Tables 1-1 through 1-5, Table 3, Tables 4-1 through 4-2, and Table 5 alarm attributes used to justify extended maximum maintenance intervals and/or
reduced maintenance activities are subject to the following maintenance requirements
Component Attributes
Any alarm path through which alarms in Tables 1-1 through 1-5, Table 3, Tables
4-1 through 4-2, and Table 5 are conveyed from the alarm origin to the location
where corrective action can be initiated, and not having all the attributes of the
“Alarm Path with monitoring” category below.

Maximum
Maintenance
Interval

12 Calendar Years

Alarms are reported within 24 hours of detection to a location where
corrective action can be initiated.
Alarm Path with monitoring:
The location where corrective action is taken receives an alarm within 24 hours
for failure of any portion of the alarming path from the alarm origin to the
location where corrective action can be initiated.

No periodic
maintenance
specified

Maintenance Activities

Verify that the alarm path conveys alarm signals
to a location where corrective action can be
initiated.

None.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 3
Maintenance Activities and Intervals for distributed UFLS and distributed UVLS Systems
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Verify that settings are as specified.
For non-microprocessor relays:
 Test and, if necessary calibrate.
Any unmonitored protective relay not having all the monitoring attributes of
a category below.

6 Calendar
Years

For microprocessor relays:
 Verify operation of the relay inputs and outputs that are
essential to proper functioning of the Protection System.
 Verify acceptable measurement of power system input
values.

Monitored microprocessor protective relay with the following:

Verify:

 Internal self-diagnosis and alarming (See Table 2).
 Voltage and/or current waveform sampling three or more times per
power cycle, and conversion of samples to numeric values for
measurement calculations by microprocessor electronics.

12 Calendar
Years

 Ac measurements are continuously verified by comparison to an
independent ac measurement source, with alarming for excessive error
(See Table 2).

 Operation of the relay inputs and outputs that are essential
to proper functioning of the Protection System.
 Acceptable measurement of power system input values

Alarming for power supply failure (See Table 2).
Monitored microprocessor protective relay with preceding row attributes
and the following:

 Settings are as specified.

12 Calendar
Years

Verify only the unmonitored relay inputs and outputs that are
essential to proper functioning of the Protection System.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 3
Maintenance Activities and Intervals for distributed UFLS and distributed UVLS Systems
Maximum
Maintenance
Interval

Maintenance Activities

Voltage and/or current sensing devices associated with UFLS or UVLS
systems.

12 Calendar
Years

Verify that current and/or voltage signal values are provided to
the protective relays.

Protection System dc supply for tripping non-BES interrupting devices used
only for a UFLS or UVLS system.

12 Calendar
Years

Verify Protection System dc supply voltage.

Control circuitry between the UFLS or UVLS relays and electromechanical
lockout and/or tripping auxiliary devices (excludes non-BES interrupting
device trip coils).

12 Calendar
Years

Verify the path from the relay to the lockout and/or tripping
auxiliary relay (including essential supervisory logic).

Electromechanical lockout and/or tripping auxiliary devices associated only
with UFLS or UVLS systems (excludes non-BES interrupting device trip coils).

12 Calendar
Years

Verify electrical operation of electromechanical lockout and/or
tripping auxiliary devices.

Control circuitry between the electromechanical lockout and/or tripping
auxiliary devices and the non-BES interrupting devices in UFLS or UVLS
systems, or between UFLS or UVLS relays (with no interposing
electromechanical lockout or auxiliary device) and the non-BES interrupting
devices (excludes non-BES interrupting device trip coils).

No periodic
maintenance
specified

None.

Trip coils of non-BES interrupting devices in UFLS or UVLS systems.

No periodic
maintenance
specified

None.

Component Attributes
 Some or all binary or status inputs and control outputs are monitored by
a process that continuously demonstrates ability to perform as
designed, with alarming for failure (See Table 2).
Alarming for change of settings (See Table 2).

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 4-1
Maintenance Activities and Intervals for Automatic Reclosing Components
Component Type – Reclosing Relay
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Verify that settings are as specified.
For non-microprocessor relays:
Any unmonitored reclosing relay not having all the monitoring attributes of a
category below.

6 Calendar
Years

 Test and, if necessary calibrate
For microprocessor relays:
 Verify operation of the relay inputs and outputs that are
essential to proper functioning of the Automatic Reclosing.

Monitored microprocessor reclosing relay with the following:
 Internal self-diagnosis and alarming (See Table 2).
 Alarming for power supply failure (See Table 2).

Verify:
12 Calendar
Years

 Settings are as specified.
 Operation of the relay inputs and outputs that are essential
to proper functioning of the Automatic Reclosing.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 4-2(a)
Maintenance Activities and Intervals for Automatic Reclosing Components
Component Type – Control Circuitry Associated with Reclosing Relays that are NOT an Integral Part of an RAS
Maximum
Maintenance
Interval

Maintenance Activities

Unmonitored Control circuitry associated with Automatic Reclosing that is
not an integral part of an RAS.

12 Calendar
Years

Verify that Automatic Reclosing, upon initiation, does not
issue a premature closing command to the close circuitry.

Control circuitry associated with Automatic Reclosing that is not part of an
RAS and is monitored and alarmed for conditions that would result in a
premature closing command. (See Table 2)

No periodic
maintenance
specified

None.

Component Attributes

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 4-2(b)
Maintenance Activities and Intervals for Automatic Reclosing Components
Component Type – Control Circuitry Associated with Reclosing Relays that ARE an Integral Part of an RAS
Component Attributes

Maximum
Maintenance
Interval

Maintenance Activities

Close coils or actuators of circuit breakers or similar devices that are used in
conjunction with Automatic Reclosing as part of an RAS (regardless of any
monitoring of the control circuitry).

6 Calendar
Years

Verify that each close coil or actuator is able to operate the
circuit breaker or mitigating device.

Unmonitored close control circuitry associated with Automatic Reclosing
used as an integral part of an RAS.

12 Calendar
Years

Verify all paths of the control circuits associated with Automatic
Reclosing that are essential for proper operation of the RAS.

Control circuitry associated with Automatic Reclosing that is an integral part
of an RAS whose integrity is monitored and alarmed. (See Table 2)

No periodic
maintenance
specified

None.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Table 5
Maintenance Activities and Intervals for Sudden Pressure Relaying
Note: In cases where Components of Sudden Pressure Relaying are common to Components listed in Table 1-5, the Components only need to be tested once
during a distinct maintenance interval.
Component Attributes

Maximum Maintenance
Interval

Maintenance Activities

Any fault pressure relay.

6 Calendar Years

Verify the pressure or flow sensing mechanism is operable.

Electromechanical lockout devices which are directly in a
trip path from the fault pressure relay to the interrupting
device trip coil (regardless of any monitoring of the control
circuitry).

6 Calendar Years

Verify electrical operation of electromechanical lockout devices.

Unmonitored control circuitry associated with Sudden
Pressure Relaying.

12 Calendar Years

Verify all paths of the trip circuits inclusive of all auxiliary relays
through the trip coil(s) of the circuit breakers or other interrupting
devices.

Control circuitry associated with Sudden Pressure Relaying
whose integrity is monitored and alarmed (See Table 2).

No periodic maintenance
specified

None.

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

Rationale:
During development of this standard, text boxes were embedded within the standard to explain
the rationale for various parts of the standard. Upon BOT approval, the text from the rationale
text boxes was moved to this section.
Rationale for Applicability Section:
This section does not reflect the applicability changes that will be proposed by the Project
2014-01 Standards Applicability for Dispersed Generation Resources standards drafting team.
The changes in this posted version and those being made by the Project 2014-01 standards
drafting team do not overlap.
Additionally, to align with ongoing NERC standards development in Project 2010-05.2: Special
Protection Systems, the term “Special Protection Systems” in PRC-005-4 was replaced by the
term “Remedial Action Schemes.” These terms are synonymous in the NERC Glossary of Terms.
Rationale for the deletion of part of the definition of Component:
The SDT determined that it was explanatory in nature and adequately addressed in the
Supplementary Reference and FAQ Document.
Rationale for R3 Part 3.1:
In the last posting, the SDT included language in the standard that was originally in the
implementation plan that required completion of maintenance activities within three years for
newly-identified Automatic Reclosing Components following a notification under Requirement
R6, which has been removed. After further discussion, the SDT determined that a separate
shorter timeframe for maintenance of newly-identified Automatic Reclosing Components
created unnecessary complication within the standard. The SDT agreed that entities should be
responsible for maintaining the Automatic Reclosing Components subject to the standard,
whether existing, newly added or newly within scope based on a change in the largest
generating unit in the BA or, if a member of a Reserve Sharing Group, the largest generating
unit within the Reserve Sharing Group according to the timeframes in the maintenance
tables. Therefore, 3.1 and its subparts have been removed and have not been reinserted into
the implementation plan.
Rationale for R4 Part 4.1:
In the last posting, the SDT included language in the standard that was originally in the
implementation plan that required completion of maintenance activities within three years for
newly-identified Automatic Reclosing Components following a notification under Requirement
R6, which has been removed. After further discussion, the SDT determined that a separate
shorter timeframe for maintenance of newly-identified Automatic Reclosing Components
created unnecessary complication within the standard. The SDT agreed that entities should be
responsible for maintaining the Automatic Reclosing Components subject to the standard,
whether existing, newly added or newly within scope based on a change in the largest
generating unit in the BA or, if a member of a Reserve Sharing Group, the largest generating

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Standard PRC-005-4 – Protection System, Automatic Reclosing, and Sudden Pressure Relaying Maintenance

unit within the Reserve Sharing Group according to the timeframes in the maintenance
tables. Therefore, 4.1 and its subparts have been removed and have not been reinserted into
the implementation plan.

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Application Guidelines

PRC-005 — Attachment A
Criteria for a Performance-Based Protection System Maintenance Program
Purpose: To establish a technical basis for initial and continued use of a performance-based
Protection System Maintenance Program (PSMP).
To establish the technical justification for the initial use of a performance-based PSMP:
1. Develop a list with a description of Components included in each designated Segment,
with a minimum Segment population of 60 Components.
2. Maintain the Components in each Segment according to the time-based maximum
allowable intervals established in Tables 1-1 through 1-5, Table 3, Tables 4-1 through 42, and Table 5 until results of maintenance activities for the Segment are available for a
minimum of 30 individual Components of the Segment.
3. Document the maintenance program activities and results for each Segment, including
maintenance dates and Countable Events for each included Component.
4. Analyze the maintenance program activities and results for each Segment to determine
the overall performance of the Segment and develop maintenance intervals.
5. Determine the maximum allowable maintenance interval for each Segment such that
the Segment experiences Countable Events on no more than 4% of the Components
within the Segment, for the greater of either the last 30 Components maintained or all
Components maintained in the previous year.
To maintain the technical justification for the ongoing use of a performance-based PSMP:
1. At least annually, update the list of Components and Segments and/or description if any
changes occur within the Segment.
2. Perform maintenance on the greater of 5% of the Components (addressed in the
performance based PSMP) in each Segment or 3 individual Components within the
Segment in each year.
3. For the prior year, analyze the maintenance program activities and results for each
Segment to determine the overall performance of the Segment.
4. Using the prior year’s data, determine the maximum allowable maintenance interval for
each Segment such that the Segment experiences Countable Events on no more than
4% of the Components within the Segment, for the greater of either the last 30
Components maintained or all Components maintained in the previous year.
If the Components in a Segment maintained through a performance-based PSMP experience
4% or more Countable Events, develop, document, and implement an action plan to reduce the
Countable Events to less than 4% of the Segment population within 3 years.

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