NERC Petition for PRC-010-1

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-010-1 (UNDERVOLTAGE LOAD SHEDDING)
Gerald W. Cauley
President and Chief Executive Officer
North American Electric Reliability
Corporation
3353 Peachtree Road, N.E.
Suite 600, North Tower
Atlanta, GA 30326
(404) 446-2560
(404) 446-2595 – facsimile

Charles A. Berardesco
Senior Vice President and General Counsel
Holly A. Hawkins
Associate General Counsel
William H. Edwards
Counsel
North American Electric Reliability
Corporation
1325 G Street, N.W., Suite 600
Washington, D.C. 20005
(202) 400-3000
(202) 644-8099 – facsimile
[email protected]
[email protected]
[email protected]

Counsel for the North American Electric
Reliability Corporation

February 6, 2015

TABLE OF CONTENTS

I.

Executive Summary ................................................................................................................ 3

II.

Notices and Communications ................................................................................................. 4

III. 2003 Blackout Report ............................................................................................................. 4
A.

Recommendation 21B ...................................................................................................... 4

B.

Recommendation 21C ...................................................................................................... 6

IV. Order No. 693 and Description of UVLS-Related Standards ................................................. 7
C.

PRC-010-0 ........................................................................................................................ 8

D.

PRC-020-1 ........................................................................................................................ 9

E.

PRC-021-1 ........................................................................................................................ 9

F. PRC-022-1 ......................................................................................................................... 10
V.

Reliability Standard Development Background ................................................................... 10
A.

Regulatory Framework ................................................................................................... 10

B.

NERC Reliability Standards Development Procedure ................................................... 11

C.

Project 2008-02 – Undervoltage Load Shedding ........................................................... 12

VI. Justification for Approval ..................................................................................................... 13
A.

Proposed Reliability Standard PRC-010-1..................................................................... 14
1.

Proposed Defined Term and Requirements ................................................................ 15

2.

Proposed Requirements .............................................................................................. 17

B.

Misoperation of UVLS Equipment ................................................................................ 23

C.

Enforceability of Proposed Reliability Standard ............................................................ 24

VII. Conclusion ............................................................................................................................ 24

Exhibit A

Proposed Reliability Standard PRC-010-1

Exhibit B

Implementation Plan

Exhibit C

Mapping Document

Exhibit D

Order No. 672 Criteria

Exhibit E

Analysis of Violation Risk Factors and Violation Security Levels

Exhibit F

Summary of Development History and Complete Record of Development

Exhibit G

PRC-010-1 Frequently Asked Questions
i

TABLE OF CONTENTS
Exhibit H

Standard Drafting Team Roster

Exhibit I

NERC SPCS Technical Review of UVLS-Related Standards: PRC-010-0, PRC
020-1, PRC-021-1, and PRC-022-1

ii

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-010-1 (UNDERVOLTAGE LOAD SHEDDING)
Pursuant to Section 215(d)(1) of the Federal Power Act (“FPA”)1 and Section 39.52 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-010-1 (Undervoltage Load Shedding) (Exhibit A). NERC
requests that the Commission approve the proposed Reliability Standard and find that it is just,
reasonable, not unduly discriminatory or preferential, and in the public interest.4 NERC also
requests approval of: (i) a revised definition of “Undervoltage Load Shedding Program (UVLS
Program)” for inclusion in the NERC Glossary of Terms; (ii) the Implementation Plan for the
proposed Reliability Standard (Exhibit B); and (iii) the associated Violation Risk Factors
(“VRFs”) and Violation Severity Levels (“VSLs”) (Exhibits A and E). Finally, NERC requests

1

16 U.S.C. § 824o (2012).
18 C.F.R. § 39.5 (2014).
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

retirement of the following Undervoltage Load Shedding (“UVLS”) Reliability Standards (the
“UVLS-Related Standards”), as listed in the Implementation Plan:
•
•
•
•

PRC-010-0 – Assessment of the Design and Effectiveness of UVLS Program;
PRC-020-1 – Under-Voltage Load Shedding Program Database;
PRC-021-1 – Under-Voltage Load Shedding Program Data; and
PRC-022-1 – Under-Voltage Load Shedding Program Performance.
Prior to the discussion of proposed Reliability Standard PRC-010-1 below, NERC

provides a summary of the recommendations related to UVLS made in the U.S.-Canada Power
System Outage Task Force (“Task Force”) Final Report on the August 14, 2003 Blackout in the
United States and Canada: Causes and Recommendations (“2003 Blackout Report”)5 and NERC
actions taken in response to those recommendations. NERC also summarizes the Commission’s
determinations in Order No. 6936 for Reliability Standards related to UVLS. As explained
below, the proposed PRC-010-1 Reliability Standard reflects consideration of the 2003 Blackout
Report recommendations and the Commission determinations in Order No. 693.
As required by Section 39.5(a)7 of the Commission’s regulations, this petition, in Section
IV, presents the technical basis and purpose of proposed Reliability Standard PRC-010-1, a
summary of the development history (Exhibit F), and a demonstration that the proposed
Reliability Standard meets the criteria identified by the Commission in Order No. 6728 (Exhibit
D). The NERC Board of Trustees (“Board”) adopted proposed Reliability Standard PRC-010-1
on November 13, 2014.

5
U.S.-Canada Power System Outage Task Force, Final Report on the August 14, 2003 Blackout in the
United States and Canada: Causes and Recommendations, Apr. 2004.
6
Mandatory Reliability Standards for the Bulk-Power System, Order No. 693, 118 FERC ¶ 61,218 (2007).
7
18 C.F.R. § 39.5(a) (2014).
8
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).

2

I.

Executive Summary
Proposed Reliability Standard PRC‐010‐1 is a single, comprehensive standard that

addresses the same reliability principles outlined in the UVLS-Related Reliability Standards,
PRC‐010‐0, PRC‐020‐1, PRC‐021‐1, and PRC‐022‐1. The purpose of PRC-010-1 is to
“establish an integrated and coordinated approach to the design, evaluation, and reliable
operation of Undervoltage Load Shedding Programs (UVLS Programs).” Proposed PRC‐010‐1
represents an improvement to the prior set of UVLS-Related Standards. Proposed PRC-010-1
addresses the Commission directive in Order No. 693, Paragraph 1509 to modify PRC‐010‐0 to
require an integrated and coordinated approach to all protection systems. The proposed
Reliability Standard also replaces the applicability to and involvement of the “Regional
Reliability Organization” in Reliability Standards PRC‐020‐1 and PRC‐021‐1 and consolidates
the UVLS‐Related Standards into one comprehensive standard. The proposed Reliability
Standard incorporates the proposed definition of “UVLS Program”, which clearly identifies and
separates centrally controlled undervoltage‐based load shedding, which is now addressed by the
proposed definition of “Remedial Action Scheme.”
The proposed Reliability Standard requires applicable entities to evaluate a UVLS
Program’s effectiveness prior to implementation, including the UVLS Program’s coordination
with other Protection Systems and generator voltage ride through capabilities. Proposed PRC010-1 also requires UVLS entities to adhere to UVLS Program specifications and the
implementation schedule. In addition, applicable entities must perform periodic assessment and
performance analysis of UVLS Programs and resolve identified deficiencies. Finally, applicable
entities must maintain and share UVLS Program data.

3

II.

Notices and Communications
Notices and communications with respect to this filing may be addressed to the

following:9

Charles A. Berardesco*
Senior Vice President and General Counsel
Holly A. Hawkins*
Associate General Counsel
William H. Edwards*
Counsel
North American Electric Reliability
Corporation
1325 G Street, N.W., Suite 600
Washington, D.C. 20005
(202) 400-3000
(202) 644-8099 – facsimile
[email protected]
[email protected]
[email protected]

III.

Valerie L. Agnew*
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
[email protected]

2003 Blackout Report

In the 2003 Blackout Report, the Task Force included Recommendation 21 to “make
more effective and wider use of system protection measures.”10 In addition, the Task Force
added three additional recommendations, Recommendation 21A–21C. Recommendations 21B
and 21C include actions related to UVLS.
A.

Recommendation 21B

The 2003 Blackout Report identifies that NERC, in support of Recommendation 21,
required each regional reliability council to evaluate the feasibility and benefits of UVLS
capability in load centers that could become unstable as a result of insufficient reactive power

9

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 (2014), to allow the inclusion
of more than two persons on the service list in this proceeding.
10
2003 Blackout Report at 3, 158.

4

following credible multiple-contingency events. NERC instructed the regional reliability
councils to complete the initial studies and report the results to NERC within one year. NERC
also provided that the regions should, where beneficial, promote the installation of UVLS
capabilities in critical areas, as determined by the studies, as an effective way to in prevent or
contain an uncontrolled cascade of the power system.11
The Task Force recommended, via Recommendation 21B in the 2003 Blackout Report,
that NERC require the results of the regional studies to be provided to federal and state or
provincial regulators at the same time that they are reported to NERC. In addition, the Task
Force recommended that NERC require every entity with a new or existing UVLS program to
have a well-documented set of guidelines that specify the conditions and triggers for UVLS
use.12
Following the issuance of Recommendation 21B, the Board, at its February 2006
meeting, approved a resolution to implement the recommendations contained in the Review of
Regional Evaluations of Undervoltage Load Shedding Capability in Response to NERC Blackout
Recommendation 8b (“Recommendation 8b Report”), which was developed by the NERC
Planning Committee.13 The Board resolution:
•

directed the Planning Committee to develop by the end of 2006 a comprehensive set of
study guidelines for use in future evaluations of the need and benefit of implementing
undervoltage load shedding (UVLS) systems;

•

requested each regional reliability council, in conjunction with its members, to develop
implementation plans and schedules to install UVLS capability in those load centers
where regional studies have identified UVLS as feasible and beneficial to preventing

11

Id. at 158 (summarizing NERC actions related to Recommendation 21 on evaluation of the applicability of
UVLS). See also NERC, August 14, 2003 Blackout: NERC Actions to Prevent and Mitigate the Impacts of Future
Cascading Blackouts, Feb. 2004 at 12 (summarizing NERC recommendation 8b, which tracks to Recommendation
21B of the 2003 Blackout Report) (“NERC Blackout Recommendations Report”).
12
2003 Blackout Report at 159.
13
See U.S.-Canada Power System Outage Task Force, Final Report on Implementation of Task Force
Recommendations, Sept. 2006, at 31-32; see also NERC Board Feb. 7, 2006 Resolution on the Blackout
Recommendation 8b Report, available at http://www.nerc.com/gov/bot/Pages/AgendasHighlightsMinutes.aspx.

5

instability and to provide these plans and schedules to the Planning Committee for review
by June 2006;
•

directed the Planning Committee to review and report to the Board at its August 2006
meeting on the regional UVLS implementation plans and schedules;

•

directed the Planning Committee to survey the existing UVLS systems installed on the
Bulk Electric System, to continue to monitor future installations, and support potential
future standards activities in this area; and

•

directed the Planning Committee to survey the status of research and development efforts
on methods to more accurately determine and model load characteristics and to report to
the Board at its November 2006 meeting on the results of those efforts.
As noted in the Task Force’s Final Report on Implementation of Recommendations

(“Blackout Implementation Report”), no further action beyond the actions directed by the Board
were required to fully implement Recommendation 21B.14
B.

Recommendation 21C

The 2003 Blackout Report also identified that NERC, in support of Recommendation 21,
planned to evaluate Planning Standard III, System Protection and Control, and propose specific
revisions to the criteria to address adequately the issue of slowing or limiting the propagation of
a cascading failure.15
The Task Force further recommended, in Recommendation 21C, that NERC determine
the goals and principles needed to establish an integrated approach to relay protection for
generators and transmission lines, as well as the use of UFLS and UVLS programs. The Task
Force explained that an integrated approach was necessary to ensure that at the local and regional
level, these interactive components would provide an appropriate balance of risks and benefits in
terms of protecting specific assets and facilitating overall grid survival. The Task Force stated

14

See Blackout Implementation Report at 31 (Sept. 2006), available at
http://energy.gov/sites/prod/files/oeprod/DocumentsandMedia/BlackoutFinalImplementationReport(2).pdf
15
2003 Blackout Report at 159; see also NERC Blackout Recommendations Report at 13 (summarizing
NERC Recommendation 8C, which tracks to Recommendation 21C).

6

that the review should include an assessment of the appropriate role and scope of UFLS and
UVLS, and the appropriate use of time delays in relays. In addition, the task force recommended
that in this effort, NERC should work with industry and government research organizations to
assess the applicability of existing and new technology to make the interconnections less
susceptible to cascading outages.
The NERC Planning Committee, at its December 2005 meeting, approved the
recommendations of its own blackout recommendations review task force. The NERC Planning
Committee’s task force also developed an assignment matrix as to which subgroups of the
Planning Committee and Operating Committee would address the twenty-four NERC-identified
recommendations. The Blackout Implementation Report indicates that completion of the work
recommended by the Planning Committee and approval by the Board will constitute full
implementation of Recommendation 21C.16
IV.

Order No. 693 and Description of UVLS-Related Standards
Following the 2003 Blackout Report, the Commission has demonstrated its support of

NERC’s efforts in addressing Recommendation 21 and the creation of mandatory Reliability
Standards for UVLS. While the Commission generally viewed the UVLS-Related Standards as
improving the reliability of the Bulk-Power System, the Commission did identify one area to
focus on for the future. In the Staff Preliminary Assessment of the North American Electric
Reliability Council’s Proposed Mandatory Reliability Standards (“Staff Preliminary
Assessment”),17 the Commission stated the following regarding UFLS, UVLS, line protection
and generation protection:

16

Blackout Implementation Report at 31-32.
See Staff Preliminary Assessment of the North American Electric Reliability Council’s Proposed
Mandatory Reliability Standards, May 11, 2006, Docket No. RM06-16-000.

17

7

UFLS and UVLS act as a safety net for the grid. Generation
protection systems disconnect the generator to prevent damage to
the generator. Line protection systems are designed to sense faults
in the lines and, where detected, take the faulty line out of service.
An integrated and coordinated approach between UFLS, UVLS, line
protection and generation protection is needed to “ensure that at the
local and regional level these interactive components provide an
appropriate balance of risks and benefits in terms of protecting
specific assets and facilitating overall grid survival.” 18
In Order No. 693, the Commission ultimately approved Reliability Standards PRC-010-0,
PRC-021-1, and PRC-022-1.19 However, the Commission neither approved nor remanded PRC020-1 since the Reliability Standard only applied to Regional Reliability Organizations.20 A
summary of each of the UVLS-Related Standard is included below for background.
C.

PRC-010-0

Reliability Standard PRC-010-0 requires Distribution Providers, Load Serving Entities,
Transmission Operators, and Transmission Owners, to periodically assess and document the
effectiveness of its program in coordination with its associated Transmission Planner and
Planning Authority. The Reliability Standard contains one Requirement21 and applies to a LoadServing Entity that operates a UVLS program, a Transmission Owner that owns a UVLS
program, a Transmission Operator that operates a UVLS program, and a Distribution Provider
that owns or operates a UVLS program.
In its determination approving the PRC-010-0 Reliability Standard, the Commission
directed NERC to develop a modification to PRC-010-0 through the Reliability Standards

18

Id. (citing 2003 Blackout Report at 159).
Order No. 693 at PP 1509, 1560, 1565.
20
Id. at 1555.
21
Requirement R2 and the associated elements were approved by the Commission for retirement as part of
the Paragraph 81 project. See Electric Reliability Organization Proposal to Retire Requirements in Reliability
Standards Order No. 788, 145 FERC ¶ 61,147 (2013).
19

8

development process that “requires that an integrated and coordinated approach be included in
all protection systems on the Bulk-Power System, including generators and transmission lines,
generators’ low voltage ride-through capabilities, and UFLS and UVLS programs.”22 The
Commission determination also referenced its prior position in the NOPR and stated that “NERC
is continuing to develop an integrated and coordinated approach to protection for generators,
transmission lines and UFLS and UVLS programs within its work on the fill-in-the-blank
proposed Reliability Standards.”23
D.

PRC-020-1

Reliability Standard PRC-020-1 ensures that a regional database for
UVLS programs is available for Bulk-Power System studies by requiring Regional Reliability
Organizations with any entities that have UVLS programs to maintain and annually update a
database. The Reliability Standard contains two Requirements and applies to any Regional
Reliability Organization with entities that own or operate a UVLS program.
E.

PRC-021-1

Reliability Standard PRC-021-1 requires entities to supply data support the regional
undervoltage load shedding database by requiring the owner of such a system to supply data
related to its system and other related protection schemes to its regional reliability organization’s
database. The Reliability Standard includes two Requirements and applies to Transmission
Owners that own a UVLS program and Distribution Providers that own a UVLS program. In
Order No. 693, the Commission did not issue directives on the Reliability Standard.

22
23

Id.
Order No. 693 at P 1508 (citing P 883 of the NOPR and the Recommendation 8b Report follow-up work).

9

F.

PRC-022-1

Reliability Standard PRC-022-1 requires entities to ensure that undervoltage load
shedding programs perform as intended by requiring each entity that operates such a program to
analyze and document all of its operations and misoperations and develop a corrective action
plan to avoid future misoperations. The Reliability Standard includes one Requirement and
applies to Transmission Operators that operate a UVLS program, Distribution Providers that
operate a UVLS program, and Load-Serving Entities that operate a UVLS program.24
In Order No. 693, the Commission did not issue a directive to modify the Reliability
Standard. However, the Commission did direct NERC to consider comments made by
FirstEnergy during the Reliability Standards development process. FirstEnergy summarized that
Requirement R1.3 of PRC-022-1 requires “a simulation of the event, if deemed appropriate by
the RRO” and believes that the applicable entities such as transmission operators may not be able
to simulate large system events.”25 FirstEnergy suggested that Requirement R1.3 be revised to
state that “a simulation of the event, if deemed appropriate, and assisted by the [regional
reliability organization].”26
V.

Reliability Standard Development Background
A.

Regulatory Framework

By enacting the Energy Policy Act of 2005,27 Congress entrusted the Commission with
the duties of approving and enforcing rules to ensure the reliability of the Nation’s Bulk-Power
System, and with the duties of certifying an Electric Reliability Organization (“ERO”) that

24
25
26
27

Requirement R2 was retired as part of the Paragrpah 81 Project previously approved by the Commission.
Order No. 693 at P 1564.
Id.
16 U.S.C. § 824o (2012).

10

would be charged with developing and enforcing mandatory Reliability Standards, subject to
Commission approval. Section 215(b)(1)28 of the FPA states that all users, owners, and
operators of the Bulk-Power System in the United States will be subject to Commissionapproved Reliability Standards. Section 215(d)(5)29 of the FPA authorizes the Commission to
order the ERO to submit a new or modified Reliability Standard. Section 39.5(a)30 of the
Commission’s regulations requires the ERO to file with the Commission for its 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 should be
made effective.
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 FPA31 and Section 39.5(c)32 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.33 NERC

28

Id. § 824(b)(1).
Id. § 824o(d)(5).
30
18 C.F.R. § 39.5(a).
31
16 U.S.C. § 824o(d)(2).
32
18 C.F.R. § 39.5(c)(1).
33
Rules Concerning Certification of the Electric Reliability Organization; and Procedures for the
Establishment, Approval, and Enforcement of Electric Reliability Standards, Order No. 672 at P 334, FERC Stats. &
Regs. ¶ 31,204, order on reh’g, Order No. 672-A, FERC Stats. & Regs. ¶ 31,212 (2006) (“Further, in considering
whether a proposed Reliability Standard meets the legal standard of review, we will entertain comments about
whether the ERO implemented its Commission-approved Reliability Standard development process for the
29

11

develops Reliability Standards in accordance with Section 300 (Reliability Standards
Development) of its Rules of Procedure and the NERC Standard Processes Manual.34 In its
order certifying NERC as the Commission’s ERO, the Commission found that NERC’s proposed
rules provide for reasonable notice and opportunity for public comment, due process, openness,
and a balance of interests in developing Reliability Standards35 and thus satisfies certain of the
criteria for approving Reliability Standards.36 The development process is open to any person or
entity with a legitimate interest in the reliability of the Bulk-Power System. NERC considers the
comments of all stakeholders, and stakeholders must approve, and the NERC Board of Trustees
must adopt a Reliability Standard before the Reliability Standard is submitted to the Commission
for approval.
C.

Project 2008-02 – Undervoltage Load Shedding

NERC Project 2008-02 was established to modify the UVLS-Related Standards to
establish an integrated and coordinated approach to the design, evaluation, and reliable operation
of UVLS programs that are used to mitigate undervoltage conditions leading to voltage
instability, voltage collapse, or Cascading on the Bulk Electric System. The standard drafting
team for Project 2008-02 aimed to consolidate the existing UVLS-Related Standards to create
one comprehensive standard and eliminate the Regional Reliability Organization as an applicable
entity in Reliability Standard PRC-020-1. The standard drafting team sought to create a resultsbased standard that clearly defines the responsibilities of applicable entities to:

development of the particular proposed Reliability Standard in a proper manner, especially whether the process was
open and fair. However, we caution that we will not be sympathetic to arguments by interested parties that choose,
for whatever reason, not to participate in the ERO’s Reliability Standard development process if it is conducted in
good faith in accordance with the procedures approved by FERC.”).
34
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.
35
116 FERC ¶ 61,062 at P 250.
36
Order No. 672 at PP 268, 270.

12

•

pursue an integrated and coordinated approach to the design, evaluation, and reliable
operation of automatic, distributed UVLS programs;

•

ensure the coordination of automatic, distributed, UVLS programs with generator
voltage ride-through capabilities and protection and control systems; and

•

establish proper and meaningful automatic, distributed UVLS database requirements.

To accomplish these goals, the standard drafting team considered input from a variety of sources
including the 2003 Blackout Report, Commission guidance in Order No. 693, and
recommendations from the NERC System Protection and Control Subcommittee (“SPCS”) in its
December 2010 NERC SPCS Technical Review of UVLS-Related Standards: PRC-010-0, PRC020-1, PRC-021-1, and PRC-022-1 (“SPCS Technical Review”).37 The SPCS Technical Review
is included as Exhibit I. The SPCS Technical Review recommended: (1) combining the four existing
UVLS Reliability Standards; (2) revising the applicability to entities responsible for UVLS program
design, implementation, and coordination; (3) including a requirement for assessment of coordination
between UVLS programs and all other protection systems; and (4) differentiating post‐event validation of
UVLS program design from verifying correct operation of UVLS equipment.

VI.

Justification for Approval
As discussed in Exhibit D and below, the proposed Reliability Standard PRC-010-1 and

the definition of “UVLS Program” satisfy the Commission’s criteria in Order No. 672 and are
just, reasonable, not unduly discriminatory or preferential, and in the public interest. The
following section provides a description of and the technical basis for the proposed definition
and Requirements, and describes how the proposed Reliability Standard and associated definition
improve reliability and support Recommendation 21 of the 2003 Blackout Report. This section
also provides a brief summary of how the proposed Reliability Standards satisfy the outstanding

37

See
http://www.nerc.com/comm/PC/System%20Protection%20and%20Control%20Subcommittee%20SPCS%20DL/PR
C-010_022%20Report_Approved_20101208.pdf.

13

Commission directives from Order No. 693 related to the UVLS-Related Standards. Finally, this
section includes a discussion of the enforceability of the proposed Reliability Standard.
A.

Proposed Reliability Standard PRC-010-1

Proposed Reliability Standard PRC‐010‐1 is a single, comprehensive standard that
addresses the same reliability principles outlined in the UVLS-Related Reliability Standards,
PRC‐010‐0, PRC‐020‐1, PRC‐021‐1, and PRC‐022‐1. The standard drafting team developed
PRC-010-1 using PRC‐006‐1 (Automatic Underfrequency Load Shedding) as a model.
Understanding that UVLS and UFLS systems have fundamental differences, the drafting team
adopted the industry‐vetted reliability principles and language of PRC-006-1 as applicable to
UVLS Programs. The need for and design of UVLS Programs is unique to each system
preservation footprint. As a result, the proposed Reliability Standard provides a framework of
reliability requirements for such programs to which each individual entity can apply its
program’s specific considerations and characteristics. Proposed PRC-010-1 does not, however,
require a mandatory UVLS Program, nor does this standard address whether an entity needs to
employ an UVLS Program. PRC‐010‐1 applies only after an entity has determined the need for
a UVLS Program as a result of its own planning studies.
The purpose of PRC-010-1 is to “establish an integrated and coordinated approach to the
design, evaluation, and reliable operation of Undervoltage Load Shedding Programs (UVLS
Programs).” Proposed PRC‐010‐1 represents an improvement to the prior set of UVLS-Related
Standards. Proposed PRC-010-1 addresses the Commission directive in Order No. 693,
Paragraph 1509 to modify PRC‐010‐0 to require an integrated and coordinated approach to all
protection systems. The proposed Reliability Standard also replaces the applicability to and
involvement of the “Regional Reliability Organization” in Reliability Standards PRC‐020‐1 and

14

PRC‐021‐1 and consolidates the UVLS‐Related Standards into one comprehensive standard.
The proposed Reliability Standard incorporates the proposed definition of “UVLS Program”,
which clearly identifies and separates centrally controlled undervoltage‐based load shedding,
which is now addressed by the proposed definition of “Remedial Action Scheme.”
The proposed Reliability Standard applies to Planning Coordinators and Transmission
Planners. The applicability includes both the Planning Coordinator and Transmission Planner
because either may be responsible for designing and coordinating the UVLS Program. Proposed
PRC-010-1 also applies to Distribution Providers and Transmission Owners responsible for the
ownership, operation, or control of UVLS equipment as required by the UVLS Program
established by the Transmission Planner or Planning Coordinator. These Distribution Providers
and Transmission Owners are referred to as “UVLS entities” within the Applicability section of
proposed Reliability Standard PRC-010-1. The phrase “Planning Coordinator or Transmission
Planner” within the description of “UVLS entities” in the applicability section provides the
latitude for applicability to the entity that will perform the action. The expectation is not that
both parties will perform the action, but rather that the Planning Coordinator or Transmission
Planner that establishes the UVLS Program will be responsible for identifying the UVLS
equipment and the necessary Distribution Providers and Transmission Owners.
1.

Proposed Defined Term and Requirements
a)

Proposed Defined Term “UVLS Program”

A proposed definition of “Undervoltage Load Shedding Program (UVLS Program)” has
been introduced and incorporated into the proposed Requirements. This proposed definition sets
the parameters for which UVLS systems fall within the scope of the proposed PRC-010-1
Requirements. The proposed defined term reads:

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Undervoltage Load Shedding Program (UVLS Program): An
automatic load shedding program, consisting of distributed relays
and controls, used to mitigate undervoltage conditions impacting the
Bulk Electric System (BES), leading to voltage instability, voltage
collapse, or Cascading. Centrally controlled undervoltage‐based
load shedding is not included.
The standard drafting team found it necessary to introduce the term “UVLS Program”
because different types of UVLS systems need to be treated appropriately with respect to
mandatory reliability requirements. The definition for the term UVLS Program includes
automatic load shedding programs that utilize only voltage inputs at locations where action is
taken to shed load. To ensure that the applicability of the proposed Reliability Standard covers
undervoltage‐based load shedding systems whose performance has an impact on system
reliability, a UVLS Program must mitigate risk of one or more of the following: voltage
instability, voltage collapse, or Cascading impacting the Bulk Electric System. By focusing on
the enumerated risks, the definition is meant to inherently exclude locally‐applied relays that are
designed to protect a contained area or, in other words, are not designed to mitigate wide‐area
voltage collapse. An example of a program that would not fall under this category is
undervoltage‐based load shedding installed to mitigate damage to equipment or local loads that
are directly affected by the low voltage event.
The definition for the term UVLS Program excludes centrally controlled undervoltage‐
based load shedding, which utilizes inputs from multiple locations and may also utilize inputs
other than voltages (such as generator reactive reserves, facility loadings, equipment statuses,
etc.). The design and characteristics of a centrally controlled undervoltage‐based load shedding
system are the same as that of a Remedial Action Scheme, wherein load shedding is the remedial
action. Therefore, just like for a Remedial Action Scheme, the failure of a single component can
compromise the reliable operation of centrally controlled undervoltage‐based load shedding.
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This type of UVLS system now falls within the scope of the proposed definition of Remedial
Action Scheme, which is also pending approval with the Commission.
Of note, the definition of UVLS Program is independent of whether the undervoltage
load shedding relays are armed manually or automatically since the arming is done in
anticipation of extreme conditions and not during the events when load shedding needs to occur.
2.

Proposed Requirements

Although the use of UVLS is not mandatory under the proposed Reliability Standard, if it
is determined that this system preservation measure is necessary to support reliability and a
UVLS Program is installed, the UVLS Program needs to be properly coordinated, implemented,
and assessed due to the inherent associated reliability risks. As such, there needs to be a level of
performance required to properly protect system reliability. The Requirements of proposed
Reliability Standard PRC‐010‐1 meet four primary objectives. First, the proposed Reliability
Standard requires applicable entities to evaluate a UVLS Program’s effectiveness prior to
implementation, including the UVLS Program’s coordination with other Protection Systems and
generator voltage ride through capabilities. Second, applicable entities must adhere to UVLS
Program specifications and the implementation schedule. Third, applicable entities must
perform periodic assessment and performance analysis of UVLS Programs and resolve identified
deficiencies. Finally, applicable entities must maintain and share UVLS Program data.
a)

Requirement R1

R1. Each Planning Coordinator or Transmission Planner that is
developing a UVLS Program shall evaluate its effectiveness and
subsequently provide the UVLS Program’s specifications and
implementation schedule to the UVLS entities responsible for
implementing the UVLS Program. The evaluation shall include,
but is not limited to, studies and analyses that show: [Violation
Risk Factor: High] [Time Horizon: Long‐term Planning]
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1.1. The implementation of the UVLS Program resolves the
identified undervoltage issues that led to its development
and design.
1.2. The UVLS Program is integrated through coordination
with generator voltage ride‐through capabilities and other
protection and control systems, including, but not limited
to, transmission line protection, autoreclosing, Remedial
Action Schemes, and other undervoltage‐based load
shedding programs.

Proposed Requirement R1 requires each Planning Coordinator or Transmission Planner
that develops a UVLS Program to evaluate the viability and effectiveness of the UVLS Program
before implementation. This evaluation must include, but is not limited to whether
implementation of the program resolves the identified undervoltage conditions that led to its
design, and whether the UVLS Program is integrated through coordination with generator
voltage ride-through capabilities and other protection and control systems. Though presented as
separate subparts in the proposed Requirement, the studies that show coordination considerations
and that the program addresses undervoltage issues may be interrelated and presented as one
comprehensive analysis.
Proposed Requirement R1 also requires the Planning Coordinator or Transmission
Planner to provide the UVLS Program’s specifications and implementation schedule to
applicable UVLS entities to implement the program. It is noted that studies to evaluate the
effectiveness of the program must be completed prior to providing the specifications and
schedule under the proposed Requirement.

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b)

Requirement R2

R2. Each UVLS entity shall adhere to the UVLS Program
specifications and implementation schedule determined by its
Planning Coordinator or Transmission Planner associated with
UVLS Program development per Requirement R1 or with any
Corrective Action Plans per Requirement R5. [Violation Risk
Factor: High] [Time Horizon: Long‐term Planning]
Proposed Requirement R2 requires UVLS entities, as defined in the Applicability section
of PRC-010-1, to meet the specifications and implementation schedule provided by the Planning
Coordinator or Transmission Planner for a UVLS Program (designed under R1) or address any
necessary corrective actions for a UVLS Program (developed under R2). If UVLS entities do
not implement the UVLS Program according to the specifications and schedule provided, the
UVLS Program may not be effective and may not achieve its intended goal.
c)

Requirement R3

R3. Each Planning Coordinator or Transmission Planner shall
perform a comprehensive assessment to evaluate the effectiveness
of each of its UVLS Programs at least once every 60 calendar
months. Each assessment shall include, but is not limited to,
studies and analyses that evaluate whether: [Violation Risk
Factor: Medium] [Time Horizon: Long‐term Planning]
3.1. The UVLS Program resolves the identified
undervoltage issues for which the UVLS Program is
designed.
3.2. The UVLS Program is integrated through coordination
with generator voltage ride‐through capabilities and other
protection and control systems, including, but not limited
to, transmission line protection, autoreclosing, Remedial
Action Schemes, and other undervoltage‐based load
shedding programs.
In addition to the initial studies required to develop a UVLS Program, periodic
comprehensive assessments are required for continued effectiveness of the UVLS Program.
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Proposed Requirement R3 requires this type of assessment to be completed at least once every
sixty (60) calendar months to capture the cumulative effects of minor changes to the system that
have occurred since the last assessment was completed. This comprehensive assessment
supplements the annual assessment to evaluate the impact of Protection Systems required under
Reliability Standard TPL‐001‐4. The 60‐month period is the same time frame used for
assessments in TPL‐001‐4 and also in the PRC‐006‐1 assessment related to underfrequency load
shedding. The UVLS Program assessment must include studies and analysis that evaluate the
program based on two criteria, as described in subparts R3.1 and R3.2. These metrics are the
same two criteria used in the assessment under Requirement R1.
While not included in Requirement R3, at any point in time, a Planning Coordinator or
Transmission Planner may determine that a material change to system topology or operating
conditions affects the performance of the UVLS Program and, therefore, necessitates the same
comprehensive assessment. If a Planning Coordinator or Transmission Planner conducts a
comprehensive assessment sooner for the reasons discussed above, the 60‐month time period
would restart upon completion of this assessment.
d)

Requirement R4

R4. Each Planning Coordinator or Transmission Planner shall,
within 12 calendar months of an event that resulted in a voltage
excursion for which its UVLS Program was designed to operate,
perform an assessment to evaluate whether its UVLS Program
resolved the undervoltage issues associated with the event.
[Violation Risk Factor: Medium] [Time Horizon: Operations
Planning]
When a UVLS Program does not function as expected and designed during a voltage
excursion event, this presents a risk to system reliability. To mitigate this risk, proposed
Requirement R4 requires applicable entities to commence a timely assessment to evaluate
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whether the UVLS Program resolved the undervoltage issues associated with the applicable
event. This assessment must be completed within twelve calendar months from the date of the
event, as this timeframe provides the requisite time to coordinate with other Planning
Coordinators, Transmission Operators, Transmission Planners and UVLS entities to complete
the performance assessment.
e)

Requirement R5

R5. Each Planning Coordinator or Transmission Planner that
identifies deficiencies in its UVLS Program during an assessment
performed in either Requirement R3 or R4 shall develop a
Corrective Action Plan to address the deficiencies and
subsequently provide the Corrective Action Plan, including an
implementation schedule, to UVLS entities within three calendar
months of completing the assessment. [Violation Risk Factor:
Medium] [Time Horizon: Operations Planning]
If program deficiencies are identified during an assessment of a UVLS Program
performed in either Requirement R3 or R4, the Planning Coordinator or Transmission Planner
must develop a Corrective Action Plan to address the deficiencies.
The proposed Requirement sets a time period of three calendar months to provide the
Corrective Action Plan to UVLS entities. Based on the drafting team’s knowledge and
experience with UVLS studies, three calendar months was determined to provide a judicious
balance between the reliability need to address deficiencies expeditiously and the time needed to
consider potential solutions, coordinate resources, develop a Corrective Action Plan and
implementation schedule, and provide the Corrective Action Plan and schedule to UVLS entities.
The three‐month time frame is only to develop the Corrective Action Plan and provide it to
UVLS entities and does not encompass the time UVLS entities have to implement the Corrective

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Action Plan. Proposed Requirement R2 requires UVLS entities to execute the Corrective Action
Plan according to the schedule provided by the Planning Coordinator or Transmission Planner.
f)

Requirement R6, R7, and R8

R6. Each Planning Coordinator that has a UVLS Program in its
area shall update a database containing data necessary to model
the UVLS Program(s) in its area for use in event analyses and
assessments of the UVLS Program at least once each calendar
year. [Violation Risk Factor: Lower] [Time Horizon: Operations
Planning]
R7. Each UVLS entity shall provide data to its Planning
Coordinator according to the format and schedule specified by the
Planning Coordinator to support maintenance of a UVLS Program
database. [Violation Risk Factor: Lower] [Time Horizon:
Operations Planning]
R8. Each Planning Coordinator that has a UVLS Program in its
area shall provide its UVLS Program database to other Planning
Coordinators and Transmission Planners within its
Interconnection, and other functional entities with a reliability
need, within 30 calendar days of a written request. [Violation Risk
Factor: Lower] [Time Horizon: Operations Planning]
Having accurate and current data is required for the Planning Coordinator to perform
undervoltage studies and for use in event analyses. Proposed Requirement R6 supports this
reliability need by requiring the Planning Coordinator to update its UVLS Program database at
least once each calendar year. Proposed Requirement R7 requires the UVLS entity to provide
UVLS Program data in accordance with specified parameters. Proposed Requirement R8
requires that UVLS Program data be shared with neighboring Planning Coordinators and
Transmission Planners within a reasonable time period. Requests for the database must also be
fulfilled for those functional entities that have a reliability need for the data.
A UVLS Program database may include, but is not limited to, the following:
•

Owner and operator of the UVLS Program
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•

Size and location of customer load, or percent of connected load, to be interrupted

•

Corresponding voltage set points and clearing times

•

Time delay from initiation to trip signal

•

Breaker operating times

•

Any other schemes that are part of or impact the UVLS Programs, such as related
generation protection, islanding schemes, automatic load restoration schemes,
UFLS, and Remedial Action Schemes.

B.

Misoperation of UVLS Equipment

During the development of PRC-004-3 (Project 2010-05.1) and PRC-010-1 (Project
2008-02), both standard drafting teams decided that the UVLS standard drafting team would
address the Misoperation of UVLS equipment stemming from the retirement of PRC-022-1
(Under-Voltage Load Shedding Program Performance). The PRC-022-1 Reliability Standard
addressed Misoperation of UVLS; however, it was retired with the creation of PRC-010-1, which
was adopted by the Board on November 13, 2014. This aspect of PRC-022-1 will be accounted
for through further development work in Project 2008-02.2 Phase 2 Undervoltage Load
Shedding (UVLS): Misoperations.38 This phase of the UVLS project will address Misoperation
of UVLS equipment to complete the work anticipated by the two standard drafting teams. The
standard drafting team is currently working to make the necessary standard changes and
anticipates submitting proposed changes to Board in May for adoption pending favorable ballot
results.

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The Project webpage is available at http://www.nerc.com/pa/Stand/Pages/Project-2008-02_2-Phase-2Undervoltage-Load-Shedding-UVLS-Misoperations.aspx.

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C.

Enforceability of Proposed Reliability Standard

The proposed Reliability Standard PRC-010-1 includes Measures that support each
Requirement to help ensure that the Requirements will be enforced in a clear, consistent, nonpreferential manner and without prejudice to any party. The proposed Reliability Standard also
includes VRFs and VSLs for each Requirement. The VRFs and VSLs for the proposed
Reliability Standard comport with NERC and Commission guidelines related to their assignment.
A detailed analysis of the assignment of VRFs and the VSLs for proposed PRC-010-1is included
as Exhibit E.
VII.

Conclusion

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

•

the proposed Reliability Standard and other associated elements included in Exhibit A;

•

the new defined term, as noted herein;

•

the VRFs and VSLs (Exhibits A and E); and

•

the Implementation Plan, including the noted retirements, included in Exhibit B.

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Respectfully submitted,
/s/ William H. Edwards
Charles A. Berardesco
Senior Vice President and General Counsel
Holly A. Hawkins
Associate General Counsel
William H. Edwards
Counsel
North American Electric Reliability
Corporation
1325 G Street, N.W., Suite 600
Washington, D.C. 20005
(202) 400-3000
(202) 644-8099 – facsimile
[email protected]
[email protected]
[email protected]

Counsel for the North American Electric
Reliability Corporation
Date: February 6, 2015

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