Download WECC-0113 Posting 1 FAC-011-2 SOL Method for the Ops Horizon

White Paper
Retirement of WECC Regional Difference
FAC-011-2 System Operating Limits Methodology for the
Operations Horizon
155 North 400 West, Suite 200
Salt Lake City, Utah 84103-1114
WECC-0113 FAC-011-2 Variance Request to Retire
Executive Summary
The WECC-0113 Drafting Team (DT) makes the following recommendation regarding the retirement of
the FAC-011-2, System Operating Limits Methodology for the Operating Horizon (FAC), Regional
Difference (RD).
Recommendation
The WECC-0113 Drafting Team is recommending complete retirement of the RD subject to the
following caveat. Because the loss of Sections 1.3, 1.1.5, and 1.1.6 could impact the WECC Path Rating
process, the DT is recommending the substance of these sections be moved into the WECC Path Rating
process, or into a peripheral supporting document.
Analysis
After analysis of the FAC RD1, the WECC Reliability Subcommittee (RS) acting in its role as a
subcommittee of the WECC Planning Coordination Committee (PCC) concluded that the FAC RD should
be retired in its entirety as its content is outdated and/or redundant to existing NERC Standards.
The DT concurs with the RS analysis except in regards to Sections 1.3, 1.1.5, and 1.1.6. The drafting
team is concerned that retirement of the FAC RD will change the implementation of the WECC Path
Rating process thereby creating one rating system for existing paths and another for new paths.2 As
new paths are rated using new criteria it could affect the rating of existing paths as well; albeit, a
primary goal of the rating process is to protect existing path ratings.3 Further, the drafting team is
concerned that retirement of Sections E.1.3, 1.1.5 and 1.1.6 will delete requirements to examine
specific criteria beneficial to the rating process. As such, the recommendation is to retire the entire RD
except for Sections 1.3, 1.1.5, and 1.1.6; then, move the substance of those three sections either into
the WECC Path Rating process or other supporting documentation.
Both of the FAC for the operating horizon and FAC-010-2.1, System Operating Limits Methodology for
the Planning Horizon, contain identical RDs even though they are two very difference standards
1
For purposes of this document, the term variance is synonymous with regional difference.
“4. Path Rating Process: The purpose of the Path Rating Process is to provide a formal process for project sponsors to
attain an -Accepted Rating and demonstrate how their Project will meet NERC Reliability Standards and WECC Criteria. This
three-phase process addresses planned new facility additions and upgrades, or the re-rating of existing facilities. It requires
coordination through a review group comprised of the project sponsors and representatives of other systems that may be
affected by the project. Section 1.2 of the Path Rating Process explains which projects must undergo the three-phase rating
process.” WECC Project Coordination, Path Rating and Progress report Processes, Section 4, Path Rating Process. Adopted
by the Planning Coordinating Committee on July 15, 2014. See also Process, Policies, 2.2.2.
2
3
A primary objective of the Process is to: “2. Balance the competing interests of protecting the Accepted and Existing
Ratings of existing Paths.” Process, 2.1 Objectives, page 28. It should also be noted that the Process includes a means for
dispute resolution.
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WECC-0113 FAC-011-2 Variance Request to Retire
applicable in two different time horizons. The purpose of this recommendation is to provide
background and justification for retirement of the FAC RD subject to the proposed preceding condition.
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WECC-0113 FAC-011-2 Variance Request to Retire
Introduction
On April 10, 2003, WECC merged its transmission planning standards with that of the North American
Electricity Reliability Corporation (NERC4) creating a single document titled NERC/WECC Planning
Standards (PS). Noting that in some circumstances WECC’s criteria were more stringent than that of
NERC, WECC adopted the approach that “the more restrictive reliability criteria and guides must be
observed.”5
In April 2005, WECC moved its transmission planning criteria into the WECC Reliability Criteria, Part 1,
as approved in April 2005.
In November 2006, the NERC Board of Trustees approved FAC-011-1, System Operating Limit
Methodology for the Operations Horizon that included a WECC Regional Difference (RD) reflecting
WECC’s more stringent planning criteria in effect at the time.
In June 2008, the Federal Energy Regulatory Commission (FERC) approved version two of the FAC with
an Effective Date of July 1, 2008.6
In the 7 years since the approval of the FAC, WECC Reliability Coordinator’s System Operating Limit
(SOL) methodology has continued to evolve. In addition to this evolution, under the NERC Project
2015-03, NERC is currently reviewing a suite of FAC-related standards that includes the FAC.7 In NERC’s
first posting for industry comment, the team has pointed out that these standards presume operation
paradigms which are no longer valid in today’s environment.
Some highlights from the NERC review include:
•
FAC-011-3 and FAC-014-2 presume operations paradigms such as:


4
5
Perform study ahead of time to establish an SOL that achieves acceptable BulkElectric System (BES) performance per FAC-011-3, Requirement R2 and its
subparts
Communicate and coordinate SOLs with operators and other impacted entities
prior to implementation
In 2005 this was the North American Electricity Reliability Council.
WECC NERC/WECC Planning Standards, Page 4, April 10, 2003.
6
This standard contains a WECC RD identical to that of FAC-010-1, System Operating Limits Methodology for the Planning
Horizon.
7
Among those NERC Standards under review are: 1) FAC-010-2.1, System Operating Limits Methodology for the Planning
Horizon, 2) FAC-011-2, System Operating Limits for the Operations Horizon, and 3) FAC-014-2, Establish and Communicate
System Operating Limits.
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WECC-0113 FAC-011-2 Variance Request to Retire



•
Operation below the SOL with the presumption that doing so will result in
acceptable pre- and post-contingency system performance in real-time
Many entities establish SOLs and determine acceptable system performance in
real-time.
These standards should not presume operations paradigms, and should allow
entities more flexibility in determining how to achieve the ultimate reliability
objective of maintaining pre-and-post-contingency acceptable system
performance in real-time.
There is much confusion with, and many widely varied interpretations and applications of, the
term System Operating Limit (SOL)

Project 2014-03 developed a white paper to promote clarity, consistency, and a
common understanding of the concepts associated with establishing SOLs,
exceeding SOLs, and implementing Operating Plans to prevent and mitigate SOL
exceedance. That white paper served as a context for the new TOP/IRO
standards. A revised definition of SOLs and a new defined term SOL Exceedance
are proposed to improve clarity and alignment with proposed TOP and IRO
standards.
The FAC RD covering the planning horizon was copied directly from FAC-010-1, System Operating
Limits Methodology for the Operations Horizon. As a result, much of the FAC RD does not apply to the
operating horizon and has not been supported by any known technical analysis.
The language of the impacted NERC Standard and the associated regional difference is included in
Attachment A.
An implementation plan for complete retirement of the RD is included in Attachment B.
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WECC-0113 FAC-011-2 Variance Request to Retire
FAC-011-2 Analysis for Retirement
The purpose of the NERC Standard FAC-011-2 is to establish and document a methodology for use in
developing System Operating Limits (SOL) in the Operations Horizon. The FAC RD applies to
Requirements R3.3 that follows:
R3. The Reliability Coordinator’s methodology for determining SOLs, shall include, as a minimum, a
description of the following, along with any reliability margins applied for each:
R3.3. A process for determining which of the stability limits associated with the list of multiple
contingencies (provided by the Planning Authority in accordance with FAC-014
Requirement 6) are applicable for use in the operating horizon given the actual or
expected system conditions.
R3.3.1. This process shall address the need to modify these limits, to modify the list of
limits, and to modify the list of associated multiple contingencies.
Although the intent of the FAC RD is to specify multiple facility contingencies that apply to the Western
Interconnection, NERC Requirement R3.3 states the list of multiple contingencies is provided by the
Planning Authority in accordance with FAC-014-2, Establish and Communicate System Operating Limits,
Requirement R6 as follows:
R6. The Planning Authority shall identify the subset of multiple contingencies (if any), from Reliability
Standard TPL-003 which results in stability limits.
R6.1. The Planning Authority shall provide this list of multiple contingencies and the associated
stability limits to the Reliability Coordinators that monitor the facilities associated with
these contingencies and limits.
R6.2. If the Planning Authority does not identify any stability-related multiple contingencies, the
Planning Authority shall so notify the Reliability Coordinator.
Since the list of multiple contingencies is provided by the Planning Authority, and the contingencies are
identified in TPL-003 in accordance with FAC-014-2, the Reliability Subcommittee (RS) concludes that
the requirements contained in the FAC RD are irrelevant and should therefore be retired.
In FAC RD Section E., Subsection 1.1, the FAC RD includes seven criteria in conjunction with FAC-011-2,
Requirement R3.3. A great deal of confusion exists in applying these RDs to Requirement R3.3.
Requirement R3.3 addresses a process for determining multiple contingencies to establish SOL’s. Thus,
the intent of FAC RD and how it is to be applied remain unclear.
Each of the requirements in the FAC RD can be further examined to show that it: 1) is confusing and
difficult to apply, 2) is already covered by other NERC standards, and/or 3) does not have any reliability
value because it does not help in development of RC’s SOL methodology.
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WECC-0113 FAC-011-2 Variance Request to Retire
Sub Section 1.1
In FAC RD Section E., Subsection 1.1, the FAC RD includes seven criteria in conjunction with FAC-011-2,
Requirement R3.3.
FAC RD 1.1.1 states:
“1.1.1 Simultaneous permanent phase to ground Faults on different phases of each of two
adjacent transmission circuits on a multiple circuit tower, with Normal Clearing. If multiple
circuit towers are used for only station entrance and exist purposes, and if that do not exceed
five towers at each station, then this condition is an acceptable risk and therefore can be
excluded.”
Analysis
The language included in 1.1.1 requiring a mandate to address multiple circuit towers is redundant to
requirements in other NERC standards. Further, there is no justification for the requirement.
The underlying Requirement R2 incorporates by reference TPL-0038 that is due to be replaced by TPL001-4, Transmission System Planning Performance Requirements, on December 31, 2015. TPL-001-4
requires that the Transmission Planner and Planning Coordinator maintain planning models that
contain certain specifications, many of which are included in Table 1 of that document. Among the
modeling criteria specified in Table 1 is Category P7, Multiple Contingency, addressing “the loss of: 1)
Any two adjacent (vertically or horizontally) circuits on common structure, 2) Loss of a bipolar DC line.”
Because the FAC RD is addressed in other NERC standards, it should be deleted from FAC-011-2 as it
adds no additional reliability margin but does create the potential for double jeopardy.
In addition to this redundancy, the common stability programs in use today are based upon positive
sequence modeling and do not have the ability to simulate a simultaneous ground fault on different
phases of two different circuits. Further, no reliability benefit is obtained by simulating a single phaseto-ground fault on two different phases of two transmission circuits nor was the RS able to find where
any technical study on the matter was ever performed.
Recommendation
Whereas the language of 1.1.1 is redundant to other NERC standards, creates the potential for double
jeopardy, and adds no reliability margin, the entirety of the language should be retired.
8
TPL-003-0b, System Performance Following Loss of Two or More Bulk Electric System Elements (Category C) becomes
inactive on December 31, 2015.
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WECC-0113 FAC-011-2 Variance Request to Retire
FAC RD 1.1.2 states:
“1.1.2 A permanent phase to ground Fault on any generator, transmission circuit, transformer,
or bus section with Delayed Fault Clearing except for bus sectionalizing breakers or bus-tie
breakers addressed in E1.1.7”
Analysis
This requirement is addressed in NERC Standard TPL-001-4, Table 1, Category P4 and P5 contingencies.
Recommendation
Whereas the language of 1.1.2 is redundant to other NERC Standards and creates the potential for
double jeopardy, the entirety of the language should be retired.
FAC RD 1.1.3 states:
“1.1.3 Simultaneous permanent loss of both poles of a direct current bipolar Facility without
an alternating current Fault.”
Analysis
This requirement is address in the NERC Standard TPL-001-4, Table 1, Category P7 contingency.
Recommendation
Whereas the language of 1.1.3 is redundant to other NERC Standards and creates the potential for
double jeopardy, the entirety of the language should be retired.
FAC RD 1.1.4 states:
“1.1.4 The failure of a circuit breaker associated with a Special Protection System to operate
when required following: the loss of any element without a Fault; or a permanent phase to
ground Fault, with Normal Clearing, on any transmission circuit, transformer or bus section.”
Analysis
Developed as WECC-0113
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WECC-0113 FAC-011-2 Variance Request to Retire
This requirement is addressed in NERC Reliability Standard PRC-012-09, Special Protection System
Review Procedure, Requirement R1.3.:
“R1.3. Requirements to demonstrate that the RAS shall be designed so that a single RAS
component failure, when the RAS was intended to operate, does not prevent the
interconnected transmission system from meeting the performance requirements defined in
Reliability Standards TPL-001-0, TPL-002-0, and TPL-003-0.”
The PRC-012-0 Requirement requires that failure of a single component does not prevent the
interconnected system from meeting required performance in the TPL-related standards. This
reliability concern is also addressed in NERC Standard TPL-001-4, Table 1, Category P4 and P5, which
specifies system performance requirements for stuck breaker and protection system failure.
Recommendation
Whereas the language of 1.1.4 is redundant to other NERC Standards and creates the potential for
double jeopardy, the entirety of the language should be retired.
FAC RD 1.1.5 states:
“1.1.5 A non-three phase Fault with Normal Clearing on common mode Contingency of two
adjacent circuits on separate towers unless the event frequency is determined to be less than
one in thirty years.”
Analysis
Requirement E1.1.5 extends the requirement of NERC Reliability Standard TPL-001-4, Table 1, Category
P7 contingency to “two adjacent circuits” on separate structures. Within the NERC TPL-004-0a and on
adoption of TPL-001-4 this contingency is considered an extreme event as indicated below in TPL-001-4
Requirements 3.5 and 4.5 incorporating Table 1 – Steady State & Stability Performance Extreme Events
as follows:
 Steady state item 2.b
2. Local area events affecting the Transmission System such as:
a. Loss of a tower line with three or more circuits.
b. Loss of all Transmission lines on a common Right-of-Way.
c. Loss of a switching station or substation (loss of one voltage level plus transformers).
d. Loss of all generating units at a generating station.
e. Loss of a large Load or major Load center.
9
Although this is a Version Zero document its successor Version 1 is pending regulatory filing and Requirement R1.3 is
virtually unchanged with the exception of a definition change from Special Protection System to Remedial Action Scheme.
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WECC-0113 FAC-011-2 Variance Request to Retire
 Stability item 1
1. With an initial condition of a single generator, Transmission circuit, single pole of a DC line,
shunt device, or transformer forced out of service, apply a 3Ø fault on another single
generator, Transmission circuit, single pole of a different DC line, shunt device, or
transformer prior to System adjustments.
In 2003, when the FAC RD was written there was no action required in the NERC Standards for multiple
contingencies in the same rights-of-way. Within TPL-001-4, Transmission Planners are now required to
conduct simulations of multiple circuit outages in the same rights-of-way as an extreme event and if
the analysis concludes there is Cascading caused by the occurrence of extreme events, an evaluation of
possible actions designed to reduce the likelihood or mitigate the consequences and adverse impacts
of the event(s) shall be conducted. While the extreme event assessment is to evaluate possible
actions, it does not require a corrective action plan. Thus for a contingency of two adjacent circuits on
separate towers , TPL-001-4 does not require a corrective action plan, whereas FAC-010-2.1
Requirement E.1.1.5 does require the same performance as a P-7 contingency if the event frequency is
greater than one in 30 years.
In addition, Requirement E1.1.5 uses the term “adjacent circuits” but the term is not defined in the
NERC Glossary of Terms Used in Reliability Standards (NERC Glossary). This lack of definition in the
NERC Glossary creates ambiguity in the implementation of the RD.10 Although WECC has made efforts
to clarify the ambiguity through approval of a WECC Regional Criterion TPL-001-WECC-CRT-2, System
Performance Criterion (CRT) 11 and the associated definition of Adjacent Transmission Circuits12
10
Although the term is defined in the WECC Glossary of Terms and Naming Conventions, the term is slated for retirement
under WECC Standards Authorization WECC-0100, TPL-001-WECC-CRT-3, System Performance as the term will no longer be
used in a WECC Regional Criterion.
11
“Regional Criteria” means reliability requirements developed by a Regional Entity that are necessary to implement, to
augment, or to comply with Reliability Standards, but which are not Reliability Standards. Such Regional Criteria may be
necessary to account for physical differences in the Bulk Power System but are not inconsistent with Reliability Standards
nor do they result in lesser reliability. Such Regional Criteria are not enforceable pursuant to NERC-delegated authorities,
but may be enforced through other available mechanisms. Regional Criteria may include specific acceptable operating or
planning parameters, guides, agreements, protocols or other documents.” NERC Rules of Procedure, Definitions.
There are conflicts and ambiguities between FAC-010-2.1 and the WECC Regional Criterion TPL-001-WECC-CRT-2.1.
Regional Difference Requirement E.1.1.5 of the current standard FAC-010-2.1 only applies to adjacent circuits that are Bulk
Electric System (BES) elements, is not restricted by voltage levels, and does not exclude circuits that share a common rightof-way. Whereas, TPL-001-WECC-CRT-2.1 Regional Criterion excludes circuits on common right-of-way for less than 3 miles
and circuits less than 300 kV.
12
“Adjacent Transmission Circuits are two transmission circuits with separation between their center lines less
than 250 feet at the point of separation with no Bulk Electric System circuit between them.
Transmission circuits that cross, but are otherwise separated by 250 feet or more between their centerlines, are
not Adjacent Transmission Circuits.” WECC Glossary for Terms Developed Using the WECC Reliability Standards
Development Procedures
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WECC-0113 FAC-011-2 Variance Request to Retire
because the CRT only augments the standard, the CRT is not the definitive authority on how the
standard must be implemented. As such the ambiguity would be eliminated if the language was
deleted.13
Finally, at the time the FAC RD was developed, it was believed that the rate of common mode outages
of adjacent circuits on separate structures was similar to that of any two circuits of a multiple circuit
tower line (covered by Category P7). As such, it made sense to apply the same performance criteria to
both classes of contingencies. However, actual performance data for 230kV and above transmission
lines in the Western Interconnection indicate that the average outage rate per 100 miles of line is
actually less than one-half the rate for circuits on common structures as shown in the table below.
The actual outage rate for circuits on common rights-of-way but on separate structures is also less than
that for any two circuits not on a common right-of-way. The reason for these statistical differences is
the configuration of the substation. Adjacent circuits are typically connected into separate bays of a
substation, which reduces the common mode outages of breaker or protection system failures.
Therefore, Requirement E1.1.5 can be deleted without adversely impacting the reliability of the Bulk
Electric System.
Table A
Outage Comparison of Circuits on Common ROW and/or Structures when 2 or more circuits went
out of service.
Circuits on
Western
Common RightInterconnection
Circuits on Common
Circuits not on Common ROW
of-Way
Average Data
Structure
or Structure
Separate
2008-2012
Structures
Transmission Miles
8,822
14,782
51,649
24
22
103
Number of Events
13
In WECC Regional Criterion TPL-001-WECC-CRT-2, System Performance Criterion (CRT), the adjacent circuit application is
limited to the following:



Applies to circuits 300 kV and higher.
Does not apply to Adjacent Transmission Circuits that share a common right-of-way for a total of three miles or
less, including – but not limited to – substation entrances, pinch points, and river crossings.
Applies only to effects on facilities external to a Transmission Planner area.
Thus, FAC-010 regional differences create confusion and ambiguity.
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Table A
Outage Comparison of Circuits on Common ROW and/or Structures when 2 or more circuits went
out of service.
Circuits on
Western
Common RightInterconnection
Circuits on Common
Circuits not on Common ROW
of-Way
Average Data
Structure
or Structure
Separate
2008-2012
Structures
No. of Outages/ 100
miles of line
0.271
0.147
0.207
The above table is based upon six years of historical data collected by WECC. WECC began collecting
right-of-way outage data in 2008.14
WECC Path Ratings for a number of major paths within the Western Interconnection have been
established applying the performance requirements of Requirement E1.1.5. If the performance
requirements of TPL-001-4 with the contingency being considered an extreme event is applied, as
opposed to the contingency being treated as a P7 contingency as per Requirement E1.1.5, it will result
in potential for changes in path ratings for these paths.
Currently the WECC Path Rating process requires extreme events (Category D) to be assessed but does
not require mitigation in establishing path ratings. If the language s retired, it could result in new path
ratings under one set of criteria juxtaposed to existing path ratings created under a different and preexisting set of criteria.
This performance requirement change leads to a process issue affecting path ratings and the
associated allocations.
Recommendation
Whereas the loss of Section 1.1.5 could impact the WECC Path Rating process, the DT is recommending
the substance of this section migrate into the WECC Path Rating process, or into a peripheral
supporting document.
FAC RD 1.1.6 states:
“1.1.6 A common mode outage of two generating units connected to the same switchyard, not
otherwise addressed by FAC-010.”
14
The drafting team understands that the table contains a statistically small sampling for evaluating a one-in-30 year event.
As such, the drafting team encourages the industry to draw its own conclusions based on the available data.
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Analysis
Requirement E1.1.6 requires that a common mode outage of two generating units connected to the
same switchyard demonstrate transient, dynamic, and voltage stability and does not allow for
cascading. Within the NERC TPL-004-0a and on adoption of TPL-001-4 this contingency is considered
an extreme event as indicated below in TPL-001-4 Requirements 3.5 and 4.5 incorporating Table 1 –
Steady State & Stability Performance Extreme Events as follows:
 Steady-state Item 1
1. Loss of a single generator, Transmission Circuit, single pole of a DC Line, shunt device, or
transformer forced out of service followed by another single generator, Transmission
Circuit, single pole of a different DC Line, shunt device, or transformer forced out of service
prior to System adjustments.
 Steady-state Item 2.d
2. Local area events affecting the Transmission System such as:
a. Loss of a tower line with three or more circuits.
b. Loss of all Transmission lines on a common Right-of-Way.
c. Loss of a switching station or substation (loss of one voltage level plus transformers).
d. Loss of all generating units at a generating station.
e. Loss of a large Load or major Load center.
 Stability Item 1
1. With an initial condition of a single generator, Transmission circuit, single pole of a DC line,
shunt device, or transformer forced out of service, apply a 3Ø fault on another single
generator, Transmission circuit, single pole of a different DC line, shunt device, or
transformer prior to System adjustments.
In 2003 when the FAC RD was written, there was no action required in the NERC Standards for loss of
two generating units at a generating station resulting from contingencies beyond those specified in
Table 1. Within TPL-001-4, Transmission Planners are now required to conduct simulations of
simultaneous loss of multiple generators as an extreme event; and, if the analysis concludes there is
Cascading caused by the occurrence of extreme events, an evaluation of possible actions designed to
reduce the likelihood or mitigate the consequences and adverse impacts of the event(s) shall be
conducted. While the extreme event assessment is to evaluate possible actions, it does not require a
corrective action plan for cascading. Thus, if a common mode contingency of two generating-units
results in cascading, TPL-001-4 does not require a corrective action plan, whereas FAC-010-2.1
Requirement E.1.1.6 does require a corrective action plan (establishment of an SOL in this context).
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WECC Path Ratings for a number of major paths within the Western Interconnection have been
established applying the performance requirements of Requirement E1.1.6. If the performance
requirements of TPL-001-4 with the contingency being considered an extreme event is applied, as
opposed to requiring mitigation for cascading as per Requirement E1.1.6, it will result in potential
changes in path ratings for these paths.
Currently the WECC Path Rating process requires extreme events (Category D) to be assessed but does
not require mitigation in establishing path ratings. If the language is retired, it could result in new path
ratings under one set of criteria juxtaposed to existing path ratings created under a different and preexisting set of criteria. Among others, this raises the question as to whether the existing paths should
be re-rated using a different set of criteria. The drafting team does not posit an answer; it merely
highlights the issue.
Currently the WECC Path Rating process requires extreme events (Category D) to be assessed but does
not require mitigation in establishing path ratings. If the language is retired, it could result in new path
ratings under one set of criteria juxtaposed to existing path ratings created under a different and preexisting set of criteria. Among others, this raises the question as to whether the existing paths should
be re-rated using a different set of criteria. The drafting team does not posit an answer; it merely
highlights the issue.
Recommendation
Whereas the loss of Section 1.1.6 could impact the WECC Path Rating process, the DT is recommending
the substance of this section migrate into the WECC Path Rating process, or into a peripheral
supporting document.
FAC RD 1.1.7 states:
“1.1.7 The loss of multiple bus sections as a result of failure or delayed clearing of a bus tie or
bus sectionalizing breaker to clear a permanent Phase to Ground Fault.”
Analysis
This requirement is addressed in NERC Reliability Standard TPL-001-4, Table 1, Categories P4 and P5.
Having a regional difference duplicating the TPL-001-4 Reliability Standard is redundant and
unnecessary.
Recommendation
Whereas the language of 1.1.7 is redundant to other NERC Standards and creates the potential for
double jeopardy, the entirety of the language should be retired.
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Sub Section 1.2
In Section E. Regional Differences, Subsection 1.2, the FAC RD requires that SOLs be “established such
that for multiple Facility Contingencies in E1.1.1 through E1.1.5 operation within the SOL shall provide
system performance consistent with seven specific performance requirements.
Recommendation
Each of the seven specific requirements within FAC RD Sub Section 1.2 is duplicated in the FAC-010-2.1
Requirements R2.5 and R2.6. As such the entire section should be retired because it is redundant to
underlying standard’s Requirements R2.5 and R2.6.
Table B
NERC Standard / FAC RD Cross-reference Table
NERC Standard Requirement from FACFAC RD
011-2
Requirement 2.5
R2.5 Starting with all Facilities in service
and following any of the multiple
Contingencies identified in Reliability
Standard TPL-003 the system shall
demonstrate:
R2.5 Transient, dynamic and voltage
stability voltage and stability limits
R2.5 All Facilities shall be operating within
their Facility Ratings and within their
thermal, voltage and stability limits
R2.5 Cascading or uncontrolled separation
shall not occur.
1.2. SOLs shall be established such that for
multiple Facility Contingencies in E1.1.1
through E1.1.5 operation within the SOL
shall provide system performance
consistent with the following:
1.2.4 The system demonstrates transient,
dynamic and voltage stability.
1.2.1 All Facilities are operating within their
applicable Post-Contingency thermal,
frequency and voltage limits.
1.2.2
Cascading does not occur.
1.2.3
Uncontrolled separation of the
system does not occur.
Requirement R2.6
R2.6.1. In determining the system’s
response…the following shall be
acceptable:
1.2.5
R2.6.1. Planned or controlled interruption
of electric supply to customers (load
shedding)
R2.6.1. The planned removal from service
1.2.5 The controlled interruption of electric
supply to customers (load shedding)
Developed as WECC-0113
Depending on system design and
expected system impacts [the following
may be necessary and are acceptable]
1.2.5 The planned removal from service of
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WECC-0113 FAC-011-2 Variance Request to Retire
of certain generators,
R2.6.1 The curtailment of contracted Firm
(non-recallable reserved) electric power
R2.3.2. System reconfiguration through
manual or automatic control or protection
actions.
R2.4. To prepare for the next Contingency,
system adjustments may be made,
including changes to generation, uses of the
transmission system, and the transmission
system topology.
certain generators
1.2.5
And/or the curtailment of
contracted firm (nonrecallable reserved)
electric power transfers may be necessary
to maintain the overall security of the
interconnected transmission systems.
1.2.6
Interruption of firm transfer, Load
or system reconfiguration is permitted
through manual or automatic control or
protection actions.
1.2.7
To prepare for the next
Contingency, system adjustments are
permitted, including changes to
generation, Load and the transmission
system topology when determining limits
Sub Section 1.3
FAC RD E.1.3 states:
“1.3
SOLs shall be established such that for multiple Facility Contingencies in E1.1.6 through
E1.1.7 operation within the SOL shall provide system performance consistent with the
following with respect to impacts on other systems:
1.3.1 Cascading does not occur.”
Analysis
Requirement E.1.3 establishes the performance requirement (no cascading) for Requirement E.1.1.6
and E.1.1.7 regarding establishment of SOLs. As identified in the analysis of Requirement E.1.1.6
above, there are issues associated with the retirement of the contingency identified in E.1.1.6 that
would be the same for the performance requirement identified in E.1.3.
Recommendation
Whereas the loss of Section 1.3 could impact the WECC Path Rating process, the DT is recommending
the substance of this section migrate into the WECC Path Rating process, or into a peripheral
supporting document.
Developed as WECC-0113
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WECC-0113 FAC-011-2 Variance Request to Retire
Sub Section 1.4
FAC RD E1.4 states:
“1.4.
The Western Interconnection may make changes (performance category adjustments)
to the Contingencies required to be studied and/or the required responses to
Contingencies for specific facilities based on actual system performance and robust
design. Such changes will apply in determining SOLs.”
Analysis
The FC RD applies to “the Western Interconnection” and is not applicable to any specific entity
identified in the NERC Reliability Functional Model. Further, the language is permissive using “may”
and not “shall”. Finally, the language does not add any system performance requirement in addition to
the existing requirements in NERC Reliability Standard TPL-0001-4.
Recommendation
Because the FAC RD Section 1.4 does not apply to a specified entity in the NERC Functional Model, and
whereas the language us permissive in nature, it cannot be enforced and should be retired.
Developed as WECC-0113
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WECC-0113 FAC-011-2 Variance Request to Retire
Attachment A
NERC FAC-011 Impacted Requirements and Regional Differences
The FAC-011-2 Standard has five Requirements. The associated WECC variance is associated with the
list of multiple contingencies provided by the Planning Authority in Requirement R3.3. This section
contains the complete text of Requirement R3, Sections 3.3 and 3.3.1 and the associated RD that is
recommended for retirement.
Requirement R3, Sections R3.3 and R3.3.1
R3. The Reliability Coordinator’s methodology for determining SOLs, shall include, as a minimum, a
description of the following, along with any reliability margins applied for each:
R3.3. A process for determining which of the stability limits associated with the list of multiple
contingencies (provided by the Planning Authority in accordance with FAC-014
Requirement 6) are applicable for use in the operating horizon given the actual or
expected system conditions.
R3.3.1. This process shall address the need to modify these limits, to modify the list of limits, and to
modify the list of associated multiple contingencies.
Regional Differences (The entirety of this section is proposed for retirement.)
E. Regional Differences
1. The following Interconnection-wide Regional Difference shall be applicable in the Western
Interconnection:
1.1
As governed by the requirements of R2.5 and R2.6, starting with all Facilities in service,
shall require the evaluation of the following multiple Facility Contingencies when
establishing SOLs:
1.1.1 Simultaneous permanent phase to ground Faults on different phases of each of
two adjacent transmission circuits on a multiple circuit tower, with Normal
Clearing. If multiple circuit towers are used for only station entrance and exist
purposes, and if that do not exceed five towers at each station, then this
condition is an acceptable risk and therefore can be excluded.
1.1.2 A permanent phase to ground Fault on any generator, transmission circuit,
transformer, or bus section with Delayed Fault Clearing except for bus
sectionalizing breakers or bus-tie breakers addressed in E1.1.7
Developed as WECC-0113
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WECC-0113 FAC-011-2 Variance Request to Retire
1.1.3 Simultaneous permanent loss of both poles of a direct current bipolar Facility
without an alternating current Fault.
1.1.4 The failure of a circuit breaker associated with a Special Protection System to
operate when required following: the loss of any element without a Fault; or a
permanent phase to ground Fault, with Normal Clearing, on any transmission
circuit, transformer or bus section.
1.1.5 A non-three phase Fault with Normal Clearing on common mode Contingency of
two adjacent circuits on separate towers unless the event frequency is
determined to be less than one in thirty years.
1.1.6 A common mode outage of two generating units connected to the same
switchyard, not otherwise addressed by FAC-010.
1.1.7 The loss of multiple bus sections as a result of failure or delayed clearing of a bus
tie or bus sectionalizing breaker to clear a permanent Phase to Ground Fault.
1.2.
SOLs shall be established such that for multiple Facility Contingencies in E1.1.1 through
E1.1.5 operation within the SOL shall provide system performance consistent with the
following:
1.2.1 All Facilities are operating within their applicable Post-Contingency thermal,
frequency and voltage limits.
1.2.2 Cascading does not occur.
1.2.3 Uncontrolled separation of the system does not occur.
1.2.4 The system demonstrates transient, dynamic and voltage stability.
1.2.5 Depending on system design and expected system impacts, the controlled
interruption of electric supply to customers (load shedding), the planned
removal from service of certain generators, and/or the curtailment of contracted
firm (nonrecallable reserved) electric power transfers may be necessary to
maintain the overall security of the interconnected transmission systems.
Developed as WECC-0113
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WECC-0113 FAC-011-2 Variance Request to Retire
1.2.6 Interruption of firm transfer, Load or system reconfiguration is permitted
through manual or automatic control or protection actions.
1.2.7 To prepare for the next Contingency, system adjustments are permitted,
including changes to generation, Load and the transmission system topology
when determining limits.
1.3.
SOLs shall be established such that for multiple Facility Contingencies in E1.1.6 through
E1.1.7 operation within the SOL shall provide system performance consistent with the
following with respect to impacts on other systems:
1.3.1 Cascading does not occur.
1.4.
The Western Interconnection may make changes (performance category adjustments)
to the Contingencies required to be studied and/or the required responses to
Contingencies for specific facilities based on actual system performance and robust
design. Such changes will apply in determining SOLs.
Developed as WECC-0113
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WECC-0113 FAC-011-2 Variance Request to Retire
Attachment B
Implementation Plan for Retirement of Regional Differences
FAC-011-2, System Operating Limits Methodology for the Operations Horizon
Approvals Required

WECC Ballot Pool

WECC Standards Committee

WECC Board of Directors

NERC Board of Trustees

Federal Energy Regulatory Commission and other jurisdictions
Applicable Entities
Planning Authority
Conforming Changes to Other Standards
None are required; however, the following Condition Precedent section should be considered.
Proposed Effective Date
The first day of the first quarter following regulatory approval
Justification
The entirety of the FAC RD should be retired because the reliability-related tasks are addressed
elsewhere. Full retirement is subject to the Condition Precedent section below,
Consideration of Early Compliance
Please see the Condition Precedent section that follows.
Required Retirements
The entire FAC RD specific to the Western Interconnection
Condition Precedent
Because the loss of Sections 1.3, 1.1.5, and 1.1.6 could impact the WECC Path Rating process, the DT is
recommending the substance of these sections be moved into the WECC Path Rating process, or into a
peripheral supporting document.
Developed as WECC-0113
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