Comment Report Form for WECC-01131

Posting #1

The WECC-0113, FAC-010/011 request to Retire Regional Variance Drafting Team (DT) thanks everyone who submitted comments on the proposed documents.

Posting

This document was last posted for a 45-day public comment period fromJuly 24 through September8,2015.

WECC distributed the notice for the posting onJuly 23, 2015.The DT asked stakeholders to provide feedback on the proposed document through a standardized electronic template. WECC received comments from one company representing three of the eight Industry Segments, as shown in the table on the following page.

Location of Comments

All comments received on the document can be viewed in their original formaton the project page under the “Submit and Review Comments” accordion.

Changes in Response to Comment

After consideration of the comment received, the drafting team made the following change regarding Section E. Regional Differences, sub-section 1.1.4 in both white papers:

After considering the comment, the drafting team reached the following conclusions.

  • All of the language of both Variances should be retired except forSection E. Regional Differences, subsections 1.1.4, 1.1.5, and 1.1.6 (residual language).
  • The residual language would remain as a Facilities Design, Connections and Maintenance (FAC) Variance in both FACs until relocated to a more suitable NERC Standard such as TPL-001-4 or PRC-012-0. This would lay the foundation for a two-step retirement of the two FAC Variances, subject to relocation of the language, while supporting any parallel NERC action to retire the FACs to which the Variances are appended.
  • The drafting team does not have the subject-matter expertise required to determine the best NERC Standard to which the residual language should be appended.
  • Proceeding on the premise that Posting 2 will not raise any further substantive issues, the drafting team would request that the WECC Standards Committee call for a ballot to retire the two Variances, sans the residual language.
  • An affirmative ballot would conclude the drafting team’s responsibilities and the project would be forwarded to WECC/NERC/FERC for disposition.
  • A separate SAR would be filed to precisely locate the residual language.The new SAR would be accompanied by solicitation of a new drafting team with the required skillset.

On September 17, 2015, after consideration of the comment received, the drafting team opted to repost the document for a 30-day comment period.The window was targeted to open September 18, 2015 and close on October 21, 2015.The drafting team reconvened on October 28, 2015 from 10:00 a.m. to 12:00 p.m. (Mountain) to address any new comments received.

Contacts and Appeals

If you feel your comment has been omitted or overlooked, please contact the Manager, WECC Standards Processes, W. Shannon Black, at . In addition, there is a WECC Reliability Standards Appeals Process.

The WECC Standards Voting Sectors are:

1 — Transmission Sector

2 — Generation Sector

3 — Marketers and Brokers Sector

4 — Distribution Sector

5 — System Coordination Sector

6 — End Use Representative Sector

7 — State and Provincial Representatives Sector

8 — Other Non-Registered WECC Members and Participating Stakeholders Sector

Commenter / Organization / WECC Standards Voting Sectors
1 / 2 / 3 / 4 / 5 / 6 / 7 / 8
1 / Gene Henneberg / NV Energy / X / X / X / X / X

Index to Questions, Comments, and Responses

Question

  1. The drafting team invites comments on all aspects of the proposed document.
  1. The drafting team invites comments on all aspects of the proposed document.

Summary Consideration: / See summary in the preamble of this document.
Commenter / Yes / No / Comment
NV Energy / Breaker failures associated with RAS were discussed at the July 7, 2015 Remedial Action Scheme Reliability Subcommittee meeting in Salt Lake City. Rikin Shah attended this RASRS discussion and has a copy of the Power Point slides used during that discussion. These comments expand on parts of that discussion.
The proposal to retire the FAC-010 and modify FAC-011 standards includes retirement of WECC variance E1.1.4 in both standards. This variance addresses failure of a RAS-associated circuit breaker to operate (trip or close) when the RAS calls for it to operate. The existing variance probably is misplaced in FAC-010 and perhaps shouldn’t have been in FAC-011 at all, because it really describes a Planning issue that would be more appropriately addressed during scheme design, rather than as an operating issue as a System Operating Limit (SOL).
The WECC FAC RD for FAC-010 only affects Requirement R2 (Parts 2.5 and 2.6) of the underlying FAC. Requirement R2 requires that each Planning Authority’s System Operating Limit (SOL) Methodology include a requirement that SOLs provide performance at a specified threshold. FAC-011 is similar, but applies to the Reliability Coordinator rather than the Planning Coordinator. FAC RD 1.1.4 then states:
1.1.4 The failure of a circuit breaker associated with a Special Protection System [RAS] 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.
The WECC Reliability Subcommittee issued a recent white paper several months ago saying that this variance isn’t needed because the problem is covered by PRC-012_R1.3 and by TPL-001-4 Table 1, P4 and P5. The present proposal by the WECC-0113 drafting team echoes these conclusions.
The WECC Reliability Subcommittee (RS) and WECC-0113 drafting team discussion is very short and does not address several critical and questionable assumptions that led to the stated conclusion. PRC-012 and TPL-001-4 standards actually cover less than what was claimed by the WECC Reliability Subcommittee white paper and the WECC-0113 drafting team. If this proposed retirement is accepted, unmodified RAS within WECC will be allowed to establish higher SOLs than presently acceptable with no system changes or (more likely) RAS could be designed to a lower standard of reliability.
PRC-012 R1.3 does talk about SPS [RAS] single component failure, but to be correct, the WECC RS and WECC-0113 drafting team discussion has to assume that the circuit breaker is a “RAS component." Only the potentially related NERC Glossary term Protection System describes what “components” might be included in a RAS,
• Protective relays which respond to electrical quantities,
• Communications systems necessary for correct operation of protective functions
• Voltage and current sensing devices providing inputs to protective relays,
• Station dc supply associated with protective functions (including station batteries, battery chargers, and non-battery-based dc supply), and
• Control circuitry associated with protective functions through the trip coil(s) of the circuit
breakers or other interrupting devices.
This Protection System “component” list was extended by PRC-005-3 to also include:
• Reclosing relay
• Control circuitry associated with the reclosing relay.
Then PRC-005-3 also added the following definition:
Component – A Component is any individual discrete piece of equipment included in a Protection System or in Automatic Reclosing, including but not limited to a protective relay, reclosing relay, or current sensing device. The designation of what constitutes a control circuit Component is dependent upon how an entity performs and tracks the testing of the control circuitry. Some entities test their control circuits on a breaker basis whereas others test their circuitry on a local zone of protection basis. Thus, entities are allowed the latitude to designate their own definitions of control circuit Components. . . . [followed by two examples]
The intent of the PRC-005-3 Component definition was to provide some latitude in identifying, or at least counting “components” for maintenance purposes, and only within the PRC-005 standard. The Component emphasis remains on control circuitry. However, there is not a whisper of a suggestion that the breaker operating mechanism, interrupter, or bushings are expected to be included as either a Protection System or RAS “Component.”
NERC is revising PRC-012. While I do not claim to speak for NERC or forecast the final result, as chair of that NERC standard drafting team, I believe I can interpret the direction that this standard drafting effort is heading. The first official “for comment and voting” posting is scheduled August 20. The SDT is proposing to keep the content of PRC-012-0_R1.3, with some minor wording changes. But the “RAS component” list would at most add only RAS controllers to the Protection System list--not circuit breakers. In fact, when I specifically raised the circuit breaker issue at the SDT, the rapid consensus was that a circuit breaker associated with a RAS is not a RAS component and should not be covered by the proposed new PRC-012 standard.
No other Region interprets a circuit breaker associated with a RAS as a RAS component subject to PRC-012-0_R1.3. Most Regions do not raise the issue at all. Only NPCC’s Directory 7 discusses failure of a breaker associated with an SPS [RAS] to operate for NPCC Type I schemes. NPCC treats these breakers, on the design level, similar to the way the WECC variance E1.1.4 does. However, Directory 7 is not part of a NERC-approved standard.
Since a “circuit breaker associated with a RAS” is not considered to be a “RAS component” by NERC or other Regions, then the existing PRC-012_R1.3 requirement does not address these circuit breakers. Subsequently, there is no potential for double jeopardy between this WECC variance E1.1.4 and PRC-012_R1.3 because the two requirements address operation of different equipment.
The WECC RS white paper and WECC-0113 drafting team also conclude that variance E1.1.4 is covered by TPL-001-4, Table 1, P4 and/or P5 contingencies. This conclusion at least implies that the failure of a RAS-associated breaker to operate is the next contingency within the context of Table 1, i.e. the breaker failure event turns a P1 or P2 single contingency into a P4 or P5 multiple contingency or a P3-P7 multiple contingency into an extreme event. This conclusion does not seem consistent with the wording and scope of Table 1.
Table 1 is pretty focused on clearing Faults. P4 addresses the case where a stuck breaker results in a multiple contingency because additional elements must trip to clear a SLG fault (Fault plus stuck breaker). P4 does not care why the breaker is stuck, but the purpose is Fault clearing. P5 addresses a multiple contingency resulting from delayed fault clearing due to a failed non-redundant relay (Fault plus relay failure to operate). A note lists specific applicable relay functions for P5, but, as with P4, the purpose is Fault clearing.
Special Protection Systems [RAS] are not intended to clear faults, as is illustrated in the original NERC SPS Glossary definition:
An automatic protection system designed to detect abnormal or predetermined system conditions, and take corrective actions other than and/or in addition to the isolation of faulted components to maintain system reliability. . . .
The proposed new NERC definition of Remedial Action Scheme, which FERC’s June 18, 2015 NOPR proposes to approve, includes:
The following do not individually constitute a RAS:
a. Protection Systems installed for the purpose of detecting Faults on BES Elements and isolating the faulted Elements . . . .
Whether using the original or proposed new NERC Glossary RAS definition, RAS are not intended to clear Faults. As should also be clear from the wording of E1.1.4, “a circuit breaker associated with a Special Protection System [RAS] to operate when required” addresses RAS operation, not clearing Faults.
With very limited exceptions, TPL-001-4, Table 1 addresses Fault clearing. The exceptions, and therefore potential applicability of Table 1 directly to RAS, are only P0 (No contingency) and P2 (1) Opening of any element without a Fault, which is one of the covered operations included in E1.1.4.
Table 1, P4 is the traditional case of a breaker “attempting to clear a [SLG] Fault” on an element and failing to do so, which then must be cleared by delayed, backup operation of other protection. The other protection is usually a breaker failure scheme that is initiated by the relay(s) that originally detected the Fault. When the breaker failure scheme operates, it trips the circuit breakers that are electrically adjacent to the failed breaker, thus interrupting all sources to the Faulted element. A breaker failure operation usually removes multiple Elements from service, in addition to the Faulted element.
A RAS may be designed to switch or otherwise affect operation of any of the identified Elements in P4, e.g. shunt capacitor switching. But such RAS operations are not intended for the purpose of clearing Faults, as noted above.
The breaker failure scheme may, but is not required to be initiated by a RAS operation. Whether breaker failure initiation is appropriate as part of a RAS operation needs to be separately studied. A breaker failure operation usually makes significant changes in the System configuration. The reconfiguration, by itself, may have a significant and potentially adverse impact on System performance, especially in conjunction with other Elements that are removed from service due to Fault clearing.
Table 1, P5 is the case where “Delayed [SLG] Fault Clearing due to the failure of a non-redundant [13] relay protecting the Faulted element to operate as designed . . .” for a specific element list. The specific non-redundant relay functions or types are identified in Note 13 as “. . . pilot (#85), distance (#21), differential (#87), current (#50, 51, and 67), voltage (#27 & 59), directional (#32, & 67), and tripping (#86, & 94).”
A RAS may be designed to switch or otherwise affect operation of any of the identified Elements in P5, e.g. ramp generation. But such RAS operations are not intended to clear Faults, as noted above.
RAS which are designed to meet the PRC-012 – 014-WECC-CRT-2 criteria are always designed with a significant level of, though not always complete redundancy. In fact, they are specifically designed to at least meet the “single RAS component failure” language in PRC-012_R1.3 discussed above. Generally, the fact of redundancy will eliminate a WECC-compliant RAS from applicability under P5, even if the Fault clearing intent in P5 had not already eliminated the RAS from applicability under P5.
The delayed Fault clearing in P5 must also be the result of failure of specific relay functions or types. The list in Note 13 is very specific. There is no “expansion” language such as “included but not limited to” for these functions or types. While a RAS may include these functions and/or types, the Note 13 list does not include the function number for a circuit breaker (#52). Since the Note 13 does not specifically include the circuit breaker, P5 does not apply to a circuit breaker associated with a RAS.
In addition, since Table 1, including P4 and P5, only addresses fault clearing plus one other “open” operation (still a breaker trip operation), any RAS which requires a circuit breaker to close, e.g. shunt capacitor insertion, is not anticipated to be addressed by Table 1.
Subsequently, there is no potential for double jeopardy between this WECC variance E1.1.4 and TPL-001-4 Table 1, P4 or P5 because the requirements address operations from different causes.
All of these RAS-associated circuit breaker operations are included in the present language of the FAC WECC variance E1.1.4. The equipment and operations are not covered by either PRC-012_R1.3 or TPL-001-4 Table 1, P4 or P5, so do not raise a double jeopardy hazard for NERC standards compliance. However, the absence of this requirement E.1.1.4, if the proposed retirement is accepted, can and likely will “lower the bar” for reliability of RAS within WECC.
For example, many load shedding RAS are designed to over trip load at multiple sites and/or trip both high and low side breakers on a transformer to be assured that adequate load will be shed even for the failure of a breaker to operate. This approach would no longer be required following retirement of E1.1.4 for either RAS design or SOL determination. In the absence of this level of redundant design or SOL limitations, failure of a single breaker to operate could easily result in the RAS failing to meet the performance requirements referenced in PRC-012 and specified in TPL-001-4. A similar failure to meet the intended System performance could result if the RAS was intended to include switching of shunt capacitors or reactors for voltage control.
So what are the options regarding the proposed retirement of WECC variance E1.1.4 in FAC-010 and FAC-011? These seem to be the possibilities:
• Accept the present proposal to retire E1.1.4.
As discussed above, this may leave a significant hole in RAS reliability within WECC.
• Oppose retirement of variance E1.1.4 with NERC.
It is likely to be difficult to justify keeping either FAC-010 or FAC-011 around just to include this variance.
• Write a similar WECC variance to be included in another appropriate standard. Such a requirement probably fits better as a planning or other design standard than as an operating (SOL) standard.
o TPL-001 could potentially accommodate such a variance. It already applies to an appropriate entity, the TP and the analysis that is required to comply with the present E1.1.4 would also be done by the TP.
o PRC-012 is presently being extensively re-written. As discussed above, the SDT has not included RAS-associated circuit breaker operation in the present draft.
Regional Variance Requirement R1.1.4 addresses failure of a Remedial Action Scheme (RAS)-associated circuit breaker when RAS calls for it to operate. As correctly pointed out by the commenter, the existing Variance is misplaced in FAC-010 and should be relocated.The DT believes that the Regional Variance was not meant to address the failure of the circuit breaker itself; rather, it was intended to address the single point of failure such as trip coils and protection system failure. WECC did not intend the failure of the interrupt mechanism to be part of the RAS. The white paper will be revised to indicate this.
After consideration of the comment received, the drafting team made the following change regarding E.Regional Differences, section 1.1.4, in both white papers:
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.It is recognized that there are minor differences in the language of the two requirements (PRC-012-0 and the Regional Differences section 1.1.4).The PRC Requirement R1.3 does not cover Remedial Action Scheme (RAS)-associated breaker failure other than the trip coil of the breaker.The reliability concern of breaker failure associated with clearing faults is addressed by TPL-001-4, Table 1, P4 and P5.However, the language does not address the failure of a RAS-associated breaker.
Recommendation
Section E. Regional Differences, subsection 1.1.4 of the existing Regional Difference should be reviewed for migration to a different standard as a Regional Variance.[1]

Western Electricity Coordinating Council