Comment Report Form for WECC-01011
Posting 5
The WECC-0101 Variance Drafting Team (DT) thanks everyone who submitted comments on the proposed documents.
Posting
This document was last posted for a 30-day public comment period from July 7 through August 6, 2015.
WECC distributed the notice for the posting onJuly 2, 2015. The DT asked stakeholders to provide feedback on the proposed document through a standardized electronic template. WECC received comments fromfive companies representing five of the eight Industry Segments, as shown in theWECC Standards Voting Sector Table that follows. Comments were also received from the Public Utility District No. 1 of Snohomish County that is not currently registered in the WECC Ballot Body.
Location of Comments
All comments received on the document can be viewed in their original format on the project page under the “Submit and Review Comments” accordion.
Changes in Response to Comment
In response to Public Service Company of New Mexico, the following non-substantive change was made to MOD-026, E.B.2.1.1 to clarify when the staged test was conducted. The drafting team’s response also indicates that there is no time limit as to when the staged test was conducted; therefore, the referenced test could be either quite recent or it could be quite old.
E.B.2.1.1.1The recorded response used for Requirement R2.1.1 shall be from either of the following:
- A staged test of the unit; (or)
- A measured system disturbance supported by previously conductedstaged test. (Emphasis added)
After reviewing the comments submitted in response to Posting 5, the DT made no further substantive changes to the project.
Implementation Plan
The Implementation Plan was presented in detailed form in Posting 5 and has been retained there during the development phase of this project.
Action Items
There are no previous action items pending.
Action Plan
On August 11, 2015, the DT met to consider and address comments received during Posting 5 of this project. Having made no further substantive changes to the project the DT agreed by majority vote to forward the project to the WECC Standards Committee (WSC) with a request for ballot. The WSC will meet on August 12, 2015.
The project will also be forwarded to the North American Electricity Reliability Corporation (NERC) with a request for 45-day posting under the NERC Rules of Procedure.
Contacts and Appeals
If you feel your comment has been omitted or overlooked, please contact W. Shannon Black, Consultant, WECC Standards Processes, at . In addition, there is a WECC Reliability Standards Appeals Process.
WECC Standards Voting Sector Table
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 Sectors1 / 2 / 3 / 4 / 5 / 6 / 7 / 8
1 / Laurie Williams / Public Service Company of New Mexico / X / X / X
2 / Kaleb Brimhall / Colorado Springs Utilities / X / X
3 / Chad Edinger / City of Tacoma Power / X / X
4 / Michelle Amarantos / Arizona Public Service Company / X / X / X / X / X
5 / Kenn Backholm
(Note: Snohomish is not registered in the WECC Ballot Body as of August 10, 2015.) / Public Utility District No. 1 of Snohomish County / -
6 / Sergio Banuelos / Tri-State Generation and Transmission / X / X / X / X / X
Index to Questions, Comments, and Responses
Question
- The Drafting Team welcomes comments on all aspects of the document.
- The Drafting Team welcomes comments on all aspects of the document.
Summary Consideration: / See summary in the preamble of this document.
Commenter / Yes / No / Comment
Public Service Company of New Mexico / PNM appreciates the work of the drafting team and provides the following comments/questions, which may improve clarity of variance and provide insight into variance's intent, for the team's consideration:
MOD-026-1
R2.1.1 Documentation demonstrating the applicable unit's model response matches the recorded response for a voltage excursion for either a staged test or a measured system disturbance.
E.B.2.1.1.1 The recorded response used for Requirement R2.1.1 shall be from either of the following;
- A staged test of the unit; (or)
- A measured system disturbance supported by a stage test.
R4 Each GO shall provide revised model data or plans to perform model verification (in accordance with Requirement R2) for an applicable unit to its TP within 180 calendar day of making changes to the excitation control system or plant volt/var control function that alter the equipment response characteristics.
E.B.4 Each GO shall provide to its TP, revised model data or its plans to perform model verification (in accordance with Requirement R2) for an applicable unit, within 180 calendar days of making changes to the excitation control system or plant volt/var control function that alter the equipment response characteristics, except when the change is 180 days or less in duration.
The only difference between the NERC requirement and the Regional Variance appears to be the language "expect when the change is 180 days or less in duration." What is the reason behind including this exception? Shouldn't a TP be notified of a change that will alter the equipment response characteristics even if the changes is for less than 6 months? To avoid WECC receiving models that are valid for 6 months or less WECC should put out a Regional Business Practice stating that changes with an anticipated duration of 180 days or less should not be submitted to WECC.
MOD-027-1
R4. Each GO shall provide revised model data or plans to perform model verification (in accordance with Requirement R2) for an applicable unit to its TP within 180 calendar days of making changes to the turbine/governor and load control or active power/frequency control system that alter the equipment response characteristics.
E.B.4 Each GO shall provide revised model and validation data, or its plans to perform model verification for an applicable unit, (in accordance with Requirement R2) to its TP, to include each of the following numbered items describing modification to its turbine, governors, power and frequency control system, if any, each time such a modification changes the equipment response characteristic, with 180 day of making a change expect when the changes is 480 days of less in duration.
- Response characteristics from DC to 1 Hz that includes effects of load and plant control loops, if any;
- Steady state droop;
- For hydro units report the steady state power vs. gate position (and blade angle if applicable) characteristics
As an overall comment, PNM is not clear on the reliability benefit provided by the variance and would encourage the drafting team to consider that as it works toward the variance. Thank you.
MOD-026-1
R2.1.1/E.B.2.1.1.1: Measured System Disturbance/Staged Test
To clarify the language the following non-substantive change has been made:
E.B.2.1.1.1The recorded response used for Requirement R2.1.1 shall be from either of the following:
- A staged test of the unit; (or)
- A measured system disturbance supported by previously conductedstaged test. (emphasis added)
The support by a staged test means that the model was developed using data from a series of staged tests. An essential feature of the WECC Policy that is neglected in the NERC standards, that baseline testing, i.e., a complete model validation is performed on all units, at least once for the model development. Use of disturbance data should only be used to prove the existing model was developed sufficiently, and is still adequate. It is a weakness in the MOD standards to allow disturbance data without completion of a full “baseline” validation.
R4: Reason for 180 days
A model should be updated anytime the equipment response changes. However, if the modification is temporary, e.g., for a temporary operational constraint, or maintenance/replacement, the model validation process would exceed the time period of the response modification, and a model substitution would not be appropriate.
Internal Practices
The DT encourages Public Service Company of New Mexico to author the suggested Standards Authorization Request and work directly with WECC staff to initiate the suggested project. In the alternative, the proposed practice might be best served as a regional Guideline administered by the associated Standing Committee and created under the rules of that Standing Committee.
MOD-027-1
R4: 180 days
See above response to MOD-26.
Colorado Springs Utility / Thank you drafting team for all of your work. CSU believes that the proposed WECC variances do not improve upon or add important requirements to the already approved NERC standards (MOD-026, MOD-027, MOD-032, and MOD-033). CSU recommends that this project is closed without creating regional variances for MOD-026 and MOD-027. More requirements will not improve reliability. Let's implement the already approved NERC standards effectively.
CSU has not received any evidence justifying the reliability need for the proposed variance. The white papers published striving to demonstrate the need for a 5 year re-validation of models do not contain sufficient evidence to merit the more stringent 5 year requirements, especially since the NERC standards have requirements that require the re-validation of units post modifications that would affect modeling characteristics.
CSU also agrees with the comments submitted by PNM for posting 5. As pointed out by the PNM comments, many of the variance requirements mirror the NERC requirement closely enough as to eliminate the need for the variance requirement altogether.
CSU recommends that this project is closed without creating regional variances for MOD-026 and MOD-027. More requirements will not improve reliability. Let's implement the already approved NERC standards effectively.
Thank You!
Issue 1: Quash/White Paper is Insufficient
The DT appreciates CSU’s position. Procedurally, the DT has been charged by the WECC Standards Committee (WSC) to develop the project in accordance with the Reliability Standards Development Procedures (Procedures); therefore, the DT declines to accept CSU’s invitation to quash the project.
The DT remains convinced that the project will bring a tiered degree of additional reliability to the Interconnection. The DT notes that “how much” additional reliability is an entity-specific value-judgment based on the provided empirical evidence as viewed through the expertise and practices of the reviewing entity. As such, the “value” of the project will vary from one entity to the entity.
Issue 2: Agreement with PNM’s Comment
Please see response to PNM.
City of Tacoma Power / Referencing MOD-026 E.B.2.1.1.1 second bullet: Use of a measured system disturbance as a means of validation seems to be rendered useless if they must be supported by a staged test. Suggest making requirements consistent with how it is laid out for WECC's variance to MOD 27.
Issue 1: MOD-026 E.B.2.1.1.1,Bullet 2 / Recommend consistency with MOD-27
Please see response to PNM addressing E.B.2.1.1.1 wherein the need for the staged test is reiterated.
AZPS / AZPS appreciates the efforts of the drafting team; however, AZPS does not support the WECC regional variance. To accommodate for differences in the Regional variance and MOD-026-1 with regard to the threshold of MVA being tested, AZPS notes MOD-026-1 presently accommodates a Transmission Planner requesting additional testing of a technically justified unit.
Also, the technical paper provided to demonstrate the efficacy of a five-year revalidation policy does not offer persuasive justification. For instance, both damping oscillations depicted (see page 4) would result in equivalent decision making (e.g., the trip point is set to 59.5 Hz). Similar positions may be advanced with regard to the Frequency and Voltage deltas depicted. The deltas are not technically significant to change any operating or planning decisions and do not justify more frequent model validation.
However, the technical paper does help illustrate the progress model validation efforts have made since their 1996 inception. AZPS believes since 1996 the deltas have narrowed significantly. A study covering this wider view may help prove the theory that over time and going forward, less frequent testing may be warranted.
AZPS believes that if the variance is technically justified and warranted then the changes should be implemented continent wide. This can be done by drafting a SAR and submitting it to NERC for continent-wide standard revision.
Issue 1: Accommodate Threshold
The additional testing of a technically justified unit can only be requested if the Transmission Planner has evidence, which will not be the case for the overwhelming majority of plants.
Issue 2: White Paper / Delta’s Technically Insignificant
Please see response to CSU.
The DT would point APZS to the following language excerpted from the Summary, page 17 of the technical paper:
“Since the Double Palo Verde outage and the BC-Alberta separation scenarios are contingencies used for setting operating limits on the California-Oregon Intertie, the model differences could result in different operating limits that effectively alter reliability margins and revenue potential or capital costs.”
Issue 3: Continent Wide
The point of the study was to examine 5-year changes vs. 10-year. The case could be easily modified so that the simulations would result in difference in tripping vs. no tripping. The point of tripping is relative, and could be different between cases.
The DT believes that technical justification exists for the WECC, but does not suggest there is any justification for the other interconnections.
Snohomish / Public Utility District No. 1 of Snohomish County supports the response to Posting 5 that was submitted by Kaleb Brimhall of Colorado Springs Utilities. Thank you.
Please see response to CSU.
Tri-State / After reviewing the 2nd Technical Paper released in June, Tri-State still continues to believe that the proposed WECC variances do not improve the reliability of the BES and rather add undue burden. Tri-State feels that the requirements and associated intervals (R2 & R4) in the NERC standards are adequate for future preservation and maintenance of the system model. In Tri-State's opinion, the 2nd Technical Paper did not contain sufficient evidence to support the stricter 5 year requirements, as the source of the generator model changes between intervals is not known. (i.e. Were the changes related to equipment modifications, drift, previous model errors, or some other cause.) We continue to believe that proposing a regional variance based solely on the continuation of a legacy policy is not a valid reason.
MOD-026-1 and MOD-027-1 will help improve the models and overall reliability of the BES. Tri-State would like to allow for some time following the effective dates to determine if a variance is needed to improve reliability of the BES and System Models.
The 2nd Technical Paper states that not all the Generator Owners followed the WECC policy so many models were not revalidated within that time period. It also states that a quarter of the models in the database weren't recalibrated so that might be the reason WECC's model varies. However, now the industry must comply with the NERC standards so this issue will already be resolved.
Tri-State also agrees with and supports the comments submitted by CSU and PNM.
Issue 1: White Paper
Please see response to CSU.
Issue 2: Legacy
The cause of model differences is not relevant. The point is that models do indeed change for many reasons.
The DT appreciates Tri-States position reiterated from its Posting 4 comments.
The DT also agrees with Tri-Statethat standards should not be based solely on the continuation of a legacy policy. This argument applies equally to the underlying standard as it does to the existing WECC policy. To avoid the quagmire of legacy, this project is being afforded due process afresh. The DT encourages Tri-State and all participating entities to review all of the available information and cast its ballot accordingly.
Issue 3: 2nd Technical paper / Following NERC Standards resolves the Issue
Models that were not recalibrated did not change, and therefore do not contribute to the overall response change between cases. The point in the study was to examine the changes in the database. Had the additional models been modified in the time frame examined, the results would only indicate a greater difference in models and results.
As to the “wait and see” approach, the DT suggests that the industry would be faced with the same subjective question it attributes to the technical support. “How long is long enough” sounds smartly like “how much data is enough”.
Issue 5: Support of CSU and PNM
Please see responses above.
Western Electricity Coordinating Council