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2019-04 Modifications to PRC-005-6 | Standard Authorization Request

Description:

Start Date: 07/30/2019
End Date: 08/28/2019

Associated Ballots:

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Hot Answers

Since the digital AVR has capabilities electromechanical based AVRs do not have, the SAR needs to specify which functions employed by the digital AVR it seeks to address. The Project Scope should state the functions of the digital AVR applicable to the PRC-005 standard. The underlined text should be added:

“Only applicable to a Generator Owner that owns a synchronous generating unit with an installed digital AVR, which is used to disconnect the generator during certain voltage excursions.”

SRC PRC005, Segment(s) 2, 1, 8/28/2019

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In our opinion NERC should add additional comments in the FAQ about applicability.  We believe that the goal is to include functions of the AVR which provide protection for the generator field (i.e. field overcurrent, over-excitation, or V/HZ.  We also believe that the field shunt qualifies as a current input to the protective device.  Ideally NERC will clarify this in the FAQ. We also concluded the part of the DC circuit which goes to the generator lockout falls under the DC circuitry covered by PRC-005-6.  We believe that it is correct to follows the same rules for classifying microprocessor vs non-microprocessor relays when considering AVR's.

David Jendras, On Behalf of: Ameren - Ameren Services, , Segments 1, 3, 6

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Other Answers

Kjersti Drott, On Behalf of: Kjersti Drott, , Segments 1, 3, 5

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Thomas Foltz, On Behalf of: AEP, , Segments 3, 5

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BC Hydro, Segment(s) 3, 5, 1, 12/18/2018

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Dennis Sismaet, On Behalf of: Northern California Power Agency, , Segments 5, 6

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Hydro-Québec TransÉnergie (HQT - RC function) would suggest the following to the SDT:

1.      clarify which protective functions in AVR are relevant protective functions that open a breaker directly or via lockout or tripping auxiliary relays, e.g. should diode failure, field over temperature or field overvoltage protections  be included versus loss of field or generator overvoltage protection;

2.      confirm that external devices e.g. field ground relay, electromechanical field overvoltage are excluded from the scope;

3.      evaluate the possibility of modifying the Protection System definition (NERC Board of Trustees Approved Definition) by including relevant AVR protection functions in the definition, thus table 1-1 will be applicable to AVR with relevant protection functions.

In addition to the proposed project scope, even if no aforementioned (step 1) AVR protective functions are used, the SDT should consider if there will be a benefit to the reliable operation of the BES to verify that settings are as specified (no relevant protection functions are enables) and that measurement of power system input and output values are acceptable. Acceptable AC/DC voltage and current measurements are essential to proper AVR control and verification is not specifically covered in MOD-026-1. The settings changes are covered by R4 of MOD-026-1, as it is in R3 of PRC-001-1.1(ii) for protection relays. MOD-026-1 verification is performed every 10 years whereas PRC-005-6 tables 1-1 is 12 years, SDT should consider coordinating time interval with MOD-026-1 period if a new table is added specifically for the AVR.

Michael Godbout, On Behalf of: Hydro-Qu?bec TransEnergie, NPCC, Segments 1

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Industry understands that protective relaying elements within the excitation control systems are included in the original scope of PRC-005 and no modifications are needed to PRC-005.  NERC should pursue an interpretation of the scope versus modifying a NERC standard.

If a PRC-005 standard revision cannot avoided at this stage, the extent of the revision does not need to expand beyond either footnoting that "Protection Systems" includes protective relaying functions contained within the program logic of the excitation control system or by adding Facilities section 4.2.5.4 to indicate the same. 

The appropriate maintenance activities should match those for microprocessor relays found in the existing Table 1-1 of PRC-005-6.   No revision to the Supplementary Reference and FAQ document is needed because the existing sections addressing microprocessor-based protective relaying already covers that functionality which may exist within excitation control systems rather than within free-standing, discrete, multi-function, microprocessor-based protective relaying solutions

MRO NSRF, Segment(s) 3, 4, 5, 6, 1, 2, 8/19/2019

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Bruce Reimer, On Behalf of: Manitoba Hydro , , Segments 1, 3, 5, 6

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Consider adding Phased Implementation Period for AVRs that provide protection functions to account for outages needed to perform testing.

FE VOTER, Segment(s) 6, 5, 3, 1, 4, 8/22/2019

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Seattle City Light believes that the project scope of this SAR is unclear and likely unnecessary.  The generator AVR’s are already hedged by excitation limiters to prevent under excitation from occurring.  The following points are in response to the SAR:

  1. The occasion in which an AVR trips a generator offline is not likely  to have a significant impact on the BES.  Even the biggest generator going offline will not greatly impact the BES in a meaningful way.  Since each unit has its own AVR the likelihood of major generator tripping is very small.
  2. Other standards already account for this by setting generator limitations for excitation – Excitation system limiters are set in PRC-025-2 to prevent the under excitation of the generator field.  In essence there is already a line of defense in place to prevent such occurrences of the AVR tripping the generator offline.
  3. The implementation of testing AVR tripping is not likely to be cost effective to implement.  As mentioned before there are already methods in place to prevent tripping of the generator via the AVR.  The cost to test these would likely be diminished by the rarity of such a trip occurring and the minor impact it will have on the BES.
  4. Seattle City Light was unclear on which protective functions are being considered in this SAR.  Due to lack of specificity we believe that a change to PRC-005-6 is unnecessary.  If industry is confused on the matter it would be best to revise the FAQ documents, provide industry training at regional/national events or develop an additional white paper on the topic to explore it in greater detail.

Matthew Nutsch, On Behalf of: Seattle City Light, WECC, Segments 1, 3, 4, 5, 6

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Duke Energy, Segment(s) 1, 5, 6, 4/11/2019

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We agree with the scope of the SAR. We do encourage some discussion and consideration of the challenges in “calibrating” the AVR trip settings and forcing the output contacts.  This is the only difference between the AVR and a SEL relay and the industry might end up with very restrictive and possibly hard to implement clarifications on the testing requirements.

DTE Energy - DTE Electric, Segment(s) 5, 4, 3, 2/27/2017

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Exelon supports the NAGF decision to revise PRC-005-6 to specifically address applicability to, and maintenance of, AVR protective functions. 

Daniel Gacek, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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Exelon supports the NAGF decision to revise PRC-005-6 to specifically address applicability to, and maintenance of, AVR protective functions. 

Kinte Whitehead, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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Exelon supports the NAGF decision to revise PRC-005-6 to specifically address applicability to, and maintenance of, AVR protective functions. 

Cynthia Lee, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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Exelon supports the NAGF decision to revise PRC-005-6 to specifically address applicability to, and maintenance of, AVR protective functions. 

Becky Webb, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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Jeanne Kurzynowski, On Behalf of: CMS Energy - Consumers Energy Company - RF - Segments 1, 3, 4, 5

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Under Detailed Description section of the SAR:

Other sections of the standard also need to be revised accordingly. In PRC-005-6 section 6 the definition for AVR and AVR protective function need to be added as AVR does not appear anywhere in the NERC glossary.

The PRC-005-6 table section needs to be revised and a table added to clearly identify AVR protective functions and their testing requirements.

 

Thomas Breene, On Behalf of: WEC Energy Group, Inc., , Segments 3, 4, 5, 6

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Xcel Energy agrees this is a necessary addition to PRC-005-6 to clarify the applicability and limit the scope.  We believe the standard should be neutral to type of generating resource and question why PRC-005-6 should not also apply to electrical protective functions implemented on control systems of inverter-based resources that can cause tripping of BES generating resources.

Further, we note the scope of 2017-07 - Standards Alignment with Registration also includes modifications to the applicablity section of PRC-005 related to UFLS Only Distribution Providers.  We encourage the teams to work together to most efficiently make the necessary modifications.

Amy Casuscelli, On Behalf of: Xcel Energy, Inc. - MRO, WECC - Segments 1, 3, 5, 6

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Submitted on behalf of CHPD:

The scope appears to presume that PRC-005 is applicable to the AVR.  We do not agree.   WECC has provided guidance that voltage regulators are not within scope of PRC-005.  Voltage Regulators are not Protective Relays which is the applicability of PRC-005. 

While we disagree, if it is determined an AVR falls within the scope of PRC-005, the specific AVR protective functions that are included in the scope should be limited to those functions that are similar to electrical protective relay functions, not internal AVR or exciter functions not detected by conventional protective relays, regardless if these functions cause shutdown of excitation and the opening of a breaker.

Ginette Lacasse, On Behalf of: Public Utility District No. 1 of Chelan County, WECC, Segments 1, 3, 5, 6

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LG&E/KU believes that the standard is already explicit on Point 1, and that only elements that open a breaker directly or via a lockout or tripping relay are applicable. Guidance should be requested that specifically excludes control devices which perform protective tripping as an accessory (digital excitation controllers, programmable logic controllers, distributed controllers, etc.) from the requirements of Table 1-1. If these devices are in scope, a test methodology and criteria should be provided. Guidance and/or a methodology should also be provided regarding the applicability of Table 1-3 to field sensing via DC shunt circuits

Louisville Gas and Electric Company and Kentucky Utilities Company, Segment(s) 3, 5, 6, 9/6/2018

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The primary function of AVRs is to control/regulate unit voltage. Although some AVRs can be set to trip generators, they are not primary protective relays. AVR protective functions do not affect the reliability of the Bulk Electric System with respect to faults or system disturbances, as the items currently listed in PRC-005-6 do. The inclusion of AVR protective functions goes beyond the scope of the NERC definition for Protection Systems and would establish a worrying precedent for including numerous other equipment for which the primary function is not protective; for this reason, PRC-005 should have a scope limit. Maintenance of AVR functions would be better suited to the VAR Standard family, which addresses AVR performance.

Glenn Barry, On Behalf of: Los Angeles Department of Water and Power, , Segments 1, 3, 5, 6

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 In so much as the protective relaying elements are standard or optional sections of a generator's excitation control system and since the functionality and purpose of such protection elements within excitation control systems are equivalent to standalone, traditional, multi-function microprocessor-based protective relays, it is clear to protection relay engineers that those protection elements within the excitation control systems are included in the original scope of PRC-005, whether or not they currently are explicitly delineated or identified.  Furthermore, the execution of any programmed unit tripping logic sourced from protection elements which may be used with excitation control systems very often use the same dc control circuitry for tripping of the generating unit as do the external microprocessor-based and electromechanical protective relays.  It is our belief that no modifications are needed to PRC-005, and that the scope of applicability already includes these elements.  An interpretation of the scope, in our opinion, would provide clear, unambiguous, an adequate indication of the inclusion of these protective elements of excitation control equipment, and no modification to PRC-005-6 is needed.     

If a PRC-005 standard revision cannot be restrained and avoided at this stage, the extent of the revision does not need to expand beyond either footnoting that "Protection Systems" to indicate that this includes any used protective relaying functions contained within the program logic of the excitation control system or by adding Facilities section 4.2.5.4 to indicate the same.   The following action is recommended to address the maintenance activity request in the SAR:   Since the programming, testing, and functionality of generator protective relaying elements in use within excitation control systems is essentially identical to that provided by multi-function microprocessor-based discrete protective relaying, the appropriate maintenance activities match those for microprocessor relays found in the existing Table 1-1 of PRC-005-6.   These 6 calendar year activities are:   1)  verify that the settings in the device, 2)  verity the digital inputs & outputs are functional,  3)  verify that the analog inputs are transduced properly (analog/digital conversion).  We believe that no additional discussion or specification of the myriad of possible protective relaying functionality and testing methods is necessary or needed.   The test methods are similar to those used for microprocessor-based protective relays.  As with other discrete multi-function microprocessor-based protective relaying, only those elements that are chosen to be used in the protective device should be in the scope of maintenance activities required by PRC-005.  No revision to the Supplementary Reference and FAQ document is needed because the existing sections addressing microprocessor-based protective relaying already covers that functionality which may exist within excitation control systems rather than within free-standing, discrete, multi-function, microprocessor-based protective relaying solutions.     

Southern Company, Segment(s) 1, 6, 3, 5, 9/1/2016

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Sandra Shaffer, On Behalf of: Sandra Shaffer, , Segments 6

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Reclamation supports the existing content of the SAR. In addition, Reclamation recommends expanding the scope of the SAR. The SAR should address a course of action for PRC-005 to specify a process for carrying out maintenance that is missed during equipment overhauls or other unavailability during the required maintenance interval. The revised standard should address the allowable timelines to perform the required maintenance. The timelines should permit the missed maintenance to be performed either prior to returning the equipment to Commercial Operation or prior to closing in the breaker. The measure for Requirement R3 should be updated to include documentation that allows for the extension of the interval while the equipment is not connected to the BES.

Reclamation also recommends adjusting the scope of the SAR to include clarification of the language used in R5 for corrective maintenance activities. Specifically, Reclamation recommends clarifying the information required to be documented for each Unresolved Maintenance Issue. Examples of documentation may include, but are not limited to: work orders, invoices, project schedules with completed milestones, purchase orders, procedure and/or test results.

Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5

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We would suggest the following to SDT:

1.      Clarify which protective functions in AVR are relevant protective functions that open a breaker directly or via lockout or tripping auxiliary relays, e.g. should diode failure, field over temperature or field overvoltage protections be included versus loss of field or generator overvoltage protection;

2.      Confirm that external devices e.g. field ground relay, electromechanical field overvoltage are excluded from the scope;

3.      Evaluate the possibility of modifying the Protection System definition (NERC Board of Trustees Approved Definition) by including relevant AVR protection functions in the definition, thus table 1-1 will be applicable to AVR with relevant protection functions.

In addition to the proposed project scope, even if no aforementioned (step 1) AVR protective functions are used, the SDT should consider if there will be a benefit to the reliable operation of the BES to verify that settings are as specified (no relevant protection functions are enables) and that measurement of power system input and output values are acceptable. Acceptable AC/DC voltage and current measurements are essential to proper AVR control and verification is not specifically covered in MOD-026-1. The settings changes are covered by R4 of MOD-026-1, as it is in R3 of PRC-001-1.1(ii) for protection relays. MOD-026-1 verification is performed every 10 years whereas PRC-005-6 tables 1-1 is 12 years, SDT should consider coordinating time interval with MOD-026-1 period if a new table is added specifically for the AVR.

RSC, Segment(s) 10, 2, 4, 5, 7, 3, 1, 0, 6, 8/1/2019

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Black Hills is comfortable with the current language of the standard in terms of how to treat protection function testing/maintenance relating to PRC-005-6 and AVR systems.

Maryanne Darling-Reich, On Behalf of: Black Hills Corporation - MRO, WECC - Segments 1, 3, 5, 6

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Rachel Coyne, On Behalf of: Texas Reliability Entity, Inc., , Segments 10

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We agree with CHPD's comments.

Ted Hobson, On Behalf of: Ted Hobson, , Segments 1, 3, 5

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NYPA supports this SAR. However, the project scope may need to consider AVR applicability under other NERC PRC standards applicable to Protection Systems (e.g., PRC-004-5 Protection System Misoperation Identification and Correction).

Thomas Savin, On Behalf of: Thomas Savin, , Segments 1, 3, 5, 6

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In the Detailed Description Section, the first point specifies “Revise PRC-005-6 to add a new section under Facilities to clearly delineate the applicability of Protection Systems associated with AVR protective functions.” It is unclear if the intent is to revise the definition of Protection System, or to add a section to the “Facilities” section of the Standard for AVR protective functions (similar to Sudden Pressure Relaying). The SAR should be revised to clarify. Suggested revision: “Revise PRC-005-6 to add a new section under Facilities to clearly delineate the applicability of Automatic Voltage Regulators and their associated protective functions. This new section needs to clearly limit the scope of the AVR protective functions to those elements that open a breaker directly or via lockout or tripping auxiliary relays.”

PRC-024 SDT is already modifying language to address this for inverter-based resources and the “momentary cessation” issue, so this may be in conflict what with the PRC-005 SAR team does: “Frequency, voltage, and volts per hertz protections (whether provided by protective relaying or protective functions imbedded within associated control systems) that respond to electrical signals and: (i) directly trip the generating resource(s); or (ii) provide signals to the generating resource(s) to either trip or cease injecting current; and are applied on any of the following…..”

brian robinson, On Behalf of: Utility Services, Inc. - NPCC - Segments 5

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Comments: EEI member companies support the SAR but offer clarifying language for NERC consideration.  Using the term “synchronous” as contained within the SAR scope section (i.e., Detailed Description/Unique Characteristics part of the SAR) by itself may unintentionally add ambiguity for some entities and BES resource owners.  This term, as used within the SAR, is unbounded and may incorrectly cause some entities or auditors to include some aggregate variable resources and diesel resources that are connected to the BES and have digital AVRs that directly trip individual units. 

Suggested Modifications:

EEI asks that additional language be added to the SAR to more clearly define which resources are to be included within the applicability section of PRC-005-6.  One possible solution would be to simply state within the Scope that changes intended to address digital AVR systems are to be limited to “Large” synchronous generating units with installed digital AVR.  (EEI notes that the SDT should define what constitutes “Large” within the applicability section of the revised standard.)   Alternatively, the scope could be modified to add language that limits AVR applicability to units that have a single shaft rating of 20 MVA, and greater, and if the units are smaller than 20 MVA, they should be excluded altogether.  We also suggest adding language that limits the applicability of aggregated plant level AVRs, or equivalent controllers, to those that trip the entire aggregate plant of 75 MVA, not individual units AVR.

Mark Gray, On Behalf of: Edison Electric Institute, NA - Not Applicable, Segments NA - Not Applicable

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The AVR protective settings should be coordinated with Protection System settings and configuration.  The BES Protection System devices should be separate from the AVR.  The AVR should not be used as a substitute to BES Protection System devices.  While the AVR may trip the unit from the BES it may not be used to protect the BES in the event of an AVR failure.

LCRA Compliance, Segment(s) 6, 5, 1, 5/11/2015

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In addition to the project scope outlined in the SAR, it is recommended that a revision to PRC-005-6 be added to the scope to clearly define the applicability found in Section 4.2.1 to state BES Lines, transformers, and buses including breakers associated with each of those elements.  This language would clarify the exact items Regional Entities are requesting during requests for information. The inclusion of “etc.” in the standard does not provide the desired clarity.

ACES Standard Collaborations, Segment(s) 1, 3, 4, 5, 8/28/2019

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Hot Answers

Southwest Power Pool understands that newer technology may raise questions on how existing NERC standards apply to it. We see a trend with this SAR and recent projects to address performance of digital based equipment.  In moving forward, the drafting team should be aware that technology will change and standards should be as technology neutral as possible.  If the requirements focus on the reliability intent or “what”, we believe that would accommodate as many different technologies as possible and avoid frequent updates to address how new technologies apply.

SRC PRC005, Segment(s) 2, 1, 8/28/2019

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In our opinion it would helpful for NERC to provide guidance on approaches and methods to meet compliance with the AVR portion of requirements of PRC-005.  In our opinion the drafting team needs to make it clear that the owner does not have to test the control functions of the AVR to meet these requirements.  NERC has already stated that the field breaker is not covered under the standard.  It would also be beneficial to give some examples for various types of excitation and AVR's.

David Jendras, On Behalf of: Ameren - Ameren Services, , Segments 1, 3, 6

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Other Answers

Kjersti Drott, On Behalf of: Kjersti Drott, , Segments 1, 3, 5

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Thomas Foltz, On Behalf of: AEP, , Segments 3, 5

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BC Hydro, Segment(s) 3, 5, 1, 12/18/2018

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Dennis Sismaet, On Behalf of: Northern California Power Agency, , Segments 5, 6

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Hydro-Québec TransÉnergie (RC function) is about to file a SAR on PRC-005 as well. It would be opportune to consider integrate this second SAR into the current proposed SAR. This second SAR proposes to make the Standard technology neutral and allow performance-based maintenance practices for batteries.

Current standard PRC-005-6 requires time-based maintenance program for technology-specific batteries in tables 1-4. Certain entities have identified that current prescribed time-based maintenance programs in tables 1-4 for the batteries did not achieve the desirable outcome. That is, the batteries would not perform as designed when called upon by the protection systems.

A comparison of maintenance intervals and activities prescribed by the Standard with recommended practices in standards IEEE 450-2010, 1188-2005 and 1106-2015 (maintenance and test sections) confirm that the prescribed maintenance intervals and activities are less stringent. These IEEE references also recommend the adjustment of maintenance intervals so that batteries perform as expected when needed. This finding is further supported by the EPRI technical report “Stationary Battery Guide: Design, Application, and Maintenance”.  Therefore, extending the performance-based approach allowed for all the non-battery components to include the batteries would ensure adequate maintenance frequencies for their components and conform with section 2.4 of the NERC Standards Processes Manual. This is important for all technologies, including new technologies for which operating experience is insufficient to establish a time-based maintenance.

Currently, Hydro-Quebec and other entities are considering the replacement of existing batteries with batteries using a new battery technology based on Lithium that is cost-effective and more reliable. These new batteries are not identified in PRC-005-6 and compliance concerns due to technology-specific tables are causing undue restrictions and adverse impact on the competitiveness as defined in section 2.3 of the NERC Standards Processes Manual.

While adding a performance-based approach for the batteries, the PRC-005-6 Reliability Standard can also benefit by revising its performance-based approach in line with the performance-based approaches documented in EPRI technical report “Reliability and Preventive Maintenance: Balancing Risk and Reliability”. The maintenance intervals in the tables could be moved to a guideline for compliance with the standard and appendix A could be revised to better reflect the EPRI report.

See attached the proposed second SAR.

Michael Godbout, On Behalf of: Hydro-Qu?bec TransEnergie, NPCC, Segments 1

PRC-005-6 - SAR.secure-updated 2019-08-21.docx

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Key Issue:

Using synchronous in the SAR scope by itself leaves a gap and ambiguity for some units.  Synchronous isn’t sufficient as some small aggregate variable or diesel plants can have synchronous connected units with digital AVRs that directly trip the individual units.  Type 1 wind generators or squirrel cage induction generators can still be considered synchronous.  Type 3 Doubly Fed Induction Units can be considered synchronous.

Suggested SAR Scope Change:

Further define what is in and out-of-scope in the applicability section of PRC-005-6.  Limit scope to units with a single shaft of 20 MVA and greater consistent with PRC-002-2 R5 and the NERC registration criteria.  If the units are smaller than 20 MVA, they are excluded.  Include aggregate plant level AVRs or equivalent controllers that trip the entire aggregate plant of 75 MVA or more

Suggested PRC-005 Applicability Revision or Addition:

Synchronous Generating resource(s) with digital AVR protective functions that trip the plant directly or via lockout or tripping auxiliary relays where:

  • Gross individual single-shaft nameplate rating greater than or equal to 20 MVA.
  • Gross individual nameplate rating greater than or equal to 20  MVA where the gross plant/facility aggregate nameplate rating is greater than or equal to 75 MVA or greater.

Supporting Material:

See the NREL descriptions of both Type 1 and Type 3 wind turbines:

https://www.nrel.gov/docs/fy12osti/52780.pdf

Key Issue:

Using synchronous in the SAR scope by itself leaves a gap and ambiguity for some units.  Synchronous isn’t sufficient as some small aggregate variable or diesel plants can have synchronous connected units with digital AVRs that directly trip the individual units.  Type 1 wind generators or squirrel cage induction generators can still be considered synchronous.  Type 3 Doubly Fed Induction Units can be considered synchronous.

 

Suggested SAR Scope Change:

Further define what is in and out-of-scope in the applicability section of PRC-005-6.  Limit scope to units with a single shaft of 20 MVA and greater consistent with PRC-002-2 R5 and the NERC registration criteria.  If the units are smaller than 20 MVA, they are excluded.  Include aggregate plant level AVRs or equivalent controllers that trip the entire aggregate plant of 75 MVA or more

 

                        Suggested PRC-005 Applicability Revision or Addition:

Synchronous Generating resource(s) with digital AVR protective functions that trip the plant directly or via lockout or tripping auxiliary relays where:

        • Gross individual single-shaft nameplate rating greater than or equal to 20 MVA.
        • Gross individual nameplate rating greater than or equal to 20  MVA where the gross plant/facility aggregate nameplate rating is greater than or equal to 75 MVA or greater.

 

Supporting Material:

See the NREL descriptions of both Type 1 and Type 3 wind turbines:

https://www.nrel.gov/docs/fy12osti/52780.pdf

 

Type 1 induction generators are synchronously connected and generate power when spun faster than 60 Hz.  Type 3 doubly fed induction generators have two power paths, a real power path that goes through an inverter / converter which is asynchronous and a reactive power path that is synchronously connected to the grid, hence DFIG (Doubly Fed Induction Generator)

Type 1 – Induction Units:

This chapter describes the development of a generic dynamic model for a fixed-speed wind turbine, the most basic type of utility-scale wind turbine in operation today. Fixed-speed wind turbines are called so because they operate with less than 1% variation in rotor speed. They employ squirrel-cage induction machines directly connected to the power grid.  A large number of fixed-speed wind turbines have been installed over the past decade and a half, and more continue to be installed.

Type 3 – DFIG Induction Units:

The model for the Type-3 wind turbine generator is built using PSCAD/EMTDC software. It is based on the WECC general model, developed by the Wind Generator Modeling Group of the WECC [24].

4.3.1 Doubly-Fed Induction Generators: Basic Concepts

A rotating machine is said to be a generator when it is converting mechanical input power to electrical output power. When induction machines are operated at speeds greater than their synchronous speeds, they act as generators. DFIGs operate on the same principles as conventional wound-rotor induction generators with additional external power electronic circuits on the rotor and stator windings to optimize the wind turbine operation. These circuits help extract and regulate mechanical power from the available wind resource better than would be possible with simpler squirrel-cage induction generators. A schematic representation of a DFIG wind turbine system is shown in Figure 4.1.

 

MRO NSRF, Segment(s) 3, 4, 5, 6, 1, 2, 8/19/2019

Project 2019-04_SAR_PRC-005-6 Final.docx

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Bruce Reimer, On Behalf of: Manitoba Hydro , , Segments 1, 3, 5, 6

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FE VOTER, Segment(s) 6, 5, 3, 1, 4, 8/22/2019

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None

Matthew Nutsch, On Behalf of: Seattle City Light, WECC, Segments 1, 3, 4, 5, 6

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Duke Energy agrees with scope of proposed SAR.  Duke Energy requests confirmation that protective functions from other control systems are not included in Standard scope (e.g., turbine frequency and overspeed trips).  Additionally, request confirmation that SAR is only applicable to digital AVR’s and control systems.

Duke Energy notes that the term protective function is referenced in several NERC Standards and other Region documentation but is not defined in the NERC Glossary – suggest adding Protective Function definition to NERC Glossary.  Some regions (e.g., SERC and RF) have provided AVR protective function guidance.  Duke Energy requests that the ERO develop consistent documentation.

Duke Energy, Segment(s) 1, 5, 6, 4/11/2019

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Guidance is needed in order to insure that AVR protective functions comply with PRC-005-6.

DTE Energy - DTE Electric, Segment(s) 5, 4, 3, 2/27/2017

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No additional comments.

Daniel Gacek, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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No additional comments.

Kinte Whitehead, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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No additional comments.

Cynthia Lee, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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No additional comments.

Becky Webb, On Behalf of: Exelon, , Segments 1, 3, 5, 6

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Jeanne Kurzynowski, On Behalf of: CMS Energy - Consumers Energy Company - RF - Segments 1, 3, 4, 5

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WEC Energy Group suggests that the SAR authors consider reviewing NERC definition of Protection System and identify if the AVR is part of Protection Systems.

WEC Energy Group further suggests that the AVR is not a protective relay but a controls system. The AVR controls will trip the unit off if it detects malfunctions in the AVR which would cause it to cease operating.

Therefore, the project scope should be: Revise PRC-005-6 to clearly state that PRC-005-6 does not apply to AVRs.

Thomas Breene, On Behalf of: WEC Energy Group, Inc., , Segments 3, 4, 5, 6

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We also suggest including shunts to the Voltage & Current Sensing Devices section of the PRC-005-6 Supplementary Reference and FAQ documents.

Amy Casuscelli, On Behalf of: Xcel Energy, Inc. - MRO, WECC - Segments 1, 3, 5, 6

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Ginette Lacasse, On Behalf of: Public Utility District No. 1 of Chelan County, WECC, Segments 1, 3, 5, 6

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Louisville Gas and Electric Company and Kentucky Utilities Company, Segment(s) 3, 5, 6, 9/6/2018

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Glenn Barry, On Behalf of: Los Angeles Department of Water and Power, , Segments 1, 3, 5, 6

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Southern Company, Segment(s) 1, 6, 3, 5, 9/1/2016

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No comments at this time.

Sandra Shaffer, On Behalf of: Sandra Shaffer, , Segments 6

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Reclamation recommends the SDT also evaluate the validity of the 12-year interval for PT and CT tests, with specific consideration to shortening the interval. The long interval has the result of only identifying failure of this equipment when it happens, rather than offering a preventive window to implement corrections before failure. The effect of such a lengthy interval is more of an administrative exercise, rather than improving BES reliability.

Richard Jackson, On Behalf of: U.S. Bureau of Reclamation, , Segments 1, 5

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RSC, Segment(s) 10, 2, 4, 5, 7, 3, 1, 0, 6, 8/1/2019

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Maryanne Darling-Reich, On Behalf of: Black Hills Corporation - MRO, WECC - Segments 1, 3, 5, 6

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Texas RE recommends the drafting team clarify the description of AVR.  This could be done in a Technical Rationale document or the rationale boxes with the standard drafts.   The drafting team may wish to consider the information provided in the WECC Regional Variance regarding control loops working in conjunction with AVR.  Also, consider wind generators have varying descriptions of their AVR systems.  Additional clarity will help industry implement PRC-005-6.

Rachel Coyne, On Behalf of: Texas Reliability Entity, Inc., , Segments 10

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Ted Hobson, On Behalf of: Ted Hobson, , Segments 1, 3, 5

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Thomas Savin, On Behalf of: Thomas Savin, , Segments 1, 3, 5, 6

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brian robinson, On Behalf of: Utility Services, Inc. - NPCC - Segments 5

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Comments: EEI understands that North American Generator Forum was instrumental in studying this issue and developing this SAR.  As a result, if there are any whitepapers that have been written in support of this effort, we ask that they be added and references within SAR.

Mark Gray, On Behalf of: Edison Electric Institute, NA - Not Applicable, Segments NA - Not Applicable

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BES Protection System devices should be utility grade protective devices with the ability to withstand voltage transients according to (but not limited to) ANSI/IEEE C37.90.x and include surge protection according to ANSI/IEEE C62.41.x.

LCRA Compliance, Segment(s) 6, 5, 1, 5/11/2015

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Thank you for the opportunity to comment.

ACES Standard Collaborations, Segment(s) 1, 3, 4, 5, 8/28/2019

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