Standard MOD-26-1 with WECC Variance – Verification of Models and Data for Generator Excitation Control System or Plant Volt / VAR Control Function

StandardDevelopmentRoadmap

This section is maintained bythedrafting team during the development of thestandard and willbe removedwhen thestandard is approved.

AnticipatedActions / AnticipatedDate
SAR filed / December 11, 2012
Approved by WECC Standards Committee (WSC) / December 19, 2012
Drafting Team Solicited / July 9, 2013
Drafting Team Approved / August 8, 2013
WSC approved posting for 45-Day Comment / March 12, 2014
Posting 1 45-Day Comment Period Open / March 18, 2014
Posting 1 45-Day Comment Period Closes / May 5, 2014
WSC Approval for Posting 2 / July 25, 2014
Posting 2 30-Day Comment Period Open / July 29, 2014
Posting 2 30-Day Comment Period Closes / August 29, 2014

The proposed Variance begins at the YELLOW highlighted section below. The body of the Standard in-between is not subject to Comment.

Background

In the aftermath of large-scale power outages occurring within the Western Interconnection on July 2-3, 1996 and August 10, 1996, President Clinton appointed a “Blue Ribbon” panel to perform a comprehensive assessment of these disturbances and make recommendations to enhance reliability within the Western Interconnection. The investigations culminated in two reports: the “WSCC Disturbance Report for the Power System Outages that Occurred on the Western Interconnection on July 2, 1996 and July 3, 1996,” and “WSCC Disturbance Report for the Power System Outage that Occurred on the Western Interconnection on August 10, 1996” (Disturbance Reports).

The reports indicated, inter alia, that simulation results from dynamic models were inconsistent with measured results. The 1996 disturbance reports required WECC members to provide verified generator data for WECC data files. In 1997, a document was issued to provide guidance regarding how verification could be performed. In 2006, the requirement was memorialized in the Generator Validation Policy (Policy) and associated technical guidelines.

The Policy was last updated by the subject matter experts (SMEs) in 2012. The Policy is currently assigned to the Western Electricity Coordinating Council (WECC) Modeling and Validation Work Group (MVWG) under the auspice of the WECC Technical Study Subcommittee (TSS) /Planning Coordinating Committee (PCC).

Proposed Changes to Create a Variance

The WECC-0101 project is intended to align MOD-26-1 with the existing more stringent polices within WECC, while creating a difference for review between units with digital versus non-digital controls.

The project is targeted to add a Variance to the existing MOD-026-1 to include the following:

  • Changing the Facilities Section at 4.2.2 so that the Variance applies to generation in the Western Interconnection that meets the Bulk-Electric System (BES) definition.
  • Replacing the Effective Date, Section 5.2to reflect a phased in Effective Date that varies for digital and non-digital units. Effective Date, Sections 5.3 and 5.4 would be deleted and replaced accordingly.
  • Replacing Requirement R2.1.1 to include a Requirement that comparison of model responses to recorded responses using staged test data with specific characteristics would be used.
  • Adding E.A.2.1.7.to include verification criteria that includes: 1) data comparison, 2) recordation at specified points, and 3) a specified sampling rate.
  • Replacing Requirement R4 to include a Requirement containing a specified list of features currently used in the WECC but not included in the existing MOD-026-1.
  • Add a new Requirement and associated Measure assigning WECC as the final authority on model selection when parties cannot agree.

Developed as WECC-01011

Standard MOD-26-1 with WECC Variance – Verification of Models and Data for Generator Excitation Control System or Plant Volt / VAR Control Function

A.Introduction

1.Title:Verification of Models and Data forGenerator ExcitationControlSystemor PlantVolt/Var ControlFunctions

2.Number:MOD-026-1

3.Purpose:To verifythat thegenerator excitationcontrolsystem or plantvolt/varcontrolfunction[1]model(includingthepowersystem stabilizer modelandtheimpedancecompensatormodel) and the modelparameters used in dynamic simulationsaccuratelyrepresent the generator excitationcontrolsystem or plant volt/var controlfunctionbehavior when assessing BulkElectric System (BES) reliability.

4.Applicability:

4.1.FunctionalEntities:

4.1.1Generator Owner

4.1.2TransmissionPlanner

4.2.Facilities:

For thepurposeoftherequirementscontained herein, Facilitiesthatare directlyconnected to theBulkElectric System(BES) will becollectivelyreferredas an“applicable unit” thatmeets the following:

4.2.1Generation in the Easternor QuebecInterconnectionswith the followingcharacteristics:

4.2.1.1Individualgeneratingunit greater than 100 MVA (grossnameplaterating).

4.2.1.2Individualgeneratingplant consistingofmultiple generatingunitsthatare directlyconnected at a commonBES buswithtotalgenerationgreater than 100 MVA (grossaggregate nameplaterating).

4.2.2Generation in the WesternInterconnectionwith the followingcharacteristics:

4.2.2.1Individualgeneratingunit greater than 75 MVA (gross nameplaterating).

4.2.2.2Individualgeneratingplant consistingofmultiple generatingunitsthatare directlyconnected at a commonBES buswithtotalgenerationgreater than75MVA (grossaggregatenameplaterating).

4.2.3Generation in the ERCOTInterconnectionwith the followingcharacteristics:

4.2.3.1Individualgeneratingunit greater than 50 MVA (gross nameplaterating).

4.2.3.2Individualgeneratingplant consistingofmultiple generatingunitsthatare directlyconnected at a commonBES buswithtotalgenerationgreater than75MVA (grossaggregatenameplaterating).

4.2.4For allInterconnections:

  • Atechnicallyjustified[2]unit thatmeetsNERCregistrycriteria but isnot otherwise included inthe above Applicabilitysections 4.2.1, 4.2.2,or4.2.3 and is requestedbytheTransmission Planner.

5.Effective Date:

5.1.For Requirements R1, and R3 through R6, thefirst dayofthe firstcalendarquarter beyond the date that this standard is approvedbyapplicableregulatoryauthorities or asotherwise made effective pursuant to the lawsapplicable tosuchERO governmentalauthorities. In thosejurisdictions whereregulatoryapprovalis not required, the standardshall become effective on the firstdayofthefirstcalendar quarter beyond the date this standard is approvedbythe NERCBoard ofTrustees, or asotherwisemade effective pursuant to the lawsapplicable to suchERO governmentalauthorities.

5.2.For Requirement R2, 30 percentofthe entity’sapplicable unit gross MVAforeachInterconnection on the firstdayofthefirstcalendar quarter that is fouryearsfollowingapplicable regulatoryapproval orasotherwise made effective pursuantto the lawsapplicable tosuchERO governmentalauthorities, orin thosejurisdictionswhere no regulatoryapproval is required, on the firstdayofthe firstcalendar quarter that is fouryearsfollowingNERC Board ofTrusteesadoption orasotherwise made effective pursuant to the lawsapplicable to suchEROgovernmentalauthorities.

5.3.For Requirement R2, 50 percentofthe entity’sapplicable unit gross MVAforeachInterconnection on first dayofthe first calendar quarter that is sixyearsfollowingapplicable regulatoryapproval orasotherwise made effective pursuantto the lawsapplicable tosuchERO governmentalauthorities, orin thosejurisdictionswhere no regulatoryapproval is required, on the firstdayofthe firstcalendar quarter that is sixyears followingNERCBoardof Trusteesadoption orasotherwise made effective pursuant to the lawsapplicable to suchEROgovernmentalauthorities.

5.4.For Requirement R2, 100 percentofthe entity’sapplicable unit gross MVAforeachInterconnection on the firstdayofthefirstcalendar quarter that is 10years

followingapplicable regulatoryapproval orasotherwise made effective pursuantto the lawsapplicable tosuchERO governmentalauthorities, orin thosejurisdictionswhere no regulatoryapproval is required, on the firstdayofthe firstcalendar quarter that is 10years followingNERCBoardof Trusteesadoption orasotherwise made effective pursuant to the lawsapplicable to suchEROgovernmentalauthorities.

B.Requirements

R1.EachTransmissionPlanner shallprovide thefollowingrequestedinformation to theGenerator Owner within90 calendar days ofreceivinga writtenrequest : [ViolationRisk Factor:Lower][TimeHorizon:OperationsPlanning]

  • Instructions on howto obtain thelist of excitationcontrolsystem orplant volt/varcontrolfunctionmodelsthatareacceptable to theTransmissionPlanner foruseindynamic simulation,
  • Instructions on howto obtain the dynamic excitationcontrolsystem orplantvolt/var controlfunctionmodel libraryblockdiagramsand/or data sheets formodelsthatare acceptable to the TransmissionPlanner, or
  • Modeldata for anyoftheGenerator Owner’sexistingapplicable unit specificexcitationcontrolsystem or plantvolt/var controlfunctioncontained in theTransmissionPlanner’sdynamic database from the current(in-use) models,includinggenerator MVA base.

R2.EachGenerator Owner shall provide for eachapplicable unit, a verifiedgeneratorexcitationcontrolsystem or plantvolt/var controlfunctionmodel,includingdocumentationanddata(as specified in Part 2.1)to its TransmissionPlanner inaccordance with theperiodicityspecified in MOD-026Attachment 1. [Violation RiskFactor:Medium][Time Horizon:Long-term Planning]

2.1.Eachapplicable unit’smodelshall be verifiedbythe Generator Owner usingoneor more modelsacceptable to the TransmissionPlanner. Verificationforindividual units lessthan20 MVA (grossnameplate rating) ina generatingplant(per Section 4.2.1.2, 4.2.2.2, or4.2.3.2)maybe performed using either individualunit or aggregate unit model(s), orboth.Eachverificationshallinclude thefollowing:

2.1.1.Documentationdemonstratingtheapplicable unit’s modelresponsematches the recorded response for avoltageexcursion fromeither astagedtest ora measured system disturbance,

2.1.2.Manufacturer,model number (if available), and type ofthe excitationcontrolsystemincluding,but not limited to static,ACbrushless,DCrotating, and/orthe plantvolt/var controlfunction(if installed),

2.1.3.Modelstructure and dataincluding, but not limited to reactance, timeconstants,saturationfactors,totalrotationalinertia, or equivalent data forthe generator,

Standard MOD-26-1 with WECC Variance – Verification of Models and Data for Generator Excitation Control System or Plant Volt / VAR Control Function

2.1.4.Modelstructure and datafor the excitationcontrolsystem, includingtheclosed loop voltage regulator ifa closed loop voltageregulator is installedorthe modelstructureand data for theplant volt/var control functionsystem,

2.1.5.Compensationsettings (such asdroop, line drop,differentialcompensation), if used,and

2.1.6.Modelstructure and datafor power systemstabilizer, ifso equipped.

R3.EachGenerator Owner shall provide a written responseto its TransmissionPlannerwithin 90 calendar daysof receivingoneofthefollowingitemsfor anapplicable unit:

  • Writtennotificationfrom its TransmissionPlanner (inaccordance withRequirement R6) that theexcitationcontrolsystem or plantvolt/var controlfunctionmodel is not usable,
  • Writtencommentsfrom its TransmissionPlanner identifyingtechnicalconcernswith the verificationdocumentationrelated to the excitationcontrolsystem or plantvolt/varcontrol functionmodel, or
  • Writtencommentsandsupportingevidencefromits TransmissionPlannerindicatingthat thesimulated excitationcontrolsystem or plantvolt/var controlfunctionmodelresponsedid not match the recordedresponse to atransmissionsystem event.

The written responseshall containeither the technicalbasisfor maintaining the currentmodel, the modelchanges, ora plan to performmodel verification[3](inaccordancewithRequirementR2). [ViolationRisk Factor:Lower][TimeHorizon:OperationsPlanning]

R4.EachGenerator Owner shall provide revised model data or plans to perform modelverification[4](inaccordance withRequirement R2)for anapplicable unit to itsTransmissionPlanner within 180 calendar days ofmakingchanges to the excitationcontrolsystem orplant volt/var controlfunctionthatalter the equipment responsecharacteristic.[5][ViolationRisk Factor:Lower][TimeHorizon:OperationsPlanning]

R5.EachGenerator Owner shall provide a written responseto its TransmissionPlanner,within 90 calendar days followingreceipt ofatechnicallyjustified[6]unit requestfromthe TransmissionPlannerto perform a modelreview ofaunit or plantthat includes oneofthe following: [Violation Risk Factor:Lower][Time Horizon:OperationsPlanning]

  • Details of plans to verifythe model(inaccordancewithRequirementR2), or
  • Correctedmodel dataincludingthesourceof revisedmodeldata suchasdiscoveryofmanufacturer testvalues to replacegeneric modeldata orupdatingofdata parametersbased onanon-site reviewofthe equipment.

R6.EachTransmissionPlanner shallprovide awrittenresponse to the Generator Ownerwithin 90 calendar daysof receivingthe verifiedexcitationcontrolsystem or plantvolt/var controlfunctionmodelinformation in accordancewithRequirement R2 thatthe model is usable (meets the criteria specified inParts 6.1 through 6.3)or is notusable.

6.1.The excitationcontrolsystem or plantvolt/var control functionmodelinitializesto compute modelingdata withouterror,

6.2.A no-disturbance simulationresults in negligible transients,and

6.3.For anotherwise stable simulation, a disturbance simulation results in theexcitationcontrolandplantvolt/var controlfunctionmodel exhibitingpositivedamping.

Ifthe model is not usable, the TransmissionPlanner shallprovide atechnicaldescription ofwhythemodel is not usable. [ViolationRisk Factor:Medium][TimeHorizon:OperationsPlanning]

C.Measures

M1.The Transmission Plannermust have andprovide the datedrequestfor instructions ordata, the transmittedinstructions or data,and dated evidence ofa writtentransmittal(e.g.,electronic mailmessage,postalreceipt, or confirmation of facsimile) asevidencethat it provided the requestwithin 90 calendar days in accordancewithRequirementR1.

M2.The Generator Owner must have andprovide dated evidence it verified each generatorexcitationcontrolsystem or plantvolt/var controlfunctionmodel accordingto Part 2.1for eachapplicable unit and a datedtransmittal(e.g.,electronic mailmessage,postalreceipt, orconfirmationof facsimile)asevidence itprovided the model,documentation,anddatato its TransmissionPlanner, in accordance withRequirementR2.

M3.Evidence for Requirement R3 must include the Generator Owner’s datedwrittenresponse containingthe informationidentified in Requirement R3 and dated evidence

M4.Evidence for Requirement R4 must include,for each ofthe Generator Owner’sapplicable units for which systemchangesspecified in Requirement R4 were made,adatedrevised model dataor plans to perform a modelverificationanddatedevidence(e.g.,electronic mailmessage,postalreceipt, or confirmation of facsimile) it providedthe revisedmodeland dataor planswithin 180 calendar daysofmakingchanges.

M5.Evidence for Requirement R5 must include the Generator Owner’s datedwrittenresponse containingthe informationidentified in Requirement R5 and dated evidence(e.g.,electronic mailmessage,postalreceipt, or confirmation of facsimile) it provideda written response within 90 calendar days followingreceipt ofa technicallyjustifiedrequest.

M6.Evidence of RequirementR6 must include,for eachmodelreceived, thedated responseindicatingthe model wasusable ornot usable accordingto the criteria specified inParts 6.1 through 6.3andfor a modelthat is not usable, a technicaldescription;anddatedevidence of transmittal(e.g.,electronic mail message,postalreceipt,orconfirmation of facsimile) that the Generator Owner wasnotifiedwithin 90 calendardaysof receipt of modelinformation.

D.Compliance

1.Compliance MonitoringProcess

1.1.Compliance Enforcement Authority

The Regional Entityshall serve as theCompliance Enforcement Authorityunlessthe applicable entityis owned, operated, orcontrolledbythe RegionalEntity. Insuchcases theERO oraRegional entityapprovedbyFERC or other applicablegovernmental authorityshall serve as the CEA.

1.2.DataRetention

The followingevidence retentionperiods identifythe period oftime anentityisrequired to retainspecific evidence to demonstrate compliance. For instanceswhere theevidence retention periodspecified belowis shorter than thetimesincethe lastaudit, the Compliance Enforcement Authoritymayaskan entitytoprovide other evidence toshow that it wascompliantfor the full time periodsincethe lastaudit.

The Generator Ownerand TransmissionPlanner shalleach keep data or evidenceto show compliance asidentifiedbelow unlessdirectedbyits ComplianceEnforcement Authoritytoretainspecific evidencefor a longer period oftime aspart of aninvestigation:

  • The Transmission Planner shallretain the information/data requestandprovidedresponseevidence of Requirements R1 and R6, Measures M1 andM6 for threecalendaryearsfrom thedatethedocument wasprovided.

  • The Generator Owner shall retain the latest excitation controlsystem orplantvolt/var controlfunctionmodelverificationevidence of Requirement R2,Measure M2.
  • The Generator Owner shall retain the information/data requestand providedresponse evidence of Requirements R3 throughR5,andMeasures M3 throughM5 for threecalendaryearsfrom thedatethedocument wasprovided.

Ifa Generator Owner orTransmissionPlanner is foundnon-compliant, it shallkeepinformationrelatedto the non-compliance until mitigation is complete orapproved orfor thetimespecified above, whicheveris longer.

The Compliance Enforcement Authorityshall keep the lastauditrecordsand allrequestedandsubmittedsubsequentauditrecords.

1.3.Compliance Monitoring and AssessmentProcesses

Compliance AuditSelf-CertificationSpot Checking

ComplianceInvestigationSelf-ReportingComplaints

1.4.AdditionalCompliance Information

None

[The proposed Variance begins here.]

The following Interconnection-wide Variance shall be applicable in the Western Electricity Coordinating Council (WECC).

E. Regional Variance

E.A.Regional Variance for the Western Electricity Coordinating Council

The Applicability Section 4.2.2 would be replaced in its entirety with the following:

4.Applicability

4.2Facilities

4.2.2Generation in the Western Interconnection meeting the Bulk- Electric System definition.

The Effective Date Section 5 would be replaced in its entirety with the following:

5.Effective Date

The Effective Date of this variance shall be the same as its underlying standard except as follows:

For Requirement R2 applicable to all units::

REPLICATE THE BELOW. NO LONGER AN DIFFERENCE BETWEEN UNITS. CHECK DATES – DO NOT MAKE THE DATES FURTHER OUT THAN THE UNDERLYING STANDARD.

For Requirement R2 applicable only to non-digital units:

5.1For 30% of an entity’s non-digital applicable-unit gross MVA, the Effective Date is the latter of either July 1, 2019, or Applicable Regulatory Approval.

5.2For 50% of an entity’s non-digital applicable-unit gross MVA, the Effective Date is the latter of either July 1, 2020 or Applicable Regulatory Approval.

5.3For 75% of an entity’s non-digital applicable-unit gross MVA, the Effective Date is the latter of either July 1, 2021 or Applicable Regulatory Approval.

5.4For 100% of an entity’s non-digital applicable-unit gross MVA, the Effective Date is the latter of either July 1, 2022 or Applicable Regulatory Approval.

Requirement R2.1.1 would be replaced in its entirety with the following:

E.B.Requirements

E.A.2.1.1Comparison of model responses to recordedresponses using staged test data shall includeterminal voltage, real power, reactive power, and either generator or exciter field voltage or field current.[ViolationRisk Factor:Lower][TimeHorizon:OperationsPlanning]

The following Requirement would be added to Requirement R2:

E.A.2.1.7Verification using disturbance measures shall meet each of the following criteria:[Violation Risk Factor: Lower] [Time Horizon: Operations Planning]

1) Input measured frequency and voltage into the model and then compare measured real and reactive power output to the modeled and real and reactive power output;

2) Measured real and reactive power output and measured frequency and voltage shall both be recorded at either the point of interconnection or the generator’s terminals;

3) Recorded signals shall have a sample rate of 30 samples per second or higher.

Requirement R4 would be replaced in its entirety with the following:

E.A.4Each Generator Owner shall provide to its Transmission Planner revised model and validation data, to include each of the below numbered items, each time a permanent change is made to the operating characteristics of its generator or excitation control system, within 30 days of making that permanent change. [Violation Risk Factor: Lower] [Time Horizon: Operations Planning]

1)Generator open circuit saturation

2)Steady-state generator output power, reactive power, voltage, generator field current and voltage at stated operating point (i.e. V-curves)

3)Inertia

4)Synchronous machine impedances and time constants

5)Automatic Voltage Regulator

6)Power system stabilizer

7)Over-excitation limiter

8)Under-excitation limiter

9)Reactive power compensation

Requirement E.A.7. is added as follows:

E.A.7.WECC, in its role as Reliability Assurer, shall select a single model for use when a Generator Owner and Transmission Planner do not agree to the use of a single model. [Violation Risk Factor: Lower][Time Horizon: Operations Planning]

E.C.Measures

In the Measures Section, the Measure for E.A.2.1.1 and E.A.2.1.7 will be same as Measure M2 in MOD-026-1 R2.1.1.

The Measure for M.E.A.4 would be as follows:

M.E.A.4Each Generator Owner will have evidence that it provided to its Transmission Planner revised model and validation data, to include each of numbered criteria in Requirement E.A.4, each time a permanent change is made to the operating characteristics of its generator or excitation control system, within 30 days of making that permanent change, as required in Requirement E.A.4.

For auditing purposes a permanent change is any alteration in operating characteristics extending beyond 30 days, and specifically excludes changes in operating characteristics resulting during routine maintenance or unique operating circumstances lasting less than 30 days.

Evidence may include, but is not limited to:

  • Dated documentation communicating to the Transmission Planner the operating characteristics existing prior to and after the permanent changes were implemented,
  • Dated documentation communicating to the Transmission Planner the Generator Owner’s plan to leave the changes in place longer than 30 days.

The Measure for M.E.A.7 would be as follows:

M.E.A.7.Where no disagreement in modeling has been raised to WECC, WECC willshow compliance with Requirement R7 by certifying that no such event has occurred. In the alternative, where WECC has been requested by a Generator Owner or Transmission Planner to choose one model as required in Requirement E.A.7, WECC will provide documentation regarding the model selected to include, but not limited to: 1) identification of the parties making the request, 2) the reported reason for the modeling discrepancy, 3) and indication as to which model was selected.

Violation Severity Levels for WECC Variance

E # / LowerVSL / ModerateVSL / High VSL / SevereVSL
E.A.2.1.1 / Same as MOD-026-1 R2.1.1. / Same as MOD-026-1 R2.1.1. / Same as MOD-026-1 R2.1.1. / Same as MOD-026-1 R2.1.1.
E.A.2.1.7 / Same as MOD-026-1 R2.1.1. / Same as MOD-026-1 R2.1.1. / Same as MOD-026-1 R2.1.1. / Same as MOD-026-1 R2.1.1.
E.A.4 / The Generator Owner did not provide all of the data required in E.A.4, on any one occasion. / The Generator Owner did not provide to the Transmission Planner all of the data required in E.A.4 on any two occasions. / The Generator Owner did not provide to the Transmission Planner all of the data required in E.A.4 on any three occasions. / The Generator Owner did not provide to the Transmission Planner all of the data required in E.A.4 on any four or more occasions.
E.A.7 / WECC, as the Reliability Assurer, fails to select the single applicable model upon request from either a generator owner or a Transmission Planner.

4.2ViolationSeverity Levels