Voltage Stability IROL Monitoring

Transcription

1 Vltage Stability IROL Mnitring RC Users Grup April 11, 2017 Tny Burt Saad Malik

2 Purpse IROL Mnitring IROL Prcedures Insight int Peak RTVSA tl Lessns Learned Cntinuus Imprvement 2

3 IROLs in Peak s Ftprint Tw areas where Intercnnectin Reliability Operating Limits (IROL) have been identified: NW Washingtn (Puget Sund) San Dieg area imprt Real-Time Vltage Stability Analysis (RTVSA) Tl t calculate limit IROL Prcedures Margins t initiate actin are in place t ensure that a single cntingency des nt immediately cause an exceedance f the IROL 4 levels f alarms - Allws time t crdinate and implement mitigatin prir t exceeding the IROL 3

4 IRO Standards IRO Reliability Crdinatr Actins t Operate Within IROLs R1.-Fr each IROL (in its Reliability Crdinatr Area) that the Reliability Crdinatr identifies ne r mre days prir t the current day, the Reliability Crdinatr shall have ne r mre Operating Prcesses, Prcedures, r Plans that identify actins the Reliability Crdinatr shall take r actins the Reliability Crdinatr shall direct thers t take (up t and including lad shedding): 1.1. That can be implemented in time t prevent the identified IROL exceedance 1.2. T mitigate the magnitude and duratin f an IROL exceedance such that the IROL exceedance is relieved within the IROL s Tv 4

5 IRO Standards IRO Cnt. R2.-Each Reliability Crdinatr shall initiate ne r mre Operating Prcesses, Prcedures, r Plans (nt limited t the Operating Prcesses, Prcedures, r Plans develped fr Requirement R1) that are intended t prevent an IROL exceedance, as identified in the Reliability Crdinatr s Real-time mnitring r Real-time Assessment. R3. Each Reliability Crdinatr shall act r direct thers t act s that the magnitude and duratin f an IROL exceedance is mitigated within the IROL s Tv, as identified in the Reliability Crdinatr s Real-time mnitring r Real-time Assessment 5

6 IROL Mitigatin Philsphy When an IROL is exceeded, the next cntingency can cause instability, uncntrlled separatin r cascading utages that adversely impact the reliability f the Intercnnectin. All available mitigating ptins will be evaluated t prevent the exceedance f an IROL up t and including lad shed (IRO R1.1) 6 Prcedures are crdinated/cllabrated with affected entities prir t implementatin Crdinated studies Identify Generatin (lcatin, effectiveness, etc.) Identify shunt devices that are effective t mitigate Identify lad t be shed if necessary (including time frame necessary t implement)

7 Vltage Stability Prblem Large lad pckets Remte generatin Lack f VAR margins within the lad bubble Lack f VAR margins n the surce side (r at interface) 7

8 IROL Mnitring 8 What limits qualify as an IROL Is there risk t instability r cascading? Is the risk wide-spread? In real-time peratins, d we anticipate appraching the pint f cllapse r cascading? Cntinuus studies t analyze a need fr ther IROLs Cntinually assess need fr IROLs A limit may n lnger be an IROL after system imprvements

9 VSA Apprach Perfrm seasnal studies Calculate seasnal limits Shrtcmings in seasnal study apprach Use RTVSA 9

10 Peak RTVSA Tl SE Case.csv EMS RAS Arming Pints VSA (POM/ROSE) Alarms Output Data Client Archive 10

11 Mdes f Operatin Offline Mde Operatinal Planning Analysis Real-time Operatins Supprt Other Studies Real-time Mde Utilizes SE case Real-time RAS statuses 11

12 Simulatin Assumptins Scenari Definitin 12 Surce Sink Interface Cntingencies Buses t mnitr Alarm Threshlds Criteria N pwer-flw slutin

13 Inputs/Outputs Inputs 13 SE Case RAS Arming Pints RAS Scripts Outputs PV Curves QV Curves Interface Limits Display Client Alarm Outputs

14 PV Analysis Example fr Bus ABC Base-case Cntingency A Vltage (pu) Last Healthy Step (calculate VAR margin) Interface Limit Interface Flw (MW) 14

15 Prs and Cns f RTVSA Prs Using real-time system cnditins Mre accurate tplgy Early detectin & alarming Cns Instability is determined by n slve pwerflw Tplgy issues SE slutin quality issues 15

16 RTVSA Limit Limit Interface Flw 16

17 Cnsideratins fr RTVSA Bus-branch mdel vs. nde-breaker mdel Rigrus testing: Unit capability curves Shunt switching Lad scaling assumptins RAS Mdeling Real-time measurements 17

18 RTVSA Apprach PV Analysis What is the limit? Impact f simulatin assumptins t the limit Which surces t cnsider Which cntingencies t mdel What shuld be RAS assumptins Generatr t lad stressing vs. Generatr t Generatr stressing 18

19 RTVSA Apprach (Cntd.) QV Analysis Calculating VAR margins at last healthy step in simulatin 19

20 Mnitring Cnsideratins Hw ften limit shuld be calculated Type f infrmatin peratrs need t see: Limiting cntingency Limiting bus VAR margins Impact f SE Case t Limit 20

21 Lessns Learned (Tl Perspective) Reading full tplgy mdel was the right thing Applying RAS schemes was challenging Real-time vs. Operatins Planning Allw greater time fr parallel peratin Cntinual review and dcumentatin f assumptins 21

22 Lessns Learned frm IROL Management Output f the RTVSA tl cnsidered as the IROL autmatically Imprtance f validatin tls Use f a different tl Validatin cnsideratins Operating margins fr validatin and crdinatin 22

23 Cntinuus Imprvements Use f phasr data Better prcesses fr defining lad pckets t mnitr RAS Enhancements fr OPA Autmatic validatin f RTVSA results Multi-dimensinal Transfers 23

24 IROL Mitigatin Prcedures NW Washingtn 1 st alarm MW margin Studies by ROE t validate limit Cnference call with Impacted entities Insert available shunt devices/ Operate twards high end f vltage schedules Evaluate ACEs ROE evaluate IROL at least nce an hur San Dieg Imprt Limit 1 st alarm- 800 MW margin Studies by ROE t validate limit Cnference call with impacted entities Insert available shunt devices/ Operate twards high end f vltage schedules (NW) ROE evaluate Limit at least nce every hur 24

25 IROL Mitigatin Prcedures NW Washingtn 2 nd Alarm - < 500MW margin (NW) Further validatin f the limit Cnference call with impacted entities Operating phase shifters Bring n all available generatin Curtail interruptible lads San Dieg Imprt Limit 2 nd Alarm - < 500MW margin (SW) Further validatin f the limit Cnference call with impacted entities Insert available shunt devices Evaluate limit at least nce every 30 minutes Synchrnus cndensers t increase the limit 25

26 IROL Mitigatin Prcedures NW Washingtn 3 rd Alarm- < 250 MW margin Further validatin f the limit Cnference call with impacted entities Cntinue t increase generatin EEAs Pssible curtailment f firm schedules Evaluate limit at least every 15 minutes San Dieg Imprt Limit 3 rd Alarm- < 200 MW margin Further validatin f the limit Cnference call with affected entities Operatin f shunt devices Generatin re-dispatch Evaluate limit at least every 15 min 26

27 IROL Mitigatin Prcedures If IROL exceedance is imminent: If all mitigating actins have been exhausted & IROL exceedance is still imminent, direct entities t shed lad t prevent exceeding the IROL Nt necessary t shed lad t prevent a mmentary exceedance if ther mitigating actins are still taking place. 27

28 IROL Mitigatin Prcedures 4 th Alarm- IROL in exceedance Cntact entities t cnfirm mitigating actins taking place Evaluate where further mitigating actin can be taken Direct lad shed if ther mitigating actins being taken are nt apprpriate r will nt relieve the exceedance within 30 minutes. 28

29 Questins