Wide-Area Voltage and VAR Control of SCE Transmission Network. i-pcgrid 2014 March 26-28, 2014

Transcription

1 1 Wide-Area Vltage and VAR Cntrl f SCE Transmissin Netwrk i-pcgrid 2014 March 26-28, 2014

2 CONTRIBUTORS SCE Team Frank Ashrafi Armand Salazar Backer Abu-Jaradeh WSU Team Mani Vekatasubramanian Hung Chun Javier Guerrer Xun Zhang 2

3 Intrductin Fr reliable peratin and quality f service t its custmers, a Pwer System needs t emply tw types f cntrls: Lad-Frequency Cntrl, and Vltage Cntrl. In Califrnia, Lad-Frequency Cntrl is dne by CAISO, and Vltage Cntrl is respnsibility f the respective utility cmpanies. SCE s bulk pwer transmissin system (500 kv & 230 kv) vltage cntrl basically is dne manually in accrdance with the SOB 17 and system peratr s experience and preferences. During past decade an autmatic centralized capacitr cntrl (CGCC) has been develped that cntrls capacitrs nly, based n a heuristic cntrl criteria. 3

4 Intrductin (cnt d) With cmplexities that is being impsed n transmissin system, the manual vltage cntrl is nt the apprpriate chice (ptimal) any mre, and certainly will nt satisfy perating requirements at all times. There is als an increased interest in greater pwer system autmatin t relieve peratrs frm repetitive tasks and imprve system quality and utilizatin. Vltage cntrl is a perfect chice fr transmissin system autmatin. 4

5 Intrductin (cnt d) Multi-level hierarchical vltage cntrl f transmissin netwrk is utilized in several Eurpean cuntries, and the accumulated experience is reprted t be highly satisfactry. In general, the cntrl is achieved in three levels: Primary Vltage Cntrl (Gen, SVC, ) Secndary Vltage Cntrl (regins f netwrk) Tertiary Vltage Cntrl (system-wide ptimizatin) 5

6 SCE s Wide-Area Transmissin Vltage Cntrl System The SCE transmissin system vltage cntrller is a tw-level cntrller cnsisting f a Supervisry Central Vltage Crdinatr (SCVC), and a Substatin Lcal Vltage Cntrller (SLVC). The SCVC perfrms an OPF type f calculatins t determine ptimal bus vltage set pints, enables/disables each SLVC, and each SLVC maintains the bus vltage set pints by cntrlling lcal VAR resurces in an ptimal fashin. The cntrl system is aimed at maintaining transmissin vltage prfile at steady state. SCVC serves as a Tertiary Vltage Cntrl element, and SLVC serves as a Secndary Vltage Cntrl element. Primary Cntrl is nt directly activated, but its reactive pwer utput is kept at a minimum s that its full capacity is available during a large disturbance. 6

7 Blck Diagram f Wide-Area Vltage Cntrl in SCE Transmissin Netwrk Wide-area PMU measurements SCADA data State Estimatin mdel Operatr inputs Supervisry Central Vltage Crdinatr (SCVC) Supervisry Cntrl Signals Selected SCADA data Supervisry Cntrl Signals Selected SCADA data Lcal PMUs Substatin #1 Lcal Vltage Cntrller... Substatin #N Lcal Vltage Cntrller Lcal PMUs Switching cmmands SLVC #1 SLVC #N Switching cmmands Substatin #1 Cntrls Substatin #N Cntrls 7

8 Substatin Lcal Vltage Cntrller (SLVC) Maintain substatin bus vltages by switching lcal VAR devices transfrmer banks LTC, capacitr banks and reactr banks. Maintain VAR utput and VAR flw cnstraints. Minimize switching f VAR devices. Alerts and Alarms when getting clse t vltage insecurity. Switching decisins mstly based n lcal PMU measurements bus vltages, VAR flws, equipment status, and equipment limitatins. Supervisry guidance frm central crdinatr vltage schedules, SLVC enable/disable 8

9 SLVC Design Details Slave Mde (Substatin 500 kv SVC in service) Maintain 115 kv and 230 kv bus vltages by switching lcal VAR devices transfrmer banks LTC, capacitr banks and reactr banks Maintain SVC VAR utput within limits and ther VAR flw cnstraints Maintain VAR flw cnstraints Master Mde (500 kv SVC ut f service) Maintain 115 kv, 230 kv and 500 kv bus vltages by switching lcal VAR devices transfrmer banks LTC, capacitr and reactr banks Maintain VAR flw cnstraints Autmatic switching between Master and Slave Mdes using SVC status. Manual verride ptinal. 9

10 SLVC Cntrller Design Cncept Optimal Predictive Cntrller Three predictin methds: Lcal vltage estimatr (LVE) based n n-line reactive pwer flw analysis using lcal PMU data: [ΔQ] = [B][ΔV] Off-line switching estimates (OVE) frm ff-line pwer-flw studies Recent switching analyzer (RSA) frm PMU data analysis f recent switching actins 10

11 SLVC Cntrller Design Cncept Executin Exhaustive search amng candidate cntrl actins Calculate effects due t switching each ne f candidates. Find feasible subset f actins Select candidates that are able t slve the alarm. If nne, select the best candidate amng them. Simple rules fr cntrl pririty specificatin Eliminate lw pririty and high cst candidates. Final selectin f candidate Take actin fr candidate that maintains buses clser t the bus vltage set pints. 11

12 Supervisry Central Vltage Crdinatr (SCVC) Crdinate switching f substatin SLVC cntrllers Enable specific substatin SLVCs as needed Disable ther substatins t prevent hunting Optimize vltage prfile twards minimizing VAR lsses cnvey schedules t substatin SLVCs Optimal management f VAR resurces Alerts and Alarms when getting clse t vltage insecurity 12

13 SCVC Design Details Supervisry Crdinatin Mnitr grid vltage prfile and select ptimal substatin cntrllers t address vltage prblems. Issue Enable/Disable cmmands as needed Mstly based n PMU measurements (assuming sufficient PMU measurements f analg and digital states) Optimal Management Optimize grid vltage prfile t minimize VAR lsses by crdinating substatin vltage schedules Pwer-flw frmulatin runs peridically 13

14 SCVC Design Details Supervisry Crdinatin System-wide vltage estimatr based n n-line reactive pwer flw analysis using wide-area PMU data: [ΔQ] = [B][ΔV] Exhaustive search amng candidate cntrl actins. Find feasible subsets. Simple rules fr cntrl pririty specificatins. Final selectin f candidate 14

15 SCVC Design Details Optimal Management 15

16 Functinal Diagram Wide-Area Vltage Cntrl in SCE Transmissin Netwrk Bulk Pwer Transmissin Netwrk Other Synchrphasr Applicatins PDC Operatr Cntrl Netwrk Mdel Central Crdinatr Operatr Cntrl Lcal Cntrller LTC CT1 PT1 500kV r 230kV sub. CT2 Optimal Reactive Pwer flw Measurements Crdinatr Other SLVCs PT2 16

17 Cntrl Blck Diagram Wide-Area Vltage Cntrl in SCE Transmissin Netwrk 17

18 Preliminary RTDS Test 500 Reactive pwer lad used t test the cntrller Reactive Lad (MVAR) Lad

19 Preliminary RTDS Test Master Mde (SVC Out-Of-Service) 500kV Vltage Vltage (kv) Cntrlled Uncntrlled Time 19

20 Preliminary RTDS Test 236 Master Mde (SVC Out-Of-Service) 230kV Vltage 234 Vltage (kv) Uncntrlled Cntrlled Time 20

21 Preliminary RTDS Test 118 Master Mde (SVC Out-Of-Service) 115kV Vltage 117 Vltage (kv) Uncntrlled Cntrlled Time 21

22 Preliminary RTDS Test Slave Mde (SVC in service) SVC Reactive Pwer Output 390 Reactive pwer (MVAR) Uncntrlled Cntrlled Time 22

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