Optimizing Power System Restoration Resources and Actions. Electrical and Computer Engineering Iowa State University

Transcription

1 Optimizing Power System Restoration Resources and Actions Chen-Ching Ching Liu Electrical and Computer Engineering Iowa State University PSERC Research Tele-seminar, November 2006

2 State of the Art Primarily manual work by operators Off line restoration planning Little progress has been made on system restoration methodology On line implementation limited Literature 2

3 System Restoration Stages Load restoration is only a means to an end Load restoration is the objective PREPARATION Actions are time-critical SYSTEM RESTORATION LOAD RESTORATION minutes 3-4 hours 3

4 System Restoration Tasks Knowing status of the grid Maximizing generation capabilities with the available black start resources Scheduling of tasks and resources during system restoration Establishing transmission capability and paths while meeting operating constraints Picking up load while meeting operating constraints and load requirements 4

5 Example Restoration Strategies Build-upward upward Build-downward downward Other variations 5

6 First Stage Basic operations common to all strategies Sub-processes defining early stages of restoration process Minimal configuration of autonomous stable source with necessary transmission 6

7 Restoration Building Blocks May include non-autonomous BTG, connection transmission, necessary compensation & load blocks Associated with schedule of switching & control actions 7

8 Second Stage Target System System state achieved by end of restoration process May not be pre-disturbance system Restrict set of post-restoration configurations 8

9 Restoration Constraints Physical constraints Scheduling constraints Policy constraints 9

10 Third Stage Load Restoration Pick Up Loads 10

11 Restoration Strategy SYSTEM RESTORATION LOAD MANAGEMENT MW MANAGEMENT MVAR MANAGEMENT PATH MANAGEMENT STABILITY INSPECTION BLACK-START UNIT OPERATION NON-BLACK-START UNIT OPERATION STATIC MVAR INSPECTION SWITCHING SEQUENCE INSPECTION MECHANICAL INSPECTION FUEL INSPECTION MAN-POWER DISPATCH FAULT INSPECTION CAPACITY INSPECTION TRANSIENT VOLTAGE INSPECTION 11

12 Example Generation Capabilities (4 Different Generating Units) 12

13 Example Optimal Starting MW Sequence 13

14 Cranking Priorities Units with critical maximum interval Critical max interval units with most urgent time constraint Units that can generate highest MWH within a given period 14

15 PECO-Energy Generating Units Unit Type MW Cap. Ramp. rate Crank to paral. Crit. max. int. Crit. min. int. Startup req. (MW) (MW/hr) (hr) (hr) (hr) (MW) Chester_4 CT N/A N/A 0 Chester_5 CT N/A N/A 0 Chester_6 CT N/A N/A 0 Chester_7-9 CT N/A N/A 0 Conowingo_1-7 Hydro N/A N/A 0 Conowingo_8-11 Hydro N/A N/A 0 Cromby_1 Steam :40 N/A N/A 8 Cromby_2 Steam :40 N/A N/A 8 Croydon_1 Ramping CT Rate :30 N/A 5:00 6 Delaware_7 Steam :40 3:20 N/A 5 Delaware_8 Steam :40 3:20 N/A 5 Delaware_9-10 CT N/A N/A 0 Delaware_11-12 CT N/A N/A 0 Eddystone_1 Steam :40 N/A 3:20 12 Eddystone_2 Critical Steam :40 N/A 3:20 12 Min. Interval Eddystone_3 Steam :40 N/A 3:20 12 Eddystone_4 Steam :40 N/A 3:20 12 Eddystone_10 CT N/A N/A 0 Eddystone_20 CT N/A N/A 0 Eddystone_30-40 CT N/A N/A 0 Critical Falls_1-3 Max. CT Interval N/A N/A 0 Moser_1 CT N/A N/A 0 Muddy Run_1-4 Hydro :30 N/A N/A 6.6 Muddy Run_5-8 Hydro :30 N/A N/A 6.6 Richmond_3 CT N/A N/A 0 Richmond_4. CT N/A N/A 0... Schuylkill_1 Steam :00 2:30 N/A 2.7 Schuylkill_3 Steam :00 2:30 N/A 2.7 S h lkill 10 CT N/A N/A 0 Ramping Rate 15

16 MW Capability Curves 16

17 Restoration Strategy with Tie Lines SYSTEM RESTORATION TIE TIE LINE UTILIZATION UTILIZATION LOAD MANAGEMENT BLACK-START UNIT OPERATION MW MANAGEMENT NON-BLACK-START UNIT OPERATION MVAR MANAGEMENT STATIC MVAR INSPECTION PATH MANAGEMENT STABILITY INSPECTION SWITCHING SEQUENCE INSPECTION MECHANICAL INSPECTION FUEL INSPECTION MAN-POWER DISPATCH FAULT INSPECTION CAPACITY INSPECTION TRANSIENT VOLTAGE INSPECTION 17

18 Crank NBS Units System Restoration Check If a Tie Line Can Crank an NBS Unit Check If There Is a Path Between Them Check If Tie Line Can Provide Enough Cranking Power Negotiate for More Power Import Check If Enough Load Can Be Found Negotiate for Less Power Import Tie Line Utilization Load Management MW Management Path Management 18

19 Respond to Request Respond to Tie Line Request System Restoration Check If System Can Provide Enough Power Negotiate for Less Power Export Check Transmission Capacity Decide Priority of Tie Line Check Load Restoration Condition Check NBS Units Restart Condition Tie Line Utilization Load Management MW Management MVAR Management Path Management 19

20 Serve Load Check if a Tie Line Can Serve Loads System Restoration Check if There Are Transmission Paths Check if Tie Line Can Provide Enough Power Negotiate for More power Import Consider Using Tie Line Instead of System Generation Check if Enough Load Can Be Found Negotiate for Less Power Import Tie Line Utilization Load Management MW Management MVAR Management Path Management 20

21 Internal Units to be Cranked by TLi TLi S1 TLe 21

22 Internal Units to Provide TLe - TLi TLi S2 TLe 22

23 Cranking Paths Affected TLi TLe CT S3 23

24 Induced MWh Increase G2 G1 G3 24

25 Tie Line Utilization MWh Increase by S1 Increase from Earlier Startup of S1 Increase Induced by S1 MWh Decrease by S2 (S3) Decrease from Delayed Startup of S2 (S3) Decrease Induced by S2 (S3) 25

26 Test Subsystem CROMBY PEACH BOTTOM MUDDY RUN CONOWINGO 26

27 System Generation Capability MW Min after blackout Without Peach Bottom With Peach Bottom 27

28 System Generation Capability 3500 MW MW MW 10MW 50MW & 100MW From Peach Bottom Min after blackout 28

29 Generic Restoration Actions (GRAs) start_black_start_unit (X) find_path (X,Y) energize_line (X) pick_up_load (X) synchronize (X,Y) connect_tie_line (X) crank_unit (X) energize_busbar (X) 29

30 Using GRAs to Construct RBBs S1 BS NBS B1 B2 B3 C1 L1 C2 L2 C3 30

31 Using GRAs to Construct RBBs Find transmission path between BS & NBS Start black-start unit BS Build transmission path from busbar B1 to B3 and pick up loads for stabilization Crank non-black black-start unit NBS 31

32 Using RBBs & GRAs to Build Restoration Strategies BS1 B1 L1 C1a C1b L3 NBS B2 B3 BS2 C2a C2b L2 C3 32

33 Using RBBs & GRAs to Build Restoration Strategies Select Two RBBs RBB1: Use BS1 to energize B1 RBB2: Use BS2 to energize B2 Build RBB1 Prepare load Start BS unit Energize bus 33

34 Using RBBs & GRAs to Build Restoration Strategies (Cont.) Build RBB2 Energize ring Restart non-black black-start unit NBS Pick up loads along ring 34

35 Petri Net Algorithm to Optimize Sequence of GRAs TL1 Bus1 Line1-2 L1 Line3-1 Bus2 Line2-3 Bus3 L2 L3 35

36 Petri Net Model P1 P2 T1 P8 P14 P15 P3 P9 P4 T14 T2 T3 T4 T5 P22 P21 P17 P16 T15 T16 P25 36

37 Schulykill-Southwark Subsystem 37

38 Time to Complete GRAs Generic Restoration Action (GRA) Restart BSU Energize Busbar from BSU/busbar busbar/line Connect Tie Line Crank a NBSU Synchronize between Busbars/Lines Pick up Load Time (mins( mins.)

39 Sequence of Actions for Schuylkill-Southwark ============================== Time (min.) Actions Restoration Building Block 1: 0 Connect BSU CT10 15 Energize bs2 from CT10 20 Energize bs3 from bs2 25 Energize bs4 from bs3 30 Crank NBSU ST3 from bs4 45 Synchronize ST3 with bs

40 Sequence of Actions for Schuylkill-Southwark ============================== Time (min.) Actions Restoration Building Block 2: 0 Connect BSU CT Energize bs9 from CT Energize bs10 from bs9 25 Energize bs11 from bs10 30 Crank NBSU ST1 from bs11 45 Synchronize ST1 with bs11 40

41 Sequence of Actions for Schuylkill-Southwark Energize bs1 from bs2, bs14 from bs2, bs12 from bs3, bs5 from bs4, bs30 from bs9, bs8 from bs9, bs17 from bs11, bs15 from bs11, bs25 from bs10 70 Energize bs22 from bs1, bs19 from bs14, bs13 from bs12, bs7 from bs5, bs31 from bs39, bs21 from bs25, and synchronize bs14 with bs15 75 Energize bs32 from bs31, bs20 from bs21, bs23 from bs22, and connect bs7 with bs13, bs8 with bs7, and bs22 with w bs21 80 Energize bs24 from bs23, bs26 from bs20 85 Energize bs27 from bs26 90 Energize bs28 from bs

42 Further Information M. M. Adibi (Ed), Power System Restoration Methodologies & Implementation Strategies,, IEEE Press, J. Wu, C. C. Liu, and R. Chu, A A Petri Net Algorithm for Scheduling of Generic Restoration Actions, IEEE Trans. Power Systems,, Feb. 1997, pp L. Fink, K. L. Liou,, and C. C. Liu, From Generic Restoration Actions to Specific Restoration Strategies, IEEE Trans. Power Systems,, May 1995, pp K. L. Liou,, C. C. Liu, and R. Chu, Tie Line Utilization during Power System Restoration, IEEE Trans. Power Systems,, Feb. 1995, pp C. C. Liu, K. L. Liou,, et al., Generation Capability Dispatch for Bulk Power System Restoration A Knowledge-Based Approach, IEEE Trans. Power Systems,, Feb. 1993, pp