Composite Load Model Sensitivity Study

Transcription

1 Composite Load Model Sensitivity Study An Analysis of the Sensitivity of WECC Grid Planning Models to Assumptions Regarding the Composition of Loads NERC LMTF Meeting Salt Lake City, UT January 12, 2016 Scott Ghiocel, Nick Tenza Mitsubishi Electric Power Products, Inc. (MEPPI) Power System Engineering Services Department Warrendale, Pennsylvania

2 Background Objectives Explore the sensitivity of planning models to uncertainty in the composition and behavior of loads Provide guidance for future planning studies and data collection Transmission Providers: PacifiCorp, PG&E, SCE, and SRP Tasks Develop list of parametric simulations to be conducted Investigate sensitivities of the parameter list Run all contingencies for each transmission provider (TP) Monitor all transmission bus voltages in each TP area Monitor generation for loss of synchronism or excessive oscillation Detailed analysis for specific parameters and cases High-sensitivity parameters Stressed base case 2

3 Composite Load Model in WECC Load Bus System Bus (230, 115, 69kV) Low-side Bus M Motor A M Motor B M Motor C M Motor D UVLS UFLS Electronic Static

4 Study Work Sensitivity analysis procedure: Phase 1 Base Case: Motor D stalling disabled Phase 2 Base Case: Enable Motor D stalling (Tstall = sec) Vary one parameter in the Phase 2 Base Case Two new cases: parameter set to minimum and maximum values Total load is unchanged (same power flow case) Results: Identify study thresholds and flag observations Compute sensitivities with respect to Phase 2 Base Case Grouped by observation type Percent change in number of observations Heat maps to quickly identify key parameters and contingencies Results summarized by parameter Detailed results for each contingency 4

5 Study Criteria (Thresholds) Transient voltage dips will be monitored and recorded for dips that exceed: 25% at load buses and 30% at non-load buses 20% for more than 20 cycles at load buses Frequency oscillations will be monitored and recorded for dips below 59.6 Hz for 6 cycles or more at load buses Post-transient voltage deviations exceeding 5% at any bus Voltage recovery to 70% in 1 second, 80% in 3 seconds, 90% in 5 seconds Power, angle, or voltage magnitude oscillations will be monitored and recorded for 5% damping from the first swing peak to the 3 rd swing peak Voltage overshoot will be monitored Voltage greater than 1.1 p.u, or greater than 1.05 p.u. for 5 seconds or longer. Any non-consequential load loss (total load loss to be calculated) Any generator that loses synchronism Damping ratio sensitivities (stressed cases) 5

6 Parameter Values for Motor D Part 1 Ref. No. Description of Parameter Phase 1 Base Value as given in dyd/dyr Phase 2 Minimum Value Maximum Value 1 Vstall, Stall voltage, p.u Tstall, Stall time delay, sec Vc1off, Contactor voltage at which tripping starts, p.u Vc2off, Contactor voltage at which tripping is complete, p.u Vc1on, Contactor voltage at which reconnection is complete, p.u Vc2on, Contactor voltage at which reconnection starts, p.u Tth, Motor D thermal time constant, sec Th1t, Motor D thermal protection trip start level, p.u. temperature Th2t, Motor D thermal protection trip completion level, p.u. temperature FmA, Motor A fraction of load P % +20% 11 FmB, Motor B fraction of load P % +20% 12 FmC, Motor C fraction of load P % +20% 13 FmD, Motor D fraction of load P % +20% 14 Fel, Electronic load fraction of P % +20% 15 Vtr1, First under voltage trip level, p.u Ttr1, First under voltage trip delay time, sec Fuvr, Fraction of load with under voltage relay protection Frst, Fraction of load that can restart after stalling Vrst, Voltage at which restart can occur, p.u Trst, Restart time delay Notes: 1. Contactor settings (Vc1off, Vc2off, Vc1on, Vc2on) are changed simultaneously. 2. Motor fraction (FmA, FmB, FmC, FmD) base values are examples. Load fractions vary from load to load in the base case. 6

7 Parameter Values for Motor D Part 2 Ref. No. Description of Motor D Parameter Base Value as given in dyd/dyr Phase 2 Value 1 Value 2 Value 3 Value 4 1 Vstall, Stall voltage, p.u Tstall, Stall time delay, sec Vc1off, Contactor voltage at which tripping starts, p.u Vc2off, Contactor voltage at which tripping is complete, p.u Vc1on Contactor voltage at which reconnection is complete (pu) Vc2on Contactor voltage at which reconnection starts (pu) Tth, Motor D thermal time constant, sec Th1t, Motor D thermal protection trip start level, p.u. temperature Th2t, Motor D thermal protection trip completion level, p.u. temperature FmD, Motor D fraction of load P % -10% +10% +40% 11 Fuvr, Fraction of load with under voltage relay protection Vrst, Voltage at which restart can occur, p.u Note: Contactor settings changed as a group. 7

8 Sensitivity Analysis Part 1: Motor D key parameters All contingencies with min/max parameter values Contingency screening Based on total observations and load loss Included specific contingencies as requested Geographic diversity Part 2: Motors A, B, C, and additional values for Motor D Stressed base case with selected contingencies Parameter variations for Motors A, B, and C, additional values for Motor D 8

9 Study Work Simulations in PSS/E or PSLF, depending on each TP For both PSS/E and PSLF: Start with base case Change parameter value in the DYR or DYD file Monitor all bus voltages at 69 kv or above Post-processing and analysis using Python Generally, most composite load model parameters are the same for all loads Some exceptions: motor fractions (FmA, FmB, FmC, FmD, etc.) Other parameter values that differ have few variations 9

10 Preliminary Results Motor D Observed similar results for all sets of data (SRP, SCE, PG&E, PacifiCorp) Important parameters for Motor D were identified for all four utilities studied: Tstall and Vstall (Motor D stall parameters) Vc1on/Vc2on and Vc1off/Vc2off (Motor D contactor) FmD (fraction of Motor D load) Tth, Th1t, and Th2t (thermal relay time constant and thresholds) Fuvr (fraction of Motor D load with undervoltage relays) Vrst (voltage at which of Motor D load restarts) 10

11 FmD (Voltages) 11

12 Tstall (Voltages) 12

13 Tth (Voltages) 13

14 Heat Maps Phase 2 Base Case Ref. No. Variable Setting > 25% Voltage Dip > 30% Voltage Dip Generator Swings Offline Observations Voltage overshoot over 1.1 Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage Deviation > 5% p.u. b/w 15 and 30 seconds Voltage overshoot over 1.1 p.u. b/w 8 and 15 seconds Type of observation Voltage overshoot over 1.1 p.u. within 8 seconds Parameters 1 Phase % % % 61-9% % % % 40-82% 20-89% 328-9% 88-16% 3-20% % % 68 1% % 340 6% % % 70-61% 385 7% 98-7% 4 FmD -10% % % 68 1% % 342 7% % % % 390 8% 96-9% 5 (varies) +10% % % 79 18% % % % % % 390 8% 111 6% 6 +20% % % 82 22% % % % % % % % 7 +40% % % 88 31% % % % % % 373 3% 114 9% % % 71 6% % % % 225 2% 196 8% 371 3% 96-9% % % 70 4% 190 7% 342 7% % 222 0% 193 7% 383 6% 101-4% 10 Fuvr % % 67 0% 177-1% 321 0% % 215-3% 188 4% 358-1% 108 3% 11 (0.1) % % 67 0% 192 8% 342 7% % 213-4% 169-7% 366 1% % % % 68 1% 177-1% 337 5% % 207-6% % 386 7% % % % 79 18% % % % 237 7% 36-80% % % % % 70 4% 178 0% 320 0% 683-4% 219-1% 177-2% 361 0% 105 0% % % 69 3% 178 0% 320 0% 709 0% 219-1% 191 6% 361 0% 105 0% 16 Th1t % % 67 0% 178 0% 320 0% 712 0% 219-1% 191 6% 361 0% 105 0% 17 (0.7) % % 68 1% 178 0% 320 0% 712 0% 222 0% 184 2% 361 0% 105 0% % % 69 3% 178 0% 320 0% 712 0% 219-1% 182 1% 361 0% 105 0% % % 69 3% 178 0% 320 0% 712 0% 204-8% 183 1% 361 0% 105 0% % change from Base Case for all contingencies (Motor D fraction) % % 75 12% 178 0% 320 0% 708-1% 237 7% % % 105 0% % % 74 10% 178 0% 320 0% 709 0% 233 5% % % 105 0% 22 Th2t % % 70 4% 178 0% 320 0% 712 0% 217-2% % 361 0% 105 0% 23 (1.2) % % 70 4% 178 0% 320 0% 712 0% 220 0% % 361 0% 105 0% % % 68 1% 178 0% 320 0% 712 0% 222 0% 164-9% 361 0% 105 0% % % 71 6% 178 0% 320 0% 712 0% 202-9% 67-63% 358-1% 105 0% % % 85 27% % % % % % 384 6% 83-21% % % 61-9% 173-3% % % 38-83% 21-88% % % 28 Tstall % % 61-9% 164-8% % % 39-82% 21-88% % % 29 (0.033) % % 61-9% 183 3% % % 38-83% 21-88% % % % % 60-10% 191 7% % % 38-83% 21-88% % % % % 60-10% 191 7% % % 38-83% 21-88% % % % % 76 13% 178 0% 320 0% 687-4% 236 7% % % 107 2% % % 72 7% 178 0% 320 0% 698-2% 221 0% % 378 5% 105 0% 34 Tth % % 70 4% 178 0% 320 0% 709 0% 221 0% % 361 0% 105 0% 35 (15) % % 69 3% 178 0% 320 0% 712 0% 216-2% % 361 0% 105 0% % % 71 6% 178 0% 320 0% 712 0% 202-9% % 361 0% 105 0% % % 73 9% 178 0% 320 0% 712 0% 203-8% 96-47% 358-1% 105 0% 38 Min % % 84 25% % % % % % 362 0% 104-1% 39 R % % 66-1% % % % 223 1% % % 100-5% 40 R % % 66-1% % % % 223 1% % % 100-5% Vc1Vc2 41 R % % 64-4% % 338 6% % % % 393 9% 104-1% 42 R % % 65-3% % % % % 50-72% % % 43 Max % % 67 0% % 319 0% 664-7% % % % 72-31% % % 66-1% 178 0% % % % % 380 5% 114 9% % % 66-1% 178 0% 315-2% 751 5% % % 361 0% 112 7% 46 Vrst % % 66-1% 178 0% 320 0% 714 0% % % 361 0% 108 3% 47 (0.95) % % 66-1% 178 0% 320 0% 712 0% 207-6% % 361 0% 105 0% % % 67 0% 178 0% 320 0% 712 0% 215-3% 167-8% 361 0% 105 0% % % 66-1% 178 0% 320 0% 712 0% 219-1% 195 8% 361 0% 105 0% % % 66-1% 173-3% % % 40-82% 21-88% % % % % 66-1% 170-4% % % 39-82% 18-90% % % 52 Vstall % % 72 7% 167-6% 299-7% % % 40-78% % % 53 (0.5) % % 71 6% 189 6% 326 2% % 220 0% 194 7% 353-2% 101-4% % % 80 19% 194 9% % % % % 365 1% 86-18% % % 73 9% % % % % % 7-98% 56-47% 14

15 Sensitivity Results Utility A (1) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Notes: 1. Phase 2 base case values are shown in parentheses under each parameter. Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u. 1 Base % 22-72% 946-6% % % Fel 3 20% % % % % 4-20% 19-76% % % % Fma 5 20% % % % % 6-20% 20-74% % % % Fmb 7 20% % % % % 8-20% 22-72% % % % Fmc 9 20% % % % % 10-20% 19-76% % % % Fmd 11 20% % % % % 12 Frst % % % % 13 (0.2) % % % % 14 Fuvr % % % % 15 (0.1) % 27-97% 66-99% % 16 Th1t % % % % 17 (0.7) % % % % 18 Th2t % % % % 19 (1.2) % % % % 15

16 Sensitivity Results Utility A (2) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u. 20 Trst % % % % 21 (0.3) % % % % 22 Tstall % 27-97% 62-99% % 23 (0.033) % % % % 24 Tth % % % % 25 (15) % % % % 26 Ttr % % % % 27 (0.02) % % % % 28 Vc1Vc % % % % 29 (0.5) % % % % 30 Vrst % % % % 31 (0.95) % % % % 32 Vstall % 27-97% % % 33 (0.5) % % % % 34 Vtr % % % % 35 (0.6) % 999-1% % % Notes: 1. Phase 2 base case values are shown in parentheses under each parameter. 2. Contactor settings (Vc1off, Vc2off, Vc1on, Vc2on) are changed simultaneously. (Ref. No. 28 and 29) 16

17 Sensitivity Results Utility B (1) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u. 1 Base % % % % % Fel 3 20% % % % % 4-20% % % % % FmA 5 20% % % % % 6-20% % % % % FmB 7 20% % % % % 8-20% % % % % FmC 9 20% % % % % 10-20% % % % % FmD 11 20% % % % % % % % % Frst % % % % % % % % Fuvr % % % % % % % % Th1t % % % % % % % % Th2t % % % % Notes: 1. Phase 2 base case values are shown in parentheses under each parameter. 17

18 Sensitivity Results Utility B (2) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u % % % % Trst % % % % % % % % Tstall % % % % % % % % Tth % % % % % % % % Ttr % % % % 28 Max % % % % Vc1Vc2 29 Min % % % % % % % % Vrst % % % % % % % % Vstall % % % % % % % % Vtr % % % % Notes: 1. Phase 2 base case values are shown in parentheses under each parameter. 2. Contactor settings (Vc1off, Vc2off, Vc1on, Vc2on) are changed simultaneously. (Ref. No. 28 and 29) 18

19 Sensitivity Results Utility C (1) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Notes: 1. Phase 2 base case values are shown in parentheses under each parameter. Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u. 1 Phase % % % % % Fel 3 20% % % % % 4-20% % % % % FmA 5 20% % % % % 6-20% % % % % FmB 7 20% % % % % 8-20% % % % % FmC 9 20% % % % % 10-20% % % % % FmD 11 20% % % % % 12 Frst % % % % 13 (0.2) % % % % 14 Fuvr % % % % 15 (0.1) % % % % 16 Th1t % % % % 17 (0.7) % % % % 18 Th2t % % % % 19 (1.2) % % % % 19

20 Sensitivity Results Utility C (2) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u. 20 Trst % % % % 21 (0.3) % % % % 22 Tstall % % 59-98% % 23 (0.033) % % % % 24 Tth % % % % 25 (15) % % % % 26 Ttr % % % % 27 (0.02) % % % % 28 Vc1off Max % % % % 29 (0.5) Min % % % % 30 Vrst % % % % 31 (0.95) % % % % 32 Vstall % % % % 33 (0.5) % % % % 34 Vtr % % % % 35 (0.6) % % % % Notes: 1. Phase 2 base case values are shown in parentheses under each parameter. 2. Contactor settings (Vc1off, Vc2off, Vc1on, Vc2on) are changed simultaneously. (Ref. No. 28 and 29) 20

21 Sensitivity Results Utility D (1) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage Deviation > 5% Voltage overshoot over 1.1 p.u. 1 Phase % 368 0% % % % Fel 3 20% 364-1% % % % 4-20% 368 0% % % % FmA 5 20% 360-2% % % % 6-20% 373 1% % % % FmB 7 20% 355-4% % % % 8-20% 371 1% % % % FmC 9 20% 389 6% % % % 10-20% 342-7% % % % FmD 11 20% % % % % 12 Frst % % % % 13 (0.2) % % % % 14 Fuvr % % % % 15 (0.1) % % % % 16 Th1t % % % % 17 (0.7) % % % % 18 Th2t % % % % 19 (1.2) % % % % 21

22 Sensitivity Results Utility D (2) Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage Deviation > 5% Voltage overshoot over 1.1 p.u. 20 Trst % % % % 21 (0.3) % % % % 22 Tstall % % % % 23 (0.033) % % % % 24 Tth % % % % 25 (15) % % % % 26 Ttr % % % % 27 (0.02) % % % % 28 Vc1off % % % % 29 (0.5) % % % % 30 Vrst % % % % 31 (0.95) % % % % 32 Vstall % % % % 33 (0.5) % % % % 34 Vtr % % % % 35 (0.6) % % % % 22

23 Detailed Sensitivity Results Motor D Ref. No. Variable Setting Generator Swings Offline Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage Deviation > 5% 1 Phase % 61-9% % % % 40-82% 3-20% 68 1% % 340 6% % % 4 FmD -10% 68 1% % 342 7% % % 5 (varies) +10% 79 18% % % % % 6 +20% 82 22% % % % % 7 +40% 88 31% % % % % % % % % 225 2% % 190 7% 342 7% % 222 0% 10 Fuvr % 177-1% 321 0% % 215-3% 11 (0.1) % 192 8% 342 7% % 213-4% % 177-1% 337 5% % 207-6% % % % % 237 7% % 178 0% 320 0% 683-4% 219-1% % 178 0% 320 0% 709 0% 219-1% 16 Th1t % 178 0% 320 0% 712 0% 219-1% 17 (0.7) % 178 0% 320 0% 712 0% 222 0% % 178 0% 320 0% 712 0% 219-1% % 178 0% 320 0% 712 0% 204-8% % 178 0% 320 0% 708-1% 237 7% % 178 0% 320 0% 709 0% 233 5% 22 Th2t % 178 0% 320 0% 712 0% 217-2% 23 (1.2) % 178 0% 320 0% 712 0% 220 0% % 178 0% 320 0% 712 0% 222 0% % 178 0% 320 0% 712 0% 202-9% % % % % % % 173-3% % % 38-83% 28 Tstall % 164-8% % % 39-82% 29 (0.033) % 183 3% % % 38-83% % 191 7% % % 38-83% % 191 7% % % 38-83% 23

24 Detailed Sensitivity Results Motor A Ref. No. Variable Setting Voltage < 70% in 1 second Voltage < 80% in 3 seconds Voltage < 90% in 5 seconds Voltage overshoot over 1.1 p.u. b/w 15 and 30 seconds Voltage overshoot over 1.1 p.u. b/w 8 and 15 seconds Voltage overshoot over 1.1 p.u. within 8 seconds 1 Phase % 336 5% % % 334-7% % 11 H % 330 3% 779 9% 197 9% 359-1% 109 4% 12 (0.1) % 313-2% 649-9% % % 91-13% % 315-2% 735 3% 78-57% % % % 308-4% % % 384 6% 110 5% 15 Ls % % % % 343-5% % 16 (1.8) % 332 4% % 166-8% 387 7% 98-7% % % % % 388 7% 88-16% % 331 3% 758 6% % 363 1% 86-18% 19 Tpo % 328 2% 713 0% % 361 0% 90-14% 20 (0.095) % 323 1% % 171-6% 360 0% 106 1% % 320 0% 661-7% 169-7% 358-1% 107 2% % 326 2% 728 2% 40-78% % 73-30% 23 Trc % 329 3% 770 8% 41-77% % 75-29% 24 (9999) % 326 2% 766 8% 44-76% % 77-27% % 322 1% 703-1% 39-78% % 86-18% % 337 5% 717 1% % 377 4% 100-5% 31 Ttr1 (0) % 329 3% 757 6% % 357-1% 103-2% % % % 165-9% 383 6% 78-26% % 334 4% % 43-76% 364 1% 84-20% 45 Vtr % 330 3% % 55-70% 373 3% 91-13% 46 (0.7) % 319 0% 746 5% % 369 2% 101-4% % 304-5% 738 4% % % % 24

25 Load Loss Summary Per Contingency Ref. No. Variable Setting Contingency 1 Contingency 2 Contingency 3 Load Loss (MW) 1PH Stuck Breaker 5+ branches lost Load Loss (MW) Load Loss (MW) Contingency 4 Contingency 5 Load Loss (MW) Load Loss (MW) 1 Phase % % 490-8% 261-3% % % 3-20% % 512-4% 266-2% % % 4 FmD -10% % 523-2% 268-1% % % 5 (varies) +10% % 542 2% 272 1% % % 6 +20% % 552 4% 273 1% % % 7 +40% % 569 7% 276 2% % % % 533 0% 270 0% % % % 533 0% 270 0% % % 10 Fuvr % 533 0% 270 0% % % 11 (0.1) % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % 28 Tstall % 533 0% 270 0% % % 29 (0.033) % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % 34 Tth % 533 0% 270 0% % % 35 (15) % 533 0% 270 0% % % % 533 0% 270 0% % % % 533 0% 270 0% % % No-fault gen loss No-fault gen loss Line and gen loss Double line loss 25

26 Fast Tripping of Stalled Motor D Load Main idea for Motor D load Detect the stall condition and trip early (< 1 sec) instead of waiting for the thermal relay to trip (10+ sec)? Functionality is not included in the composite load model Change thermal time constant (Tth) from 15 seconds to 0.5 seconds Sensitivity analysis for the Tth parameter Tth values: 0.5, 5, 10, and 15 sec 2 contingencies in the SCE area (500 kv line outage and double line outage) 8 bus voltages plotted at the 230 kv and 500 kv voltage level Result Setting Tth = 0.5 sec results in large amounts of motor load tripping, leading to significant overvoltages Steady-state overvoltage is nearly the same for all parameter values 26

27 Fast Motor D Tripping (1)

28 Fast Motor D Tripping (2)

29 Fast Motor D Tripping (3)

30 Fast Motor D Tripping (4)

31 Fast Motor D Tripping (5)

32 Fast Motor D Tripping (6)

33 Other Observations Switching behavior can cause hunting Example: Motor D contactors with a high setpoint Switching occurs every time step (no time constant or limit) 33

34 Expected Outcomes of the Study Better understanding of how the composite load model parameters affect planning studies System response to different types of contingencies How each parameter affects different portions of the voltage response Guidance for model users on setting or changing parameter values Can be helpful for model validation and benchmarking to measurement data More information for future model updates and software development Identification of important and unimportant parameters Public report to be issued at completion of the project 34