Transient Stability Analysis Tool (TSAT) Update April 11, Hongming Zhang EMS Network Applications Manager

Transcription

1 Transient Stability Analysis Tool (TSAT) Update April 11, 2016 Hongming Zhang EMS Network Applications Manager

2 Agenda Peak Online TSAT Introduction: Where we are on Wide-wide System Model (WSM) -TSAT online Implementation TSAT Use Cases and Identified Hurdles Next Steps 2

3 Peak TSAT Use Cases Overview 3 Peak implemented online TSAT tool with the WSM for Dynamic limit assessment of WECC Paths limited by transient stability concerns Monitoring system frequency deviation under critical contingencies in consideration of RAS generation drop interaction High renewable generation penetration System model validation-mod033 using PMU Fast voltage collapse risk monitoring

4 Peak Online TSAT Architecture Contingency Data Monitor Data Online TSAT Stability Results Archive Files EMS Powerflow Cases PTI 30 RAW File with EMS Label TSAT Engine PI Historian Stability Limit Archive Files Dynamic Data Dynamic Model (GEN, PSS, GOV, etc) RAS Model Data and HVDC 4

5 5 Peak Online TSAT UI: Operator View

6 Peak TSAT Implementation Highlight 8 Servers (4 Production and 4 Test) are running at 15 min cycle to solve 6 transfer scenarios, 92 contingencies active WSM units with 95% total generation capacity mapped to *.dyd file by EMS label Enhanced the software by custom features Started to validate TSAT model & solutions Target for parallel operation trial in

7 Use Case 1: Dynamic Limit Assessment Started validating TSAT limits against realtime measurements via ICCP Benchmark with CAISO TSAT tool results 7

8 TSAT Limit Results Analysis* Limiting Reason Number Assignment 8 Limiting Reason Limiting Reason Explanation Number of Limiting Reason Appeared Percentage 50 LR_Drop Volt. Drop % 25 LR_FrqDrp Freq. Drop % 75 LR_Marg Stability Margin % 100 LR_STAT Volt. Collapse % Total % *Results covers two weeks validation study period. Nearly 90% of TSAT Limits determined by two limiting contingencies.

9 Hurdle for TSAT Limits Validation Lack of real-time transient stability limit study criteria authorized by NERC or WECC 9 TSAT limits vary with different criteria applied Look for team-up for agreed RT TSAT criteria

10 Use Case 2: System Frequency Monitor Online TSAT is a potential tool to identify abnormally low frequency excursions caused by massive generation drop & high renewable generation penetration (e.g. low RT system inertia) 2 DC Tie RAS events occurred in o Dropped over 2200 and 2500 MW gen, respectively. o Caused the system frequency down to Hz

11 N-2 line outages triggered the RAS fired to trip the units At the 1 st event time, total Wind Generation in XXX BA was close to 0 (luckily). And after a couple of hours the wind went up to 3000 MW. What will happen next time this RAS is fired with high wind penetration Wind in XXX (MW) Event at 6:45 PST TSAT

12 Peak TSAT RAS Models Outline Most RAS models in Peak TSAT were migrated from CAISO-TSAT s Added new ATR model ( RAS) Migrated from WECC Basecase Validated against a recent system event Target to upgrade key RAS upon receiving the new model from TOP Can we validate TSAT RAS model together? Should other RAS shall be included? 12

13 Validating ATR Model ( RAS) in TSAT against PMU on a System Event 13

14 Hurdles to Simulate Transient Cascading in TSAT A system freq. dip event may trigger various cascading generation/load drops TSAT can simulate and predict cascading if (1) protective relays modeled inclusively: 14 o Automatic Under Frequency Load Shedding (UFLS). Per PRC o Generator Frequency and Voltage Protective Relay Settings (PRC-024-2) (2) TSAT software enables cascading analysis

15 A Recent System Event- Cascading Gen Drop Occurred? Multi-500kV lines tripped one after another in 21 seconds Several hydro units tripped at first and lost 1520 MW in total Coal fired power plant tripped and lost 730 MW secondly

16 Use Case 3: Fast Voltage Collapse Study 16 Two scenarios have been defined in TSAT for RT fast voltage collapse study: SDGE Non-Summer IROL SDGE Summer IROL 7 contingencies have been included Induction motor modelled in SDGE area have been mapped and simulated in online TSAT Composite load impact is to be considered

17 Induction Motor Load Modeling Effect In the past two months TSAT online simulation did not capture fast voltage collapse scenarios. Delayed voltage recovery and sparked induction motor current when 50% motor load was applied 17 The testing continues upon summer peak load conditions Composite load effect will be offline studied

18 Next Steps Proof of TSAT model accuracy and solution creditability upon an agreed criteria. We must 18 Improve collaboration with BA/TOP, share and validate TSAT models and solution results Leverage PMU and offline study tools for TSAT results validation Provide actionable information to dispatchers Be specific and accurate Applicable for making a mitigation plan

19 Hongming Zhang