Application and Implementation of State Estimator at Idaho Power Company

1. Application and Implementation of State Estimator at Idaho Power Company S. Kincic and M. Papic

2. Outline • Background • Overview of IPCO and its EMS System • IPC Experience with State Estimator • Modeling Issues • SE in Planning • Conclusions

3. 1. Background • The EMS project has been initialized by Grid Operations and Planning following the recommendations of the US/Canada outage task force on the August 2003 blackout. • The Project addresses the NERC and WECC requirements for EMS functionality identified from the August 14th Blackout as well as improved coordination with additional Off-Line Planning Functions.

4. Background NE Blackout TF Recommendations • Recommendation 22 – Evaluate and adopt better real-time tools for operators and reliability coordinators • Recommendation 24 - Improve quality of system modeling data and data exchange practices • NERC should work with the regional reliability councils to establish regional power system models that enable the sharing of consistent and validated data among entities in the region. Power flow and transient stability simulations should be periodically benchmarked with actual system events to validate model data.

5. 1. Background • Installation and complete modeling of the new EMS has been completed entirely by IPCO EMS team • Project completed in two phases: • Phase I: Implementation of SE and advanced applications (May 2005) • Phase II: Cutover to the new SCADA (May 2007) • SE tuning has been accomplished throughout 2007

6. 2. System Overview Company: Covers 24.000 sq. miles Peak 3300MW Net importer of energy 17 plants Shared ownership of three coal fire plants 4,600 miles of transmission lines 18,000 miles of distribution lines

8. 2. IPC System Model • Planning Model (bus-branch representation) • EMS/Dispatching Model (node-breaker representation) • Models Accuracy and Validation • Inter-Utility Data Exchange • The system representation at any given time includes the static data (network topology) and the system conditions (loads, interchanges, flows) • Wide System Model (WSM)

9. EMS System: Configuration: • Windows Based • One pair of servers for SCADA and Generation Application • One pair of servers for SE and Advanced Application • One pair of servers for ICCP data • One server for DTS • Two modeling Servers

10. EMS System:IPC Data Exchange: IPC PNSC PAC BPA SPPC EHVDP CMRC NWE RDRC PGE PG&E

11. 3. State Estimator • Operates on PNSC model (North West WECC) • Model Includes: • 8000 buses (1400 measured) • 5000 lines • 4000 substations • Receives about 15000 analogs and statuses

12. 3. State Estimator • SE runs every 300 sec. • RTNET includes SE and RTCA • STNET includes PWRFLOW and CA • After every State Estimate , the base case is monitored for violations • Real Time CA runs every 300 sec. • Base Case used for STNET (outage schedule)

13. 4. Modeling Issues • Planning model is used as a source of line and • transformers parameters-occasionally • conversion of p.u. in percentage omitted; • SE uses breaker oriented model-terminals of every • device are attached to two or three nodes. • Assignment of device to incorrect node – topology • error; • Series capacitors composed of modules that can be • Inserted and bypassed separately (often non-seen on company one line). If represented as a single device-Significant power flow error;

14. 4. Modeling Issues • Breaker oriented model-over 30.000 breakers. Status of breakers required or topology error if breaker is in wrong position. Maintenance is required; • Field changes have to be modeled-difficulty in obtaining new data; • Mapping of the measurements into the model if the name change-composite key broken

15. 305A 306A to MPSN METERING MW, MVAR ZBR 302Z 303D M Tie Line to JBRIG REACTOR L342 Capacitors 305 A 306 A to MPSN METERING MW, MVAR M ZBR 302 Z 303 D Tie Line to JBRIG REACTOR L342 Capacitors • Bus configurations • need attention; SCADA model NETWORK model

16. Wrong direction of • measurements; breaker 100 MW 100 MW 56 57 100 MW transformer 100 MW 100 MW LV HV

17. Operating Area (time dependent schedule) BaseN + fractionN Base1 + fraction1 Base2 + fraction2 LoadN Load1 Load2 • Load model; Load model-time dependant schedule for operating area; Individual loads follow the same pattern; No load diversity;

18. Spring Operating Area Winter (time dependent schedule) Commercial Summer schedule Industrial Irrigation schedule schedule West Residential schedule East North South North East Load Load Load Load Load Load Load Load Load Load Load Load Load Detailed load model

19. 5. Application of SE in Planning

20. Translation of dispatching (breaker to breaker) model into the planning model

21. 6. Conclusion • Vendors provide operational structure • Utilities have to address modeling issues • The flow of measurement data among • utilities has to be established • Idaho Power Company has successfully • accomplished these tasks

22. What Next? • Continue working and improving IPCO model. • Developing a process of updating IPCO model with external transmission facilities. • Participating in the development of the WSM • Further Validating of SE, STNET and CA results • Implementing of Metrics for SE Evaluation (*) • Integrating of PMU data into IPCO SE. • Start using POM to evaluate critical contingencies and develop a mitigation plan when the contingency occurs. (*)