P ower M onitoring A nd C ontrol S ystem (PMACS)

1. Power Monitoring And Control System (PMACS) NETPUNE Quarterly Meeting April 1st, 2005 University of Washington Chen-Ching Liu Ting Chan Kevin Schneider

2. Presentation Overview • MARS PMACS • Overview of MARS PMACS • Data communications system (DCS) • Energy management system (EMS) software • NEPTUNE PMACS • Overview of NEPTUNE PMACS • Observatory control • Energy management system (EMS) functions

3. Monterey Accelerated Research System (MARS) PMACS

4. MARS PMACS Overview • Information is communicated from a single science node to a single shore station. • PMACS operates at the shore station based on data received from the science node. • PMACS is remotely accessible to authorized users. • PMACS can generate control signals which affect the shore station voltage as well as science node breakers.

5. MARS DCS

6. MARS DCS cont.

7. MARS PMACS Top Level Architecture

8. MARS PMACS Structure

9. MARS State Estimation • Using a limited number of measurements and a weighted least squares (WLS) algorithm the state of the system can be estimated. • Allows for the identification of “bad” data. • Helps reduce the overall measurement error in the system.

10. MARS State Estimation Cont.

11. MARS State Estimation Cont.

12. MARS Fault Location • Primary: Time domain reflectometry (TDR). • Secondary: Ohm’s Law calculation from shore station voltage and current.

13. MARS Fault Location Cont. • The fault location module of PMACS would be used as a supplement of the stand alone Time Domain Reflectometry. • Secondary: Ohm’s Law calculation from shore station voltage and current. • Cable resistance = 1.5 Ω/km • Measurement errors = 0.01% (voltage and current)

14. MARS Hardware and Software

15. Concluding Remarks for MARS PMACS

16. North East Pacific Time-Series Underwater Networked Experiment (NEPTUNE) PMACS

17. NEPTUNE PMACS Overview • Information is communicated from multiple science nodes to two shore stations. • PMACS operates at the shore stations based on data received from the science nodes. • PMACS is remotely accessible to authorized users. • PMACS can generate control signals which affect the shore station voltage as well as science node breakers.

18. NEPTUNE PMACS Architecture

19. Topology Identification • Allows for the possibility of a single back bone breaker being out of position. • Necessary for proper operation of EMS function. • Traditional methods will not work because of the design of NEPTUNE.

20. Topology Identification Cont. Correct Assumed Topology Incorrect Assumed Topology

21. Load Management and Emergency Control • Uses values from science nodes, shore stations, and state estimation to determine if the current system load violates any limits. • Interfaces with Data Management and Archiving System (DMAS) as well as observatory control. • Performs traditional security assessment in a limited manner.

22. Fault Location • Since NEPTUNE is a networked system Ohm’s Law alone is not sufficient to determine the location of a fault. • Zener diodes in the BUs are non linear elements which further complicate the issue.

23. Fault Location Cont. • System Modeling • Since faulted link and network topology are known, build system model including line resistance and voltage drop across Bus. • Shore stations voltages and currents are known • Set up multiple nonlinear equations.

24. Fault Location Cont.

25. Observatory Control • Observatory control operates above PMACS. • Has the final authority of what load can be shed by PMACS and when. • Contains the “user contract” which governs the interaction between PMACS and the end users, i.e. scientist.

26. Power and Communications Interface • Failures in the communications or computer systems can have a significant impact on power system operations. • Analytic evaluations of these interaction need to be performed.

27. Concluding Remarks