Systems and Methods for Under-Frequency Blackout Protection

• US 20120053744A1
• Filed: 08/01/2011
• Published: 03/01/2012
• Est. Priority Date: 08/24/2010
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Manson, Scott M.
• Granted Patent: US 9,008,850 B2
• Time in Patent Office: Days
• US Class Current: 700/293
• CPC Class Codes: H02H 3/46 responsive to frequency deviations
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00004 characterised by the power network being locally controlled
• CPC Class Codes: H02J 13/00017 using optical fiber
• CPC Class Codes: H02J 2310/12 The local stationary network supplying a household or a building
• CPC Class Codes: H02J 3/14 by switching loads on to, or off from, network, e.g. progressively balanced loading
• CPC Class Codes: Y02B 70/3225 Demand response systems, e.g. load shedding, peak shaving
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y02P 80/14 District level solutions, i.e. local energy networks
• CPC Class Codes: Y04S 10/18 using switches, relays or circuit breakers, e.g. intelligent electronic devices [IED]
• CPC Class Codes: Y04S 20/222 Demand response systems, e.g. load shedding, peak shaving

Abstract

A system for managing an electric power delivery system is disclosed that includes a set of remote intelligent electronic devices (IEDs) and a central IED. The remote IEDs may be configured to obtain information related to operating frequencies and power consumption levels loads included in the electric power delivery system. The central IED may communicate with the remote IEDs to determine which loads are associated with a sub-grid of the electric power delivery system and whether to disconnected certain loads. Based on this determination, the central IED may direct the remote IEDs to disconnect loads from the electric power delivery system.

Claims

1. A system for managing an electric power delivery system comprising:

a plurality of intelligent electronic devices (IEDs), each IED of the plurality of IEDs being communicatively coupled with a load, wherein each IED of the plurality of IEDs is configured to obtain system information related to an operating frequency of a load and power consumption of a load, and wherein each IED of the plurality of IEDs is configured to selectively disconnect a load from the electric power delivery system; and

a central IED communicatively coupled with the plurality of IEDs, the central IED being configured to receive the system information from the plurality of IEDs and, based on the system information, determine which loads are associated with a sub-grid of the electric power delivery system and whether to disconnect one or more loads associated with the sub-grid from the electric power delivery system.

2. The system of claim 1, wherein the system information comprises an indication that an operating frequency of a load has reached a predetermined under-frequency level.

3. The system of claim 1, wherein the central IED is configured to determine which loads are associated with a sub-grid of the electric power delivery system based on the decay rate of operating frequencies of the plurality of loads included in the system information.

4. The system of claim 1, wherein the central IED is configured to determine which loads are associated with a sub-grid of the electric power delivery system based on the decay times of operating frequencies of the plurality of loads included in the system information.

5. The system of claim 1, wherein the central IED is configured to determine whether to disconnect the one or more loads associated with the sub-grid based on priority information associated with the loads associated with the sub-grid.

6. The system of claim 1, wherein the system information comprises synchronized phasor information.

7. The system of claim 1, wherein the system information comprises information related to the current drawn by the loads.

8. The system of claim 1, wherein the system information comprises information related to the voltage required by the loads.

9. The system of claim 1, wherein the system further comprises a time reference generator configured to provide a common time reference signal to the plurality of IEDs and the central IED for coordinating operations of the plurality of IEDs and the central IED.

10. The system of claim 1, wherein the central IED is further configured to generate a signal provided to the IEDs associated with the one or more loads associated with the sub-grid directing the IEDs to disconnect the one or more loads associated with the sub-grid from the electric power delivery system using a breaker communicatively coupled to the IEDs when it is determined that the one or more loads should be disconnected from the electric power delivery system.

11. A method for managing and electric power delivery system using a central intelligent electronic device (IED) comprising:

receiving, at the central IED from a plurality of IEDs, each IED of the plurality of IEDs being communicatively coupled with a load, system information related to the operating frequencies of the loads and the power consumption of the loads;

determining, by the central IED, which loads are associated with a sub-grid of the electric power delivery system based on the system information; and

determining, by the central IED, whether to disconnect one or more loads associated with the sub-grid from the electric power delivery system.

12. The method of claim 11, wherein the system information comprises an indication that an operating frequency of a load has reached a predetermined under-frequency level.

13. The method of claim 11, wherein determining which loads are associated with a sub-grid of the electric power delivery system is based on the decay rate of operating frequencies of the plurality of loads included in the system information.

14. The method of claim 11, wherein determining which loads are associated with a sub-grid of the electric power delivery system is based on the decay times of operating frequencies of the plurality of loads included in the system information.

15. The method of claim 11, wherein determining whether to disconnect one or more loads associated with the sub-grid from the electric power delivery system is based on priority information associated with the loads associated with the sub-grid.

16. The method of claim 11, wherein the system information comprises synchronized phasor information.

17. The method of claim 11, wherein the system information comprises information related to the current drawn by the loads.

18. The method of claim 11, wherein the system information comprises information related to the voltage required by the loads.

19. The method of claim 11, wherein the method further comprises:

sending, by the central IED, a signal to the IEDs associated with the one or more loads to disconnect the one or more loads from the electric power delivery system using a breaker communicatively coupled with the IEDs associated with the one or more loads based on the outcome of the determining whether to disconnect one or more loads step.

20. An intelligent electronic device (IED) associated with an electric power delivery system, the IED comprising:

an interface configured to receive system information from a plurality of remote IEDs, the system information relating to the operating frequencies and power consumptions of loads associated with the plurality of remote IEDs;

a processor communicatively coupled to the interface;

a computer-readable storage medium communicatively coupled to the processor, the computer-readable storage medium storing instructions that when executed by the processor cause the processor to determine, based on the system information, which loads are associated with a sub-grid of the electric power delivery system and whether to disconnect one or more loads associated with the sub-grid from the electric power delivery system.

21. The IED of claim 20, wherein the system information comprises an indication that an operating frequency of a load has reached a predetermined under-frequency level.

22. The IED of claim 20, wherein the computer-readable storage medium further stores instructions that when executed by the processor cause the processor to determine which loads are associated with a sub-grid of the electric power delivery system based on the decay rate of operating frequencies of the loads included in the system information.

23. The IED of claim 20, wherein the computer-readable storage medium further stores instructions that when executed by the processor cause the processor to determine which loads are associated with a sub-grid of the electric power delivery system based on the decay times of operating frequencies of loads included in the system information.

24. The IED of claim 20, wherein the computer-readable storage medium further stores instructions that when executed by the processor cause the processor to determine whether to disconnect one or more loads associated with the sub-grid from the electric power delivery system is based on priority information associated with the loads associated with the sub-grid.

25. The IED of claim 20, wherein the system information comprises synchronized phasor information.

26. The IED of claim 20, wherein the system information comprises information related to the current drawn by a load.

27. The IED of claim 20, wherein the system information comprises information related to the voltage required by a load.

28. The IED of claim 20, wherein the computer-readable storage medium further stores instructions that when executed by the processor cause the processor to send a signal to the IEDs associated with the one or more loads associated with the sub-grid directing the IEDs to disconnect the one or more loads associated with the sub-grid from the electric power delivery system using a breaker communicatively coupled to the IEDs when it is determined that the one or more loads should be disconnected from the electric power delivery system.