Systems and methods for blackout protection

• US 8,965,592 B2
• Filed: 08/16/2012
• Issued: 02/24/2015
• 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.
• Primary Examiner(s): Dunn, Darrin
• Application Number:
  US13/587,068
• Publication Number:
  US 20130018521A1
• Time in Patent Office: 922 Days
• Field of Search: 700/21, 700/79, 700/177, 700/286, 700/292, 700/295, 713/300, 713/340
• US Class Current: 700/292
• CPC Class Codes: H02H 3/033 with several disconnections in a preferential order, e.g. following priority of the users, load repartitionH02H3/06 takes precedence
• CPC Class Codes: H02H 3/46 responsive to frequency deviations
• CPC Class Codes: H02J 13/00017 using optical fiber
• CPC Class Codes: H02J 13/0004 involved in a protection system
• CPC Class Codes: H02J 2310/60 Limiting power consumption in the network or in one section of the network, e.g. load shedding or peak shaving
• 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: 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 rotor angles, operating frequencies, rate of change of frequency, rotating inertia, and power consumption levels of loads and generators included in the electric power delivery system. The central IED may communicate with the remote IEDs to determine which loads and generators are associated with a sub-grid of the electric power delivery system and whether to disconnected certain loads or generators. Based on this determination, the central IED may direct the remote IEDs to disconnect loads or generators from the electric power delivery system, or to rapidly increase or decrease generator output as appropriate.

Claims

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

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

a second plurality of IEDs, each IED of the second plurality of IEDs being communicatively coupled with a corresponding generator, wherein each IED of the second plurality of IEDs is configured to obtain generator information from the corresponding generator, and wherein each IED of the second plurality of IEDs is configured to selectively modify load or generation on the electric power delivery system; and

a central IED communicatively coupled with the first and second plurality of IEDs, the central IED being configured to;

receive the load and generator information;

obtain operating frequencies of the loads and calculate decay rates of the operating frequencies;

when an operating frequency of a load has reached a predetermined under- frequency level, determine which loads are associated with a same sub-grid, wherein loads with similar decay rates are determined to be associated with the same sub-grid;

based on the load and generator information, determine an amount of generation or load to be modified; and

,

signal appropriate IEDs of the first and second plurality of IEDs to modify associated generation or load;

wherein the load information comprises information relating to a rotating inertia of the one or more loads and the generator information comprises rotating inertia of the one or more generators;

wherein the decay rates comprise times at which operating frequencies reach a predetermined under-frequency level.

2. The system of claim 1, wherein the second plurality of IEDs is configured to selectively disconnect the corresponding generator from the electric power delivery system.

3. The system of claim 1, wherein the second plurality of IEDs is configured to selectively run-back the corresponding generator.

4. The system of claim 1, wherein the second plurality of IEDs is configured to selectively run-up the corresponding generator.

5. The system of claim 1, wherein the load information further comprises one or more selected from the group consisting of:

rotor angle;

operating frequency;

rate of change of operating frequency; and

power consumption.

6. The system of claim 1, wherein the generator information further comprises one or more selected from the group consisting of:

rotor angle;

operating frequency;

rate of change of operating frequency; and

power consumption.

7. The system of claim 1, wherein the central IED is further configured to determine a system rotating inertia based on the received load and generator information.

8. The system of claim 7, wherein the central IED is further configured to determine an operating frequency based on the load and generator information.

9. The system of claim 8, wherein the central IED is further configured to determine an amount of additional power contribution required from the generators based on a comparison between the operating frequency and one or more predetermined thresholds and to signal appropriate IEDs of the first and second plurality of IEDs to shed an appropriate amount of load based thereon.

10. The system of claim 8, where the central IED is further configured to determine an amount of power reduction from the generators based on a comparison between the operating frequency and one or more predetermined thresholds and to signal appropriate IEDs of the first and second plurality of IEDs to shed an appropriate amount of generation based thereon.

11. The system of claim 1, wherein the load and generator information comprise synchronized phasor information.

12. The system of claim 1, wherein the load and generator information comprise binary information.

13. The system of claim 1, wherein the central IED is further configured to receive load composition information from the first plurality of IEDs and to determine an appropriate amount of load to shed based thereon.

14. The system of claim 1, wherein the central IED detects island formation by time-correlation of the received load and generation information.

15. The system of claim 1, wherein the central IED comprises a first central IED, the system further comprising a second central IED, the first and second central IEDs being associated with different interconnected grids, and the first and second central IEDs configured to share load information.

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

receiving, at the central IED from a first plurality of IEDs, each of the first plurality of IEDs being communicatively coupled with a load, load information comprising rotating inertia information of a plurality of loads;

obtaining operating frequencies of the loads and, based on the operating frequencies, calculate decay rates of the operating frequencies;

when an operating frequency of a load has reached a predetermined under-frequency level, determining which loads are associated with a same sub-grid, where loads with similar decay rates are determined to be associated with the same sub-grid;

receiving, at the central IED from a second plurality of IEDs, each of the second plurality of IEDs being communicatively coupled with a respective generator, generator information comprising rotating inertia information of the generators;

determining, by the central IED, an amount of generation or load to modify based on the load and generator information; and

signaling, by the central IED, appropriate IEDs of the first and second plurality of IEDs to modify associated generation or load based on the determined amount of generation or load to modify;

wherein the decay rates comprise times at which operating frequencies reach a predetermined under-frequency level.

17. The method of claim 16, wherein the amount of generation or load to modify comprises an amount of generation to shed, and the signaling comprises signaling appropriate IEDs to shed associated generation based on the determined amount of generation to shed.

18. The method of claim 16, wherein the amount of generation or load to modify comprises an amount of generation to run-back, and the signaling comprises signaling appropriate IEDs to run-back associated generation based on the determined amount of generation to run-back.

19. The method of claim 16, wherein the amount of generation or load to modify comprises an amount of generation to run-up, and the signaling comprises signaling appropriate IEDs to run-up associated generation based on the determined amount of generation to run-up.

20. The method of claim 16, wherein the load information further comprises one or more selected from the group consisting of:

rotor angle;

operating frequency;

rate of change of operating frequency; and

power consumption.

21. The method of claim 16, wherein the generator information further comprises one or more selected from the group consisting of:

rotor angle;

operating frequency;

rate of change of operating frequency; and

power consumption.

22. The method of claim 16, wherein the method further comprises:

determining, by the central IED, a system rotating inertia based on the received load and generator information.

23. The method of claim 22, wherein the method further comprises:

determining, by the central IED, an operating frequency based on the received load and generator information.

24. The method of claim 23, wherein the method further comprises:

determining, by the central IED, an amount of additional power contribution required from the generators based on a comparison between the operating frequency and one or more predetermined thresholds; and

signaling, by the central IED, to appropriate IEDs of the first and second plurality of IEDs to shed an appropriate amount of load based thereon.

25. The method of claim 23, wherein the method further comprises:

determining, by the central IED, an amount of power reduction from the generators based on a comparison between the operating frequency and one or more predetermined thresholds; and

signaling, by the central IED, to signal appropriate IEDs of the first and second plurality of IEDs to shed an appropriate amount of generation based thereon.

26. The method of claim 16, wherein the load and generator information comprise synchronized phasor information.

27. The method of claim 16, wherein the load and generator information comprise binary information.

28. The method of claim 16, wherein the method further comprises:

receiving, by the central IED from the first plurality of IEDs, load composition information; and

determining, by the central IED, an appropriate amount of load to shed based on the load composition information.

29. The method of claim 16, further comprising detecting island formation by time-correlation of the received load and generation information.

30. The method of claim 16, wherein the central IED comprises a first central IED, the method further comprising:

first central IED sharing load information with a second central IED, the first and second central IEDs being associated with different interconnected grids.

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

an interface configured to receive;

load information from a first plurality of IEDs, each of the first plurality of IEDs being communicatively coupled with a load and configured to selectively disconnect a load from the electric power delivery system, the load information comprising rotating inertia information of a plurality of loads and operating frequencies of the plurality of loads, and

generator information from a second plurality of IEDs, each of the second plurality of IEDs being communicatively coupled with a respective generator and configured to selectively disconnect the respective generator from the electric power delivery system, the generator information comprising rotating inertia information of the respective generators;

a processor communicatively coupled to the interface; and

a non-transitory 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;

based on the operating frequencies of the loads, calculate decay rates of the operating frequencies;

when an operating frequency of a load has reached a predetermined under-frequency level, determine which loads are associated with a same sub-grid, where loads with similar decay rates are determined to be associated with the same sub-grid;

determine an amount of generation to shed, run-back, or run-up, or load to be shed based on the load and generator information and to signal appropriate IEDs of the first and second plurality of IEDs to shed, run-back, or run-up associated generation or shed associated load based on the determined amount of generation to be shed, run-back, or run-up, or load to be shed;

wherein the decay rates comprise times at which operating frequencies reach a predetermined under-frequency level.

32. The IED of claim 31, wherein the interface is further configured to share load information from the first plurality of IEDs and generator information from the second plurality of IEDs with a central IED associated, where the IED and the central IED are associated with different interconnected grids.