Coordinated high-impedance fault detection systems and methods

Patent metadata

Field	Value
Publication number	US-9160158-B2
Application number	US-201314052449-A
Country	US
Kind code	B2
Filing date	Oct 11, 2013
Priority date	Oct 12, 2012
Publication date	Oct 13, 2015
Grant date	Oct 13, 2015

Abstract

Systems and methods are presented for detecting high-impedance faults (HIFs) in an electric power delivery system using a plurality of coordinated high-impedance fault detection systems. In certain embodiments, a method for HIFs may include receiving first and second current representations associated with first and second locations of the electric power delivery system respectively. Based on at least one of the first and second current representations, the occurrence of an HIF may be determined. A relative location of the HIF may be determined based on a relative amount of interharmonic content associated with an HIF included in the first and second current representations, and a protective action may be taken based on the determined relative location.

First claim

What is claimed is:

1. A method for detecting high-impedance faults in an electric power delivery system comprising:
receiving a first current representation associated with a first location of the electric power delivery system;
receiving a second current representation associated with a second location of the electric power delivery system;
determining, based on at least one of the first and second current representations, the occurrence of a high-impedance fault on the electric power delivery system;
determining a relative location of the high-impedance fault based, at least in part, on a relative amount of signal content associated with a high-impedance fault included in the first and second current representations;
coordinating a first protective action by one of a first intelligent electronic device (IED) and a second IED based on the determined relative location of the high-impedance fault, and
implementing the first protective action by one of the first IED and the second IED based on the determined relative location.

2. The method of claim 1 , wherein the first current representation comprises a measurement by the first IED and the second current representation comprises a measurement by the second IED.

3. The method of claim 1 , wherein the first protective action comprises issuing a control signal to electrically isolate a portion of the electric power delivery system including the high-impedance fault.

4. The method of claim 1 , further comprising:
determining the relative location of the high-impedance fault comprises determining that the high-impedance fault is located closer to the first location than then second location; and
wherein implementing the first protective action comprises the first IED issuing a control signal to electrically isolate a portion of the electric power delivery system including the high-impedance fault.

5. The method of claim 1 , wherein determining the occurrence of the high-impedance fault comprises determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault.

6. The method of claim 5 , wherein determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault comprises determining that at least one of the first current representation and the second current representation comprises signal content exceeding a detection threshold.

7. The method of claim 5 , wherein determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault further comprises determining that at least one of the first current representation and the second current representation comprises signal content exceeding the detection threshold by a number of times in a particular period.

8. The method of claim 7 , wherein the particular period is based on a relative magnitude of the signal content.

9. The method of claim 5 , wherein determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault comprises adjusting at least one of the first current representation and the second current representation by a reference and determining that the adjusted information comprises signal content exceeding a detection threshold.

10. The method of claim 9 , wherein the reference comprises an average level of signal content associated with normal system noise.

11. The method of claim 10 , wherein the detection threshold is adjusted based on the reference.

12. The method of claim 1 , wherein the method further comprises:
determining, based on at least one of the first and second current representations, that a portion of the electric power delivery system including the high-impedance fault has not been isolated after implementing the first protective action; and
implementing a second protective action to isolate the high-impedance fault.

13. The method of claim 12 , wherein the first protective action comprises issuing a first control instruction to electrically isolate a first portion of the electric power delivery system and the second protective action comprises issuing a second control instruction to electrically isolate a second portion of the electric power delivery system.

14. An intelligent electronic device (IED) associated with an electric power delivery system, the IED comprising:
an interface configured to receive first current representation associated with a first location of the electric power delivery system and second current representation associated with a second location of the electric power delivery system;
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 at least one of the first and second current representations, the occurrence of a high-impedance fault on the electric power delivery system, determine a relative location of the high-impedance fault based, at least in part, on a relative amount of signal content associated with a high-impedance fault included in the first and second current representations, coordinating a first protective action by one of a first intelligent electronic device (IED) and a second IED based on the determined relative location of the high-impedance fault, and implement the first protective action by one of the first IED and the second IED based on the determined relative location.

15. The IED of claim 14 , wherein the first protective action comprises issuing a control signal, via the interface, to electrically isolate a portion of the electric power delivery system including the high-impedance fault.

16. The IED of claim 14 , wherein the first current representation is received from a first IED and the second current representation is received form a second IED and determining the relative location of the high-impedance fault comprises determining that the high-impedance fault is located closer to the first location than then second location and implementing the first protective action comprises instructing the first IED to issue a control signal to trip a breaker to isolate a portion of the electric power delivery system including the high-impedance fault.

17. The IED of claim 14 , wherein determining the occurrence of the high-impedance fault comprises determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault.

18. The IED of claim 17 , wherein determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault comprises determining that at least one of the first current representation and the second current representation comprises signal content exceeding a detection threshold.

19. The IED of claim 18 , wherein determining that at least one of the first current representation and the second current representation comprises signal content associated with a high-impedance fault comprises adjusting at least one of the first current representation and the second current representation by a reference and determining that the adjusted information comprises signal conte

Assignees

• Schweitzer Engineering Lab Inc

Inventors

• Schweitzer Iii Edmund O
• Mynam Mangapathirao Venkata
• Hou Daqing

Classifications

• H02H3/08 Primary

  responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) · CPC title

• H02H7/261

  involving signal transmission between at least two stations (transmission of signals in general H02H1/0061) · CPC title

• H02H3/52 Primary

  responsive to the appearance of harmonics · CPC title