Power apparatus and method of location of a fault in a power apparatus on the basis of attenuation coefficients of electromagnetic coefficients of fault generated electromagnetic waves

• US 5,256,976 A
• Filed: 03/01/1991
• Issued: 10/26/1993
• Est. Priority Date: 03/09/1990
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Tagawa, Yoshinori, Utsumi, Tomoaki, Ishikawa, Toshio, Endo, Fumihiro, Yamagiwa, Tokio, Iwaasa, Shuzo
• Primary Examiner(s): Strecker, Gerard R.
• Assistant Examiner(s): DO, DIEP N
• Application Number:
  US07/663,440
• Time in Patent Office: 970 Days
• Field of Search: 324/500, 324/520, 324/522, 324/529, 324/535, 324/536, 324/543, 324/544, 324/551, 324/555, 324/557, 174/11 R, 364/482, 364/483, 364/492
• US Class Current: 324/522
• CPC Class Codes: G01R 31/1254 of gas-insulated power appliances or vacuum gaps testing switches G01R31/327; detecting electrical or mechanical defects in encased switchgear H02B13/065

Abstract

A power apparatus has a network formed by a plurality of interconnected components being, e.g., one or more high voltage conductors in a casing of a metal filled with an insulating gas. Detectors are provided which detect electromagnetic waves, which are generated if there is a fault. The electromagnetic waves are analyzed to detect the location of the fault. The analysis may make use of attenuation coefficients corresponding to each component of the network to extrapolate between detectors on either side of the fault and/or to compare with predetermined wave strengths. A map of the network may be stored in a suitable memory to assist in the calculation of the fault location, and the memory may also store the attenuation coefficients themselves. The location of the fault may then be displayed by a suitable display, to give the time variation of the fault.

Claims

1. A power apparatus comprising:

a plurality of high voltage conductors supported by insulating supporting members within metal containers;

a plurality of spaced apart detectors disposed in the metal containers, each of said detectors being arranged to detect electromagnetic waves generated by a fault of electric insulation belonging to at least one of said high voltage conductors between any pair of said detectors, and to generate corresponding outputs; and

analyzing means for analyzing the location of said fault on the basis of attenuation coefficients of the electromagnetic coefficients of the electromagnetic waves propagated between said any pair of said detectors and said outputs of said detectors.

2. An apparatus according to claim 1, wherein said analysing means further includes means for storing attenuation coefficients of each of said identifiable components.

3. An apparatus according to claim 1, wherein said analysing means further includes means for storing a map corresponding to said identifiable components of said network.

4. An apparatus according to claim 1 wherein said analysis means further includes means for displaying the location of said fault in terms of the time variation thereof.

5. An apparatus according to claim 1, wherein said analysing means includes means for storing a plurality of predetermined electromagnetic wave strengths between each of said detectors, and means for comparing the strength of the electromagnetic waves detected by said detectors with a corresponding one of said predetermined electromagnetic wave strengths, so as to detect any difference between the strength of each electromagnetic wave detected and the corresponding one of said predetermined electromagnetic wave strengths for any pair of said detectors.

6. An apparatus according to claim 1, wherein said network comprises a hollow casing supporting a high voltage conductor, and said components are components of said casing.

7. An apparatus according to claim 6, wherein said casing contains an insulating gas.

8. An apparatus according to claim 6, wherein said components include one or more of :

linear parts of said casing, insulation spacers, T-junctions, disconnecting switches and circuit breakers.

9. An apparatus according to claim 1, wherein said means for determining the location of said fault is arranged to calculate propagation curves of said electromagnetic waves for each of said any pair of said detectors on the basis of said attenuation coefficients, and is arranged to calculate the intersection point of propagation curves, thereby to determine the location of said fault.

10. An apparatus according to claim 1, further including an alarm for indicating the detection of said fault.

28. A method according to claim 2, wherein said predetermined attenuation coefficients include attenuation coefficients for the insulating supporting members and attenuation coefficients for said metal containers.

11. A power apparatus comprising:

a plurality of high voltage conductors supported by insulating support members within metal containers;

a plurality of spaced apart detectors disposed in the metal containers, each of said detectors being arranged to detect electromagnetic waves generated by a fault of electric insulating belonging to at least one of said high voltage conductors between any pair of said detectors, and to generate corresponding outputs; and

analyzing means for storing attenuation coefficients of the electromagnetic coefficients of the electromagnetic waves propagated between said any pair of said detectors, and determining the location of said fault on the basis of said attenuation coefficients and said outputs of said detectors.

12. An apparatus according to claim 11, wherein said network comprises a hollow casing supporting a high voltage conductor, and said components are components of said casing.

13. A power apparatus comprising:

a plurality of high voltage conductors supported by insulating supporting members within metal containers;

a plurality of spaced apart detectors disposed in the metal containers, each of said detectors being arranged to detect electromagnetic waves at least at two detection sites generated by a fault of electric insulation belonging to at least one of said high voltage conductors between any pair of said detectors, and to generate corresponding outputs; and

analyzing means for storing a map corresponding to attenuation coefficients of the electromagnetic waves propagated between said detection sites, and determining said fault position on the basis of said attenuation coefficients and said signals.

14. An apparatus according to claim 13, wherein said network comprises a hollow casing supporting a high voltage conductor, and said components are components of said casing.

15. A power apparatus comprising:

a plurality of high voltage conductors supported by insulating supporting members within metal containers;

a plurality of spaced apart detectors disposed in the metal containers, each of said detectors being arranged to detect electromagnetic waves generated by a fault of electric insulating belonging to at least one of said high voltage conductors between any pair of said detectors, and to generate corresponding outputs; and

analyzing means for analyzing the location of said fault on the basis of attenuation coefficients of the electromagnetic coefficients of the electromagnetic waves propagated between said any pair of said detectors and said outputs of said detectors, and for displaying the location of said fault in terms of the time variation thereof.

16. An apparatus according to claim 15, wherein said network comprises a hollow casing supporting a high voltage conductor, and said components are components of said casing.

17. A power apparatus comprising:

a plurality of high voltage conductors supported by insulating supporting members within metal containers;

a plurality of spaced apart detectors disposed in the metal containers, each of said detectors being arranged to detect electromagnetic waves generated by a fault of electric insulating belonging to at least one of said high voltage conductors between any pair of said detectors, and to generate corresponding outputs; and

analyzing means for storing a plurality of predetermined electromagnetic wave strengths between each of said detectors, comparing the strength of the electromagnetic waves detected by said detectors with a corresponding one of said predetermined electromagnetic wave strengths, and detecting fault position on the basis of any difference between the strength of each of said predetermined electromagnetic wave strengths and the strength of the electromagnetic waves detected by said any pair of said detectors.

18. An apparatus according to claim 17, wherein said network comprises a hollow casing supporting a high voltage conductor, and said components ar components of said casing.

19. A fault location system for locating a fault position of electric insulation belonging to high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, said system comprising:

a plurality of detectors for detecting electromagnetic waves at least at two detection sites in the metal containers and generating corresponding outputs; and

analysis means for storing a map of said high voltage conductors in said power apparatus, storing attenuation coefficients corresponding to each of said high voltage conductors, and analyzing the fault position on the basis of said outputs, said map and said attenuation coefficients.

20. A fault location system for locating a fault position of electric insulation belonging to high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, said system comprising:

a plurality of detectors for detecting electromagnetic waves at least at two detection sites in the metal containers and generating corresponding outputs; and

analysis means for storing attenuation coefficients corresponding to each of said high voltage conductors, analyzing the fault position on the basis of said outputs and said attenuation coefficients, and displaying the fault position in terms of a time variation thereof.

21. A method of locating a fault position of electric insulating belonging to at least one of high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, the method comprising:

detecting electromagnetic waves at least at two detection sites in the metal containers, said electromagnetic waves being generated by said fault in the metal container;

generating signals corresponding to said detected electromagnetic waves; and

analyzing said fault position on the basis of attenuation coefficients of the electromagnetic waves propagated between said detection sites and said signals.

22. A method according to claim 21 wherein said analysis further includes storing attenuation coefficients.

23. A method according to claim 21, wherein said analysis further includes storing a map corresponding to said high voltage conductors.

24. A method according to claim 21, further including displaying said fault position in terms of the time variation thereof.

25. A method according to claim 21, wherein said analysis further includes calculating a difference between strengths of electromagnetic waves detected at said detection sites, and comparing said difference between the strengths of electromagnetic waves with a propagation amount based on the attenuation coefficient between said detection sites so as to locate the fault position.

26. A method according to claim 21, wherein said analysis further includes calculating propagation curves of said electromagnetic waves between said detection sites on the basis of said attenuation coefficients and calculating an intersection point of said propagation curves, thereby determining the location of said fault.

27. A method according to claim 26, wherein the step of analyzing included determining the fault position on the basis of predetermined attenuation coefficients for individual components of said power apparatus.

29. A method of locating a fault position of electric insulating belonging to at leas tone of high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, the method comprising:

detecting electromagnetic waves at least at two detection sites in the metal containers, said electromagnetic waves being generated by said fault in the metal container;

generating signals corresponding to said detected electromagnetic waves; and

analyzing said signals to locate said fault position, said analysis involving storing attenuation coefficients of the electromagnetic waves propagated between said detection sites, and determining said fault position on the basis of said attenuation coefficients and said signals.

30. A method of locating a fault position of electric insulating belonging to at least one of high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, the method comprising:

detecting electromagnetic waves at least at two detection sites in the metal containers, said electromagnetic waves being generated by said fault in the metal containers;

generating signals corresponding to said detected electromagnetic waves; and

analyzing said signals to locate said fault position, said analysis involving storing a map corresponding to attenuation coefficients of the electromagnetic waves for predetermined components of said power apparatus located between said detection sites and determining said fault position on the basis of said attenuation coefficients and said signals.

31. A method of locating a fault position of electric insulation belonging to at least one of high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, the method comprising:

detecting electromagnetic waves at least at two detection sites in the metal containers, said electromagnetic waves being generated by said fault in the metal container;

generating signals corresponding to said detected electromagnetic waves; and

analyzing said signals to locate said fault position, said analysis involving displaying the location of said fault position in terms of time variations of the electromagnetic waves propagated between said detection sites.

32. A method of locating a fault position of electric insulation belonging to at least one of high voltage conductors supported by insulating supporting members within metal containers in a power apparatus, the method comprising:

detecting electromagnetic waves at least at two detection sites in the metal containers, said electromagnetic waves being generated by said fault in the metal containers;

generating signal corresponding to said detected electromagnetic waves; and

analyzing said signals to locate said fault position, said analysis involving calculating propagation curves of said electromagnetic waves propagated between said detection sites on the basis of attenuation coefficients of the electromagnetic waves propagated between said detection sites and said signals, and calculating an intersection point of said propagation curves, thereby determining the location of said fault position.