Insulated device diagnosing system for diagnosing device based upon partial discharge signal data analyzed by frequency

• US 5,982,181 A
• Filed: 12/08/1997
• Issued: 11/09/1999
• Est. Priority Date: 12/09/1996
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Rokunohe, Toshiaki, Endo, Fumihiro, Yamagiwa, Tokio, Shinohara, Ryouichi
• Primary Examiner(s): Do, Diep N.
• Application Number:
  US08/986,618
• Time in Patent Office: 701 Days
• Field of Search: 324/520, 324/522, 324/536, 324/541, 324/544, 324/545, 324/546, 324/547, 324/551, 702/58, 702/59, 702/65, 702/182, 702/183, 702/184, 702/185, 340/646, 340/647, 340/648
• US Class Current: 324/551
• 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
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

An insulated device diagnosing system is capable of judging the deterioration, lifetime, and defects of a device. The intensity at each voltage phase angle is measured at a plurality of specific frequencies, taking high voltage phase angles as the abscissas. The deterioration, lifetime, and the kind and extent of abnormality of the device are judged from the pattern and intensity of the spectral distribution, which is obtained by peak-holding the measured intensity for a defined time period. According to the present invention, partial discharge can be measured highly sensitively and precisely to diagnose the deterioration, lifetime and the extent of defect of the device. As a result, the insulation reliability of the device can be improved, and the part of the device that should be repaired/replaced can be grasped before disassembly of the device, thereby cutting the maintenance cost.

Claims

1. An insulated device diagnosing system comprising:

an antenna provided in an insulated device;

a pattern generator for receiving a partial discharge signal from said antenna, said partial discharge signal resulting from electromagnetic wave energy of a partial discharge received by said antenna, and preparing detection data from the partial discharge signal such that periodic elements are given to a plurality of specific frequencies of the partial discharge signal;

a neuro computer or a finger printing method operation unit for processing the detection data prepared by said pattern generator; and

a judgment unit for diagnosing an extent of abnormality, a deterioration, or lifetime of said insulated device from the operation result of said neuro computer or finger printing method operation unit.

2. An insulated device diagnosing system according to claim 1, wherein a distribution of frequency components of the detection signal is also measured for specifying the specific frequencies to be detected.

3. An insulated device diagnosing system according to claim 2, wherein said insulated device is a gas insulated breaker, wherein said partial discharge signals coming from a plurality of antennas provided at different positions in said gas insulated device are measured synchronously, and wherein the partial discharge is located from the spectral patterns or intensity ratios of said detection data between the same frequencies.

4. An insulated device diagnosing system according to claim 1, wherein said insulated device is a gas insulated breaker, wherein said partial discharge signals coming from a plurality of antennas provided at different positions in said gas insulated device are measured synchronously, and wherein the partial discharge is located from the spectral patterns or intensity ratios of said detection data between the same frequencies.

5. A partial discharge detecting method comprising the steps of:

inputting a partial discharge signal of an insulated device from an input terminal, the partial discharge signal resulting from electromagnetic wave energy of a partial discharge;

preparing detection data from the partial discharge signal which are given periodic elements at a plurality of specific frequencies of the partial discharge signal; and

diagnosing an extent of abnormality, deterioration, or lifetime of the insulated device from a pattern or intensity of the prepared detection data.

6. A partial discharge detecting method according to claim 5, wherein the extent of abnormality, the deterioration, or the lifetime of the insulated device is diagnosed by processing said detection data by a neuro computer method or by a finger printing method.

7. A partial discharge detecting method comprising the steps of:

inputting a partial discharge signal of an insulated device from an input terminal, the partial discharge signal resulting from electromagnetic wave energy of a partial discharge;

determining the intensity in which said partial discharge signal is expanded for each frequency by an FFT or a spectral analyzer to select a plurality of specific frequencies from frequencies having high intensities, detecting the intensity of each frequency of said partial discharge signal to select a plurality of specific frequencies, of which the intensities exceed a predetermined value, or selecting the frequency having the highest intensity from the specific frequencies;

preparing detection data from the partial discharge signal which are given periodic elements at a specific frequency selected of the partial discharge signal; and

processing at least one of said detection data or displaying at least one of the detection data on a screen to detect partial discharge.

8. A partial discharge detecting method according to claim 7, wherein an extent or kind of abnormality, deterioration, or lifetime of the insulated device is diagnosed by processing said detection data by a neuro computer method or by a finger printing method.

9. A partial discharge detecting method comprising the steps of:

inputting a partial discharge signal from an input terminal, the partial discharge signal resulting from electromagnetic wave energy of a partial discharge;

preparing detection data from the partial discharge signal such that a plurality of specific frequencies of the partial discharge signal are given periodic elements;

preparing sampling data by differentiating either averaged data averaged from detection data of different frequencies or known data from the individual detection data, or by differentiating the intensities of the detection data detected by antennas provided in different positions of the insulated device, between identical frequencies; and

diagnosing an extent of abnormality, deterioration, or lifetime of the insulated device from the pattern or the intensities of the prepared sampling data.

10. A partial discharge detecting method comprising the steps of:

preparing detection data given periodic elements from one of a plurality of specific frequencies of a partial discharge signal, the partial discharge signal resulting from electromagnetic wave energy of a partial discharge; and

processing said detection data or displaying the detection data on a screen to detect a partial discharge.