On-line detection of partial discharge in electrical power systems
First Claim
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1. A method of on-line analysis of location of partial discharge events during operation of an a.c. power system in which a.c. power is being applied through a cable to a load, comprising the steps of:
- (a) detecting in the cable high frequency electromagnetic pulses generated by partial discharge events in the power system caused by continuing application of a.c. power to the system, (b) analyzing said pulses detected in said step (a) in the frequency domain to identify a frequency component of greatest magnitude in said pulses and the frequency of said component, (c) analyzing pulses detected in said step (a) in the time domain at the frequency of said component identified in said step (b) to determine a phase relationship between said frequency component and cycles of the a.c. power in the system, (d) identifying location of partial discharge events in the power system as a function of said frequency component identified in said step (b) and said phase relationship determined in said step (c), (e) determining a phase relationship between pulses detected in said step (a) and the a.c. power being applied to said system, and (f) determining a type of fault in said system that causes said partial discharge events as a function of said phase relationship determined in said step (e).
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Abstract
A method and apparatus for on-line detection of partial discharge events in an a.c. power system, in which high frequency electromagnetic pulses generated by partial discharge events are detected and analyzed in the frequency domain and the time domain to determine the type and location of the partial discharge event. The phase relationship between the partial discharge events and the on-line power signal is also examined to help indicate severity of the insulation anomaly giving rise to the partial discharge events.
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5 Claims
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1. A method of on-line analysis of location of partial discharge events during operation of an a.c. power system in which a.c. power is being applied through a cable to a load, comprising the steps of:
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(a) detecting in the cable high frequency electromagnetic pulses generated by partial discharge events in the power system caused by continuing application of a.c. power to the system, (b) analyzing said pulses detected in said step (a) in the frequency domain to identify a frequency component of greatest magnitude in said pulses and the frequency of said component, (c) analyzing pulses detected in said step (a) in the time domain at the frequency of said component identified in said step (b) to determine a phase relationship between said frequency component and cycles of the a.c. power in the system, (d) identifying location of partial discharge events in the power system as a function of said frequency component identified in said step (b) and said phase relationship determined in said step (c), (e) determining a phase relationship between pulses detected in said step (a) and the a.c. power being applied to said system, and (f) determining a type of fault in said system that causes said partial discharge events as a function of said phase relationship determined in said step (e). - View Dependent Claims (2, 3, 4, 5)
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Specification