Partial discharge monitoring system for transformers
First Claim
1. An apparatus for detecting partial discharge in on-line high voltage electrical equipment containing a dielectric each partial discharge generating a radio frequency pulse or wave and an ultrasonic pulse or wave, the apparatus comprising:
- at least one transducer means for detecting the ultrasonic pulse or wave generated by the occurrence of a partial discharge and subsequently outputting a signal corresponding to this detection;
at least one transducer means for detecting the radio frequency pulse or wave generated by the occurrence of a partial discharge and other radio frequency pulses or waves generated within or external to the equipment and subsequently outputting a signal corresponding to this detection; and
a signal processing and analysing means which receives the signals corresponding to the detection of the radio frequency and ultrasonic pulses or waves and which on receiving a signal corresponding to detection of an ultrasonic pulse or wave is adapted to;
(a) determine within a pre-set time period preceding the instance of time of detection of the ultrasonic pulse or wave the time delay between the instance of detection of all detected radio frequency pulses or waves and the instance of detection of said ultrasonic pulse or wave and generate a spread of time delay values over the pre-set time period;
(b) superimpose the spread of time delay values against other spreads of time delay values of a plurality of other detected ultrasonic pulses or waves; and
(c) analyse the superimposed spreads of time delay values to determine if a proportion of the detected ultrasonic pulses or waves are being detected at one or more particular time delay values after the time of detection of the detected radio frequency pulses or waves.
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Accused Products
Abstract
An apparatus for detecting partial discharge in on-line high voltage electrical equipment containing a dielectric, such as high voltage transformers. The apparatus includes an ultrasonic transducer and an annular capacitive plate for detecting, respectively, the ultrasonic pulse and the radio frequency pulse generated by the occurrence of partial discharge in the equipment. The outputs of the transducers are analyzed by signal processing means to allow determination of occurrences of true partial discharge from the plethora of electrical noise normally present in on-line voltage equipment
71 Citations
28 Claims
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1. An apparatus for detecting partial discharge in on-line high voltage electrical equipment containing a dielectric each partial discharge generating a radio frequency pulse or wave and an ultrasonic pulse or wave, the apparatus comprising:
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at least one transducer means for detecting the ultrasonic pulse or wave generated by the occurrence of a partial discharge and subsequently outputting a signal corresponding to this detection;
at least one transducer means for detecting the radio frequency pulse or wave generated by the occurrence of a partial discharge and other radio frequency pulses or waves generated within or external to the equipment and subsequently outputting a signal corresponding to this detection; and
a signal processing and analysing means which receives the signals corresponding to the detection of the radio frequency and ultrasonic pulses or waves and which on receiving a signal corresponding to detection of an ultrasonic pulse or wave is adapted to;
(a) determine within a pre-set time period preceding the instance of time of detection of the ultrasonic pulse or wave the time delay between the instance of detection of all detected radio frequency pulses or waves and the instance of detection of said ultrasonic pulse or wave and generate a spread of time delay values over the pre-set time period;
(b) superimpose the spread of time delay values against other spreads of time delay values of a plurality of other detected ultrasonic pulses or waves; and
(c) analyse the superimposed spreads of time delay values to determine if a proportion of the detected ultrasonic pulses or waves are being detected at one or more particular time delay values after the time of detection of the detected radio frequency pulses or waves. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A process for detecting partial discharge in on-line electrical equipment containing a dielectric, each partial discharge generating a radio frequency pulse or wave and an ultrasonic pulse or wave, the process comprising the steps:
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(i) detecting radio frequency pulses or waves generated within the equipment;
(ii) detecting ultrasonic pulses or waves generated within the equipment;
(iii) on detection of an ultrasonic pulse or wave, determining within a pre-set time period preceding the instance of time of detection of the ultrasonic pulse or wave, the time delay between the instance of detection of all detected radio frequency pulses or waves and the instance of detection of said ultrasonic pulse or wave and generate a spread of time delay values over the pre-set time period;
(iv) superimposing the spread of time delay values against other spreads of time delay values of a plurality of other detected ultrasonic pulses or waves; and
(v) analysing the superimposed spreads of time delay values to determine if a proportion of the detected ultrasonic pulses or waves are being detected at one or more particular time delay values after the time of detection of the detected radio frequency pulses or waves.
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Specification