Correlation between discharge magnitude distribution and discharge luminescence distribution due to electrical treeing

An investigation was conducted to diagnose deteriorating insulation in order to predict the breakdown of electrical equipment due to the deterioration. An internal-discharge-pulse-measurement system which could analyze the discharge magnitude according to the phase area of the applied AC 50-Hz voltage was used to diagnose the degree of deterioration. The process was analyzed from the occurrence of the discharge to the development of treeing in an artificial void. The discharge luminescence could be observed in detail using digital image processing. Before the initiation of the tree, a swarming pulsed microdischarge occurred. The discharge luminescence was almost constant. After the initiation of the tree, the discharge magnitude and the number of discharge current pulses rapidly increased on the discharge magnitude distribution.<
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