Power Research Institute, Central Water and Power Commission (Power Wing), Bangalore.
In this paper, the studies of Discharge Patterns originating from discharges in artificially created cavities of various dimensions and at various locations in polythene dielectric are reported. On the basis of experimental work at Discharge Detection Laboratory in Power Research Institute, Bangalore, it is concluded that discharge inception voltage is independent of void diameter. For voids of increasing depths, the discharge inception voltage decreases and discharge magnitudes tend to increase. The position of void inside the dielectric has little effect on the discharge inception voltage but approximate location is possible by merely looking at the discharge pattern. The recurrence frequency and magnitude of discharges increases with increase of test voltage beyond the inception value, thus suggesting increasing deterioration of the dielectric. For a satisfactory performance of an electrical equipment during its service, occurrence of discharges must be controlled.
