Experimental study on the development characteristics of point discharge in GIS

Studying the characteristics of partial discharge development is conducive to make an accurate assessment of the severity of discharges and give a reasonable maintenance strategy for the equipment. Point discharge is a typical failure discharge fault occurred in GIS equipment, the differences of the characteristics of the PRPD patterns produced by UHF partial discharge enveloped signals in different development stage is studied and the variation with the test time of the average amplitude and number of discharges in each sampling period, the max discharge amplitude ratio and discharge frequency ratio of positive and negative half-cycle is discussed in this paper. It provides a basis for assess the severity of partial discharge. The results show that, with the extension of the test time, the average amplitude and number of discharges increase first, and then decreased, while the ratio of maximum discharge amplitude on the positive half-cycle to the maximum discharge amplitude on the negative half-cycle and the ratio of the number of discharges on the positive half-cycle to the number of discharges on the negative half-cycle increase gradually, and the decrease rate with the discharge amplitude of the number of discharges which is defined in this paper becomes faster and faster.