The Experimental Study On The Characteristics Of Partial Discharge Under X-ray's Irradiation

Based on large power transformer's insulating structure, two test models were built for producing partial discharges in solid and in transformer oil. The effect of X-ray's irradiation on the characteristics of partial discharges was investigated experimentally. The research results indicate when the voids are subjected to X-ray's irradiation, inception voltages of partial discharges are reduced and the repetition rate and the maximum amplitude of discharge pulses are increased due to X-ray ionizing in voids. This effects is more apparent as the diameter of the voids decreases and the number of voids increases. In our test, It is shown that the X-ray's irradiation has no effect on the partial discharges in voids when the diameter of void is larger than 5 mm. For the partial discharges in oil, the repetition rate and the maximum amplitude of discharge pulses are increased under X-ray's irradiation, which are caused by ionizing the gas from oil discharges and by surface electron emission on the electrode's surface. But X-ray's irradiation has no effect on the inception voltage of the partial discharge in oil. In addition, the location on the partial discharge site is preliminarily explored by using X-ray's effect on partial discharge. The conclusion of this thesis provides experimental basic for the practical application of X-ray in power transformer's partial discharge test.