Study on Discharge Characteristics of Multilayer Oil-paper under High Frequency Pulse Voltage

High-frequency transformers with small size and light weight have been widely concerned by researchers at home and abroad. The oil-paper insulation of high frequency transformers is affected by the high frequency pulse produced by power electronic device, which is more prone to discharge fault and insulation failure. To study the effect of high frequency pulse voltage on the discharge characteristics of oil-paper insulation, a needle plate electrode model was used to carry out the discharge experiment of different layers of oil-paper insulation samples at 1–20 kHz bipolar high frequency square wave voltage produced by high frequency power supply. The partial discharge and breakdown characteristics of oil-paper insulation under high frequency square wave pulse voltage were studied. The results show that the discharge quantity of oilpaper insulation increases greatly with high frequency pulse voltage compared with AC voltage. There is no discharge phenomenon in the process of discharge development, which is significantly different from that under AC voltage. The intensity of discharge increases under high frequency pulse voltage and its increasement accelerates the deterioration of oil-paper insulation.