标题：PD Classification in Oil-pressboard Insulation by Simulating a Needle-plate Model with plus DC Voltage
作者：Li, Simeng; Li, Qingquan; He, Dongxin
作者机构：[Li, Simeng; Li, Qingquan; He, Dongxin] Shandong Univ, Sch Elect Engn, 17923 Jingshi Rd, Jinan 250061, Shandong, Peoples R China.
通讯作者：Li, QQ;Li, Simeng
通讯作者地址：[Li, QQ]Shandong Univ, Sch Elect Engn, 17923 Jingshi Rd, Jinan 250061, Shandong, Peoples R China.
来源：IEEE TRANSACTIONS ON DIELECTRICS AND ELECTRICAL INSULATION
关键词：partial discharges; composite insulation; signal analysis; space charge;; electric fields; streamer evolution
摘要：The DC voltage related partial discharge (PD) classification in solid dielectrics under a uniform electric field has been studied, but it is more complicated in liquid-solid composite insulation under a highly non-uniform electric field. Therefore, PD pulse waveforms and PD channel shapes in oil-pressboard insulation were investigated by simulating a needle-plate model with a positive DC voltage via pulse current method. The elements of PD can be classified in order of ionizing intensity strength as corona, tree-like PD, single-streamer PD, or multi-streamer PD according to the discharge channel shape. The corona pulses are sharply oscillating, whereas the other types of PD can generate unimodal pulses with no over-zero oscillation. A finite element analysis reveals the PD types are related to the charge quantity at the oil-pressboard interface, which influences the streamer evolution by distorting the space electric field. This study uncovers the physical process during PD in oil-pressboard insulation and provides basis for explaining the PD mechanism.