电极表面特性对甘油介质击穿特性的影响

摘要

基于几种常见的电极表面处理工艺,制作了外形一致、表面不同的砂纸打磨、羊毛抛光、金属电镀和非金属电镀四种同轴电极,对比了电极在微观下的形貌特点,通过实验研究了不同电极表面特性与甘油介质耐压的关系.搭建了基于晶闸管控制的空心脉冲变压器升压实验平台,最大输出电压 500 kV,上升时间26μs.实验结果表明:四种电极的微观形貌存在较大差异,并引起了甘油击穿特性的不同,在相同充电电压条件下,甘油的平均击穿场强为 210~260 kV/cm;与使用常规的砂纸打磨电极相比,使用羊毛抛光、金属电镀、非金属电镀电极可分别使击穿场强提高 14.51%,11.60%,19.67%,其中非金属电镀电极表面均匀程度远高于其他电极,最高击穿场强可达 288 kV/cm,比对照组平均击穿场强提高 33.09%.%Four coaxial electrodes with identical shape but different surface characteristics are made by common surface treatments,including sanding,wool polishing,metal electroplating and nonmetal electroplating.The relationship between differ-ent surface characteristics and the insulation characteristics of the glycerol medium is studied by experiments.A thyristor con-trolled air-core pulse transformer with a maximum output voltage of 500 kV and the rising time of 26μs is built.The experimen-tal results show that the four kinds of electrodes have significantly different microcosmic morphologies,resulting in different breakdown characteristics of the glycerol between the electrodes.Under the same charging voltage,the average breakdown strength of the glycerol is 210-260 kV/cm.Compared with the conventional sanded electrodes,the breakdown strength of elec-trodes disposed by wool polishing,metal electroplating and nonmetal electroplating can be increased by 14.51%,11.60% and 19.67% respectively.Due to their much higher surface uniformity,the highest breakdown strength between nonmetal electropla-ting electrodes can reach up to 288 kV/cm,which is 33.09% larger than the average value of the control group.