不同微槽结构绝缘子真空沿面闪络特性

针对单极性脉冲电压下不同微槽结构绝缘子真空沿面闪络特性开展实验研究。根据二次电子运动特性,设计了多种微槽宽度,对比了微槽结构和平面结构的绝缘子耐压特性差异。槽宽为1mm的微槽样品耐压水平与平面结构样品耐压水平相当,槽宽小于1mm的样品组耐压水平均高于平面结构样品,最高电压提高倍数约为1.4,说明一定尺寸范围内的微槽设计将提高绝缘子真空耐压水平。通过电场强度计算分析微槽结构对二次电子运动的影响过程可知,较大的微槽宽度可使电子限制在槽内运动,较小的微槽宽度将抑制初始电子的发展,最终二者都能达到抑制闪络的目的。通过显微镜观测各组样品表面特征,材料表面微观缺陷将可能降低材料耐压水平。

Characteristics of grooved insulator flashover under pulsed voltage

The characteristics of grooved insulator flashover under pulsed voltage are discussed in this paper. The groove widths are determined by the secondary electron emission trajectory. The experiments results show that the flashover voltages increased while the insulator samples with 0.05 mm, 0.1 mm, or 0.7 mm wide grooves were used and the biggest voltage multiple was 1.4. The samples with 1 mm wide grooves had the same flashover voltage level as the flat ones. It is concluded that proper grooves design could increase the insulator flashover level by preventing the development of the secondary electron emission avalanche. Mechanism of inhibition was analyzed with calculation of electric field strength on the surface of insulator. Wider grooves, would trap the electrons and narrower ones would inhibit the motion of the initial electrons. Comparing the samples surface micrograms, a conclusion was given that the surface micro-flaw would drop the insulator flashover level.