低气压下绝缘子短波头操作冲击污闪特性

在操作冲击下绝缘子也会发生污闪，且随着海拔升高或气压降低，绝缘子操作冲击污闪电压还将降低。为满足我国高海拔地区污秽绝缘选择的需要，文章在人工气候室模拟不同海拔条件下的低气压，通过试验研究了清洁和染污7片串XP-160绝缘子在短波头操作冲击下的污闪特性，得出了盐密、气压、温度对污秽绝缘子50%操作冲击闪络电压影响的关系式，确定了三者的影响特征参数。研究结果表明，与清洁绝缘子的干闪和雾闪电压相比，污秽绝缘子在操作冲击下的污闪电压明显降低，因此工程设计时应考虑污秽绝缘子的操作冲击放电特性。

Insulator Pollution Flashover Performance Caused by Steep-Front Switching Impulse Under Low Air Pressure

The flashover of polluted insulators under switching impulse may happen. Along with increasing attitude or decreasing air pressure,the pollution flashover voltage of insulator will descend. To meet the demand of selecting insulation for polluted high attitude localities in China,the authors simulated low air pressure under various attitudes by phytotron,through the experiments the pollution flashover performances of both clean and polluted insulator strings composed by seven pieces of XP-160 insulator under steep-front switching impulse are researched,herefrom the relations to express the impacts of salt deposit density,air pressure and temperature on 50% switching impulse flashover voltage are obtained and the impacting characteristic parameters of these three factors are determined. Research results show that comparing with dry-flashover voltage fog-flashover voltage of clean insulator,the pollution flashover voltage of polluted insulator under switching impulse decreases evidently,thus the switching impulse discharge characteristic of polluted insulator should be considered during the engineering design.