高海拔下不同伞形结构750kV合成绝缘子短样交流污秽闪络特性及其比较

为适应高海拔污秽地区750kV线路外绝缘选择的要求，在人工气候室内模拟高海拔气压条件对三伞五组合伞形和大小伞形结构的二种750kV合成绝缘子短样的污秽闪络特性进行了试验研究，分析了试品污闪电压和污闪梯度与伞裙结构的关系以及海拔高度或气压对污闪电压的影响。结果表明：合成绝缘子的污闪电压与伞裙结构有密切关系；在同样的最短干弧距离下，简单伞形结构的合成绝缘子具有更高的污闪电压和污闪梯度，对于伞形结构复杂的合成绝缘子，虽然其爬电距离提高了，但其污闪电压没有明显提高；高海拔下合成绝缘子的气压影响特征指数n大于瓷和玻璃绝缘子，并受伞裙结构形式、污秽程度的影响，且随着污秽程度增加，n逐渐减小，此外，染污方法和方式对n也有一定影响但不明显。

AC POLLUTION FLASHOVER PERFORMANCE AND COMPARISON OF SHORT SAMPLES OF 750kV COMPOSITE INSULATORS WITH DIFFERENT CONFIGURATION IN HIGH ALTITUDE AREA

For the external insulation design of 750kV AC transmission line at the Western high altitude region, laboratory investigations were carried out on the pollution flashover performance of short samples of two configurations of 750kV composite insulators in the artificial climate chamber. It analyzes the effects of the pollution severity and the altitude or atmospheric pressure on the flashover voltage(FOV) or the flashover gradient (FOG). It is shown that FOV is determined by the configuration, and the insulator with a simple design is of a higher FOV than the one with a complex design, and the special exponent n, which shows the effect of the atmospheric pressure on FOV and is dependent on the pollution severity, insulator design or the configuration as well as the polluting method, is greater than that of a porcelain or glass insulator.