中文摘要：

为了对实际高海拔下复合绝缘子耐污性能（污闪和污雨闪）及其影响因素进行系统研究，在高海拔（1970m）地区，对影响复合绝缘子直流污闪特性的因素，如盐密、灰密、盐成分和污秽上下表面分布等进行了系统研究，同时对直流污雨闪性能受盐密和淋雨量的影响进行了对比试验。试验发现，直流污闪电压与盐、灰密均呈负幂函数关系，盐、灰密越大，直流污闪电压越低；复合绝缘子直流污闪电压随着盐混合物中CaSO4所占比例的增大而升高；污秽上下表面分布越不均匀，污闪电压越高。同时，盐密对直流污雨闪电压的影响亦符合负幂函数关系；污雨闪电压随淋雨量的增大而降低。该结果可直接作为高海拔地区直流输电工程外绝缘设计的试验参考。

英文摘要：

In order to research the pollution resistance performance （pollution flashover and raining flashover） of composite insulator and its influential factors for composite insulator in natural high altitude in China and aboard, based on these pollution flashover tests and raining flashover tests of contaminated composite insulators under different conditions （component of soluble material, distribution, ESDD and NSDD） in natural high attitude （1970 m）, the influence of pollution conditions on DC pollution flashover performance was analyzed systematically. The influential factors （ESDD and different precipitation rates） of raining performance were comparatively analyzed. The results show that, pollution flashover voltage decreases with the increase of ESDD by a negative power function as well as NSDD. The increasing percentage of CaSO4 leads to the higher DC contamination flashover voltage. The relationship between flashover voltage and non-uniform pollution ratio of up-and-down surface is presented. The experimental results also indicate that the relationship between ESDD and raining flashover voltage obeys negative power function and raining voltage decreases with the increasing precipitation rate. These results and conclusions can be used in the design of DC transmission line in high altitude.