高海拔直流输电线路长串绝缘子污闪特性

随着直流输电工程在西部地区不断开工建设,高海拔地区的直流输电线路的外绝缘特性成为亟待解决的问题,而如何对直流长串绝缘子污闪电压进行海拔修正仍没有形成统一的认识.为此,开展了不同海拔高度下直流长串绝缘子污闪耐压试验并建立了直流长串绝缘子污闪模型.模型计算了绝缘子在不同海拔高度和不同污秽度下的污闪电压,并与试验结果进行了对比分析,试验结果验证了模型的适用性.由试验结果得出了污闪电压与气压可用线性关系表示,推荐了在附盐密度（salt deposit density,SDD）为0.05,0.1 mg/cm2两种典型污秽度时绝缘子的气压特征指数（n）.

Flashover Performance of Long-String Insulators of DC Power Transmission Line at High Altitude

Along with the commencement of DC power transmission projects in the western region, the external insulation of DC transmission line has become a problem at high-altitude area. However, there is no uniform understanding on how to correct high-altitude influence on the pollution voltage of DC long-string insulators. The pollution flashover test of long string insulators in high altitude was carried out and flashover model was established. The pollution voltages of insulators at different altitudes and different degrees of pollution were calculated and the data were contrasted with the test results, which verified the adaptability of the model. The linear relationship between pollution flashover voltage and atmospheric pressure was obtained through test results, and the pressure characteristic exponent n of two typical pollution （ SDD = 0.05, 0. lmg/cm2 ） were suggested.