750 kV交流输电线路覆冰区绝缘设计

我国第一个750kV交流输电工程已经投运。由于部分线路跨越覆冰区,因此在绝缘设计上必须予以特殊考虑。文章讨论了覆冰的形成条件和影响因素,分析了影响绝缘子串覆冰闪络特性的因素,包括覆冰类型、覆冰厚度、冰水电导率、绝缘子串悬挂方式等。根据试验数据,考虑了海拔修正,给出了750kV输电线路在各个海拔高度下的覆冰区绝缘设计,如海拔高度在1000m及以下时,750kV线路V型串最小长度为6.3m,悬垂I串的最小长度为7.7m;海拔高度为1000~2000m时,V型串最小长度为6.7m,悬垂I串的最小长度为8.1m;推荐选用V型串或耐张串。

Insulation Design in Icing Areas for 750 kV Transmission Lines

The first 750kV AC transmission line in China had been put into operation. There are still several 750kV lines in planning. Because partial lines will pass though areas coated with ice, the line insulation design must be considered specially. The formation of the ice and the influence factors were discussed in this paper. Some factors which influence the icing flashover voltage of insulator strings were also discussed, including ice type, ice thickness, conductivity of ice water, suspension type, and etc. According to the testing data, considering the altitude correction, the insulation design under different altitude height of 750kV transmission lines were presented, include string length of I string and V string, the recommended suspension type was also presented.