高海拔地区750kV线路防污闪、防雨闪措施研究

我国第1条750kV输电线路不仅处于高海拔地区，而且该地区气候条件恶劣，环境染污问题严重。根据750kV输电线路所在的高海拔地区的气候环境特点，分析了外绝缘设备在高海拔地区的污闪问题，并通过试验证实了复合绝缘子和RTV涂料技术在高海拔低气压条件下的防污闪能力，分析了高海拔地区可能出现的气象条件对硅橡胶材料憎水性的影响，发现低温和高湿度对硅橡胶憎水性的影响比低气压的影响更显著。讨论了750kV变电设备上可能出现的雨闪问题，提出了提高相关设备防雨闪能力的建议措施。

Study on methods of preventing pollution flashover and wet flashover for 750 kV lines in high altitude area

The first 750 kV transmission line was built up in northwest China, and the most parts of this line lain in high altitude area. The artificial pollution test was carried out on a kind of 35 kV composite insulator, two kinds of cap and pin insulators and a kind of post insulator with and without RTV coating in different pressure condition corresponding to the altitude from 0 m to 3 000 m. The results show that, though the flashover voltage of composite insulator and RTV coated insulator decreases with the increase of altitude, which is similar to normal porcelain insulator, the anti-pollution flashover ability of them are much better than those of porcelain insulators. According to the latent climate and environment in high altitude area, the hydrophobicity of silicone rubber was also studied in the conditions of low temperature, low pressure and high humidity. It is found that the influences of low temperature and high humidity are much severer than that of low pressure. Further more, the paper analyzed the common characteristics of insulators, on which wet flashover happened. Some suggestions on improving the ability of preventing wet flashover were given.