沙尘环境下绝缘子交流闪络特性及机理

AC Flashover Performance and Mechanism of Insulator in Wind Sand Environment

风沙环境下沙粒的性质和状态可对输电线路外绝缘特性产生影响,进而威胁输电线路的安全运行。以瓷绝缘子XP-70为研究对象,在沙尘模拟实验室,分别研究了风沙环境和风沙过境后沉积在绝缘子表面上的沙尘对绝缘子交流闪络特性的影响。对风沙速度、风沙带电量、沙尘沉积量等因素对瓷绝缘子闪络电压的影响规律开展了实验研究,结果表明:瓷绝缘子闪络电压随风速的增大而升高,且有风有沙时的闪络电压比有风无沙时低;同时,随着沙粒荷质比升高,绝缘子闪络电压呈降低趋势,且沙粒带负电时比带正电时的闪络电压略高;绝缘子上表面沉积沙尘后,其闪络电压随着沉积量的增加先减小后增大,存在极小值;最后,结合闪络过程和泄漏电流的分析,对风沙环境下绝缘子沿面放电机理进行了深入的探讨。

The flashover performance of insulator in sand storm can be influenced by the air condition and the characteristics of sand particle, then may bring danger to the safe operation of transmission line. Therefore, by analyzing relative literatures and the research results, and taking an XP-70 porcelain insulator as the research object, we experimentally and theoretically investigated the AC flashover characteristics regularity of the insulator in wind sand environment , and obtained the influences of wind speed, charge deposited on sand and sand quality in the flashover process. It is found that the flashover voltage of the XP-70 porcelain insulator increases with the increase of the wind speed in wind sand environment under the AC voltage, and that the flashover voltage in weather of wind dust is lower than that in the weather of wind. The flashover voltage of the XP-70 porcelain insulator decreases with the increase of the sand specific charge, and the flashover voltage of the sand with positive charge is lower than that with negative charge. When the sand particles deposit on the surface of the insulator, the flashover voltage appears to be a curve which decreases at first and then increases, and there is a minimal value. Moreover, according to the flash- over process and the change of the leakage current during the process, the flashover mechanism of the insulator was analyzed.