带电盐雾环境对复合绝缘子硅橡胶材料闪络特性的影响

Effect of Charged Salt Fog Environment on Flashover Characteristics of Silicon Rubber for Composite Insulators

沿海及多雾地区,复合绝缘子可能长期运行在盐雾环境中,使得闪络电压降低,威胁电网的安全稳定运行。为研究复合绝缘子硅橡胶材料在持续盐雾环境中闪络特性的变化,人工模拟了盐雾环境,对带电不同时间后的硅橡胶材料进行了交流闪络试验,记录了闪络电压和带电期间的泄漏电流。结果表明：试品的闪络电压与带电电压值有关,带电试验中所施加的电压值越高,带电试验结束后的闪络电压越低;闪络电压随雾水电导率的增加呈负幂指数规律降低,特征指数随带电时间的增加而增加;闪络电压随带电时间的增加而降低。随着带电电压值、雾水电导率和带电时间的增加,试品表面水膜占表面积的比值和泄漏电流特征量（脉冲数量、最大脉冲幅值、累积放电量等）增加,是造成闪络电压下降的主要原因。

Long-time operation of composite insulators in salt fog environment may cause degeneration of properties and loss of hydrophobicity, degrading flashover voltage and threatening safety and stabilization of power grid. In order to study flashover characteristics of silicon rubber in salt fog environment, this paper studied the flashover characteristics of silicon rubber specimen in withstanding salt fog environment for different time, and the flashover voltage and leakage current were recorded. Results show that the flashover voltage is related to charged voltage, and the flashover voltage decreases with increase of the charged voltage. The flashover voltage has a negative exponential relationship with fog water conductivity, and its characteristic index increases with increase of withstanding time. The flashover voltage decreases with increase of withstanding time. With increase of the charged voltage, the fog water conductivity and withstanding time, increase of the ratio of water film to surface area and characteristic quantities of leakage current, such as number of pulses, maximum pulse amplitude and cumulative discharge, are the main reason for decrease of flashover voltage.