温度对乙丙橡胶绝缘表面沿面放电特征的影响

Effects of Temperature on Surface Discharge Characteristics of Ethylene Propylene Rubber Insulation

为了评估温度对乙丙橡胶绝缘表面沿面放电特征的影响,搭建了变温沿面放电试验系统,测量了不同温度下的沿面放电起始放电电压、熄灭电压及闪络电压。研究了不同温度下乙丙橡胶表面从起始放电到闪络过程的沿面放电特性,分析了放电次数、起始放电相位、平均放电功率和放电电流等随温度和电压幅值的变化规律。结果表明:乙丙橡胶表面的沿面放电过程与温度密切相关,随着温度的升高,沿面放电起始电压与熄灭电压均呈减小趋势,闪络电压呈先增大后减小的趋势;放电次数、平均放电电流和放电功率均逐渐增大,正、负半周放电相位左移;随着温度升高,同一电压下的平均放电电流和放电功率相差增大,负半周的平均放电电流和放电功率始终小于正半周。根据放电过程中放电功率和放电电流的变化趋势,可将放电过程分为4个阶段:放电起始阶段、放电发展阶段、放电相持阶段、临近闪络阶段,为不同温度下乙丙橡胶沿面放电的特征识别提供了理论依据。

In order to investigate the effects of temperature on the surface discharge characteristics of ethylene propylene rubber（EPR）, a variable temperature surface discharge test system was built, and the initial voltage, extinction voltage, and flashover voltage of surface discharge were measured at different temperature. The surface discharge characteristics of EPR were studied from initial discharge to flashover at different temperatures, and the variation law of discharge times, initial discharge phase, average discharge power, and discharge current with temperature and voltage amplitude were analyzed. The results show that the surface discharge process of EPR is closely related to temperature. With the increase of temperature, the initial voltage and extinction voltage decrease, while the flashover voltage increases at first and then decreases; the discharge times, average discharge current, and discharge power increase,and the discharge phase of positive and negative half cycle move to the left. As temperature increase,the difference between the average discharge power and current under the same applied voltage becomes larger, the average discharge current and discharge power in the negative half cycle are always less than that in the positive half cycle. According to the variation trends of discharge power and discharge current, the discharge process is divided into four stages： initial stage, growing stage, stalemating stage, and coming to flashover stage, and the results provide theoretical basis for recognizing the surface discharge of EPR under different temperatures.