高压六氟化硫断路器触头间动态击穿特性试验研究

摘要

For the breakdown characteristics of SF6 medium between the real shape electrodes for high-voltage electrical equipment, this paper set up the experimental circuit of dynamic breakdown characteristics of gap between contacts for 126kV SF6 circuit breaker. The break-down voltages were measured during the process of circuit breakers breaking and closing under different voltage polarity and arc extinguish chamber air inlfation pressure respectively. Voltage value and corresponding opening travel of experimental breakdown point were recorded. The iftting curves of breakdown voltage under different opening travel were obtained by using power function and four order polynomial to ift the breakdown voltage value of breaking and closing process respectively. This paper gave the mathematical expression of breakdown voltage and distance between the contacts. The test results show that during the process of SF6 circuit breakers breaking and closing, the positive polar-ity breakdown voltage is greater than negative polarity of SF6 gas when the opening travel reaches a certain value and the breakdown voltage of breaking process (the average speed is 9.6m/s) is lower than that of closing process (the average speed is 4.7m/s) for the same contact gap.%针对六氟化硫(SF6)气体在高压电器设备实际形状电极间的击穿特性，搭建126kV SF6断路器触头间动态击穿特性试验回路，分别测量断路器在不同电压极性和灭弧室充气压强下分、合闸过程中触头间击穿电压，统计试验击穿点电压值和对应的开距，分别采用幂函数、四次多项式对分、合闸过程触头间击穿点电压值进行拟合，得到不同开距下击穿电压拟合曲线，并给出触头间击穿电压与开距之间的数学表达式。试验结果表明：SF6断路器分、合闸过程中，当触头间开距达到一定值后，SF6气体表现出“反极性”效应；同一开距下，分闸过程(平均速度9.6 m/s)击穿电压小于合闸过程(平均速度4.7 m/s)。