工频绝缘试验恢复过电压保护装置

Restoring over-voltage protection equipment for power frequency insulation experiments

从理论分析入手,介绍了一种应用试验变压器供电的工频绝缘试验中,当试品发生闪络时的恢复过电压保护装置.该装置的主电路采用了反并联在试验变压器一次侧的快速电力电子开关,控制电路由信号输入电路、放大电路、电平比较电路、定时电路、脉冲形成电路和强触发电路等组成.当试品发生闪络或击穿时,保护装置主回路迅速将试验变压器一次侧短路,使高压侧失去能源,从而有效地抑制了闪络间隙的重燃而无法产生过电压.实际运行结果表明,该装置运行稳定,动作可靠.

When a flashover of tested equipment occurs in power frequency insulation experiments,a protection equipment of restoring over-voltage is presented in this paper based on theoretic analysis,to which the test voltage is applied from a testing transformer.The main circuit of protection equipment is a fast power electronic switch negatively paralleled on the side of test transformer primary winding,the control circuits are mainly composed of input circuit,amplifier,voltage comparator,timer,forming pulse circuit and strong trigger.When the flashover or breakdown of test equipment occurs,the fast power electronic switch (protection equipment) makes the primary winding be a short circuit and secondary winding be power off.This (equipment can) effectively restrain the flashovers and the over-voltages.The protection equipment has been used successfully on site several years.