MOV在交直流电压下耐受能力的试验研究

MOV是限压型SPD的核心器件。限压型SPD在各种非正常工作情况下会出现温度持续上升,引发MOV热崩溃后导致SPD故障,严重时会引发火灾事故。利用热稳定试验箱和压敏电阻直流参数仪进行了多组实验,对试验数据进行了对比分析,结果表明:MOV在交直流电压下的耐受能力主要与MOV的热容量(能量吸收能力)和热阻(散热能力)有关;直流电压下MOV功率损耗产生的热量大于交流电压下产生的热量,其主要原因是直流电流下MOV的荷电率高于交流电压下的荷电率。

The Experimental Study on the Resistance Ability of MOV under AC/DC Voltage

MOV is the core component of voltage limiting SPD.Temperature of the voltage limiting SPD will increase consistently in any abnormal working conditions.It can result in MOV thermal runaway,and then cause SPD faults,or even fire.Several sets of test were conducted by using thermal stability instrument and DC parameter instrument of voltage-dependent resistor.The results of comparison and analysis of test data show that the resistance ability of MOV under AC/DC voltage is mainly related to thermal capacity(the energy absorption capability) and thermal resistance(the heat dissipation capability) of MOV.The heat produced by power loss of MOV under DC voltage is greater than that under AC voltage,which mainly because the electric charge rate of MOV under DC voltage is higher than that under AC voltage.