据考察，煤矿井下低压电网所发生的电气故障，70％以上属于漏电故障，传统的措施是采用漏电保护的办法。当电网发生漏电或接地故障时，保护设备通过对电网绝缘状态或电气参数（主要是绝缘电阻）的监测，作用于债电开关，引起债电开关跳闸，从而切断电源达到保护的目的。为此对 According to the inspection, low voltage power grid underground coal mine occurred in the electrical fault, more than 70% are leakage fault, the traditional measure is to adopt leakage protection approach. When the power grid leakage or ground fault, the protection of equipment through the grid insulation status or electrical parameters (mainly insulation resistance) monitoring, acting on the debt switch, causing the debt switch, thus cutting off the power to achieve the purpose of protection. For this right