高压柜会配有零序互感器，低压柜上有漏电开关，是检测在同一磁势环境下，流入和流出的电流产出磁势对冲后的残余电流值，当该值达到一定程度时，相关保护装置动作，告警或直接切断电源。
High-voltage cabinet will be equipped with zero-sequence transformer, low-voltage cabinet has leakage switch, which is to detect the residual current value after the inflow and outflow current produce magnetic potential Hedging under the same magnetic potential environment. When the value reaches a certain level, the relevant protection device acts, alarms or directly cuts off the power supply.