1、问题的提出。掘进队经常反映掘进供电系统时常发生漏电保护不起作用的现象,有时带电部位对地哧哧冒火花也不见漏电保护起作用,而采区变电所的检漏器经多次试验又能正常动作。2、问题的所在。上述情况之所以发生,在于采区变电所内所安装的320kVA 动力变压器灼二次侧用两台低压总开关来配 1, the question raised. Tunneling teams often reflect the tunneling power supply system leakage protection often ineffective phenomenon, and sometimes live parts on the ground 哧 哧 sparks also play no role in leakage protection, and mining area substation leak detector after several tests can be normal action. 2, the problem lies. The above occurs because the secondary side of 320kVA power transformer installed in the mining area substation is equipped with two low-voltage main switches