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矿井低压供电线路采用选择性漏电保护时,因零序电压或零序电流达不到整定值,导致选择性漏电保护不能正确动作。针对上述问题,分析了在接地故障下,发生故障时的保护安装处的负序电压和零序电压以及负序电流和零序电流之间的相位关系,负序电压和零序电压的相角差在0°～45°之间,负序电流和零序电流相角差为0°。据此提出了零序电压或零序电流达不到整定值时采用负序电压或负序电流代替零序电压或零序电流,进行零序功率方向判别,实现选择性漏电保护。
When the mine low-voltage power supply line adopts the selective leakage protection, the zero-sequence voltage or zero-sequence current can not reach the setting value, so the selective leakage protection can not operate correctly. In view of the above problems, the negative sequence voltage and zero sequence voltage, the phase relationship between negative sequence current and zero sequence current, the phase angle of negative sequence voltage and zero sequence voltage The difference is between 0 ° ~ 45 °. The phase difference between negative sequence current and zero sequence current is 0 °. It is proposed that the negative sequence voltage or negative sequence current should be used instead of zero sequence voltage or zero sequence current when the zero sequence voltage or zero sequence current can not reach the setting value, and the zero sequence power direction is discriminated to realize the selective leakage protection.