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一、单相接地故障对矿井电网的影响6kV小接地电流系统电网电气设备的相对地绝缘水平是按线电压设计的。当一相发生金属性接地时,水电系统一般不要求立即切断电源,规定要在两小时内找出故障点。钢铁、冶金系统则规定要尽量装设有选择性的零序电流保护装置,以便尽快查找故障,防止发生更严重的事故。近年来,煤矿有的选用灵敏度很高的选择性漏电保护装置(如BLD—3型,零序电压动作值为2V,二次零序电流动作值为0.15A),主要是考虑“煤
First, the single-phase ground fault on the mine power grid 6kV small ground current system The relative level of insulation of electrical equipment is designed according to the line voltage. When one phase occurs with a metallic ground, the hydropower system generally does not require an immediate power cut-off, requiring that the point of failure be found within two hours. The steel and metallurgical systems provide that as far as possible, a selective zero-sequence current protection device should be installed in order to find out the fault as soon as possible so as to prevent a more serious accident from occurring. In recent years, some selective coal mine leakage protection device with high sensitivity (such as the BLD-3 type, zero sequence voltage action value of 2V, the second zero sequence current action value of 0.15A), mainly to consider the "coal