Safety isolation arc suppression and protection apparatus for power supply in mine

The utility model relates to an insulating and arc eliminating and protecting device for mine power supply safety. The device is arranged in a power supply system which transmits electricity from the mine ground to the underground. The device comprises a lead-in switch with short-circuit protection function, a thermorelay with overcurrent protection and a three-phase zero-sequence reactor, the two ends of which are connected with a regulation capacitor parallelly; the output end of the zero-sequence reactor is connected with a three-phase descent line and an underground transmission line is provided with distributed capacitance. A secondary winding of the zero-sequence reactor is connected with a leakage-protection circuit. By adopting the device the utility model not only meets the requirements that the power supply transmission to the underground from no-slip point of the direct grounding transformer is prohibited in Mine Safety Rules, but also meets the demands, set by the electricity sector, that the no-slip point of the transformer is to be directly connected with the ground in ground power supply. The device can save investments and can effectively prevent the occurrence of physical electric shock underground and the hazards from gas and dust explosion underground caused by hard arc.