Study on Override Trip Solutions Plan of Coal Mine Power Supply System

According to the problem of override trip accidents which happened in the ground substation caused by the faults of underground coal mine substation, a nd the override trip accidents could cause widespread blackout in underground mine, even could cause the gas accumulation. In combination with characteristics of coa I mine power supply system, the paper analyzed five reasons of override trip accidents in coal mine, which were the unreasonable setting methods, short lines, the larg e differences in the power system running mode, under- voltage protection, the no ftting between CT and the value of short- circuit current. And it introduced four typica I anti- override trip protection schemes, which were based on the theory of current longitudinal differential protection or trip interlocking or digital integrated protection or smart substation multi- area centralized control. Technical principles of four scheme were analyzed and their advantages and disadvantages were summarized from the view of application. The analysis showed that the override trip protection system based on the theory of intelligent substation centralized control had powerful functions and it was the development of coal mine power supply system in future.