The production process of coal preparation plant was affected by high current short circuit fault in production mine, the distribution of the coal preparation plant was caused by the loss of power line lightning fault, the tripping of the motor was caused in the course of production, the equipment was stopped working in a large area. In order to effectively solve the problem of voltage sag and tripping, the dynamic voltage restorer combining with complete compensation method and the in-phase compensation method ( DVR ) were selected. Field application results show that the utility model can reliably compensate the voltage drop caused by the underground high current short circuit under the condition that the balance voltage and the unbalanced voltage fall, the normal and orderly production of the coal preparation plant can effectively be guaranteed.