Series flameproof dynamic reactive power compensation device is used in coal mine low-voltage 1140V (660V) power supply system reactive power automatic compensation of special equipment. The device can be powered with coal mine system capacity of 1600KVA less mobile substation or dry-type transformers in parallel, underground mechanized mining units for mobile substation centralized compensation can also be used in mining, tunneling, exploration, transportation and other systems supply transformer two secondary side alone compensation. The main features of the device are: real-time tracking of underground power supply system electrical parameters, automatic cut slip compensation according to set goals, reactive power compensation and harmonic pollution control, improve power quality, to achieve energy saving purposes .