Auxiliary machine tripping control system under low-load working condition of thermal power plant

The utility model discloses an auxiliary machine trip control system of a thermal power plant under a low load condition, which comprises a first controller, a first parameter input module and a plurality of unit sub-control units, and each unit sub-control unit comprises a coal mill detection terminal, a primary fan detection terminal and an execution terminal; the coal mill monitoring terminal comprises a current transformer, a first switching circuit, an electric energy metering chip, a first controller, a power supply module, a clock module, a first coal mill state monitoring module and a second coal mill state monitoring module, and the current transformer is connected with a coal mill motor. According to the utility model, the coal mill and the primary fan are continuously assigned to supplement the output, and the coal mill fault is divided into a first-stage fault and a second-stage fault by considering the operation condition of the auxiliary machine, so that the cascading trip of the primary fan is