Abstract: In 380V auxiliary power system of the 300MW unit of Sichuan Guang′an Power Generation Company Limited project phase I, the configuration of some low voltage distribution equipments, such as PC, MCC and power inlet switches, was not rational, which formed hidden safety danger for the operation of the unit and its auxiliary equipments when a fault of the auxiliary power occurred. The hidden danger and hazard existing in the 380V auxiliary power system of the unit were analyzed; the optimization scheme was put forward; and safety power supply of the auxiliary power system of the unit was ensured.

Key words: auxiliary power system, distribution equipment, hidden danger and hazard, optimization scheme