METHOD AND DEVICE FOR SWITCHING POWER SUPPLY IN ELECTRIC POWER SYSTEM

A method and a device for power supply switching in an electric power system include providing an electric power system having two power supplies, each connected to a bus through an incoming line, using the power supply currently supplying power as the main power supply, using the other power supply as a backup power supply, and respectively connecting the two power supplies to a power supply station of a higher level. Upon identifying a trigger condition, sampling of power data on the bus is started, with the trigger condition being used to decide that a fault of the electric power system is eliminated and power is lost from the main power supply. If the time period for sampling of power data reaches a preset threshold, it is determined whether the condition for circuit-closing of the backup power supply is satisfied according to each sampled power data value.