Method and apparatus for switching power supplies in power system

The invention provides a method and device for switching power supplies in an electric power system, the electric power system comprises two power supplies, each power supply is connected to a bus through an incoming line, one power supply which is currently supplying power serves as a main power supply, the other power supply serves as a standby power supply, and the two power supplies are respectively connected to a power supply station of the upper level. The method comprises the steps that if a trigger condition is recognized, sampling of power data on a bus is started, and the trigger condition is used for determining that a power system fault is cleared and a main power supply loses power supply; and if the sampling time of the electric power data reaches a preset threshold value, determining whether a switching-on condition of the standby power supply is met or not according to each sampling value of the electric power data. 本发明提供一种用于电力系统中切换电源的方法和装置，所述电力系统包括两个电源，每个所述电源通过一个进线连接于一个母线，当前正在供电的一个电源作为主电源，另一个