As an effective means to improve the reliability of power supply, the automatic switching device of standby power has been widely used in substations. There are problems in the actual application of automatic backup power supply. It is a new type of intelligent backup power automatic switching device. The device introduces a "logic library", which integrates a large number of logic modules and time relay modules, which can be flexibly configured according to actual applications. The device automatically configures the fixed value according to the different configuration, and can simultaneously input a variety of standby automatic input methods, and automatically recognize the system operation mode, and select the corresponding standby automatic input program.