Abstract: With the continuous development of urban scale and the increasing demand for power supply reliability from social development, automatic switching devices are installed in 110 kV substations. The use of self switching devices can improve the power supply reliability of the power system. This improves the reliability of user load power supply. At the same time, it can also simplify relay protection and save construction investment. This article mainly introduces the principle of the backup power automatic switching device and the configuration and operation of the automatic switching device under different wiring methods in 110 kV substations. Provide relevant guidance for the reliable and stable operation of the automatic switching device.