① For distribution purposes, it can be used flexibly, by installing or disconnecting some transformers and lines, and the power supply and load can be deployed to meet the distribution requirements of the system in accidental operating mode, in maintenance mode and special operating mode;② For maintenance purposes: Yes Easily shut down circuit breakers, bus bars and relay protection equipment for safety inspections, without affecting the operation of the power grid or shutting down the power supply to users;③ For expansion purposes: it can easy transition from the initial phase to its final wiring, so that during expansion and transition, primary and secondary equipment and equipments should be changed to a minimum.