The disclosure provides a method for fast reconfiguration of power supply grid in tens of milliseconds after power grid failure. The master station of fast reconfiguration of power grid concentrates the network status information from the client stations at transformer substations or power plants, and compares it with the built-in control strategy table which deals with possible faults. When an expected power gird disconnection fault is detected, the pre-start switch-on instruction is sent to the client stations with multiple breakers which can reconnect the grid. When the fault is cleared, the client stations shall identify the fault clearing time according to the local information, and send the instruction of synchronous switch-on to the corresponding local breakers which can reconnect the separated grids. At the same time, the master station independently monitors the removal of the fault, and sends the backup switch-on signal with synchronism check to the corresponding breakers which can reconnect the separated grids. Based on the above mechanism, the disconnected grid can be reconnected within 150 ms after disconnecting. After the interconnection of the grid is restored, the breakers that form the electromagnetic ring network switch off.