Self-healing method for differential protection of multi-contact power supply system

The invention discloses a self-healing method for differential protection of a multi-contact power supply system, which comprises an active power supply and a standby power supply, a protection area switch capable of cutting off the active power supply or the standby power supply to supply power to a differential protection area is a to-be-operated switch, and a comparison unit calculates a difference value between a pulse corresponding to an inflow current and a pulse corresponding to an outflow current. When the difference value exceeds a threshold value, the comparison unit sends a tripping signal to cut off the switch to be operated, then the interconnection switch is closed to enable the backup power supply to supply power, and the comparison unit sends the tripping signal to the switch to be operated through the optical fiber for the switch to be operated which sends pulses to the comparison unit through the optical fiber. According to the method, rapid self-healing of other areas outside the protection