The utility model discloses a novel autoeclosing device uses on the overhead transmission line who has two side powers, and this overhead transmission line has a M side power and N power that inclines, M side power one end is connected with first circuit breaker one end, and the other end is connected with a voltage transformer who is used for measuring M side power bus voltage, the first circuitbreaker other end is connected with the 2nd voltage transformer who is used for measuring M side power supply circuit side voltage, a voltage transformer and the 2nd voltage transformer's the other end all is connected with first synchronous voltage detector one end, the 2nd voltage transformer other end still is connected with the one end of low voltage detect ware, first synchronous voltage detector and low voltage detector's the other end all is connected with OR circuit one end. Compared with the prior art, the utility model discloses the ability effective control recloses the normal workof circuit, is convenient for realize the remote automation monitoring and control in power station.