Abstract: Abstract: The transformer is a very critical device in the power system, and its safe operation is very important to the power system. The operational safety of the on-site cooler control cabinet directly affects the service life of the transformer. However, there will be various faults in the control cabinet during the operation of the transformer. The "General Regulations for Substations" requires that the maximum allowable operating time of the main transformer cooler under rated load shall not exceed 20 minutes. If the cooler operation is not restored within 20 minutes, it will directly cause the main transformer to trip. To this end, we developed a device that can quickly restore normal operation after a failure of the main transformer cooler control system, and can accurately collect and analyze the real-time operating data and on-site operating conditions of the main transformer cooler system after docking, and make intelligent decisions. The main transformer cooler is switched on and off, and an alarm can be issued when the cooler or the docking box fails. Key words: air-cooled；quick docking；transformer