The submersible oil pump is installed in the middle of the oil inlet pipe of the cooler. Its function is to force the insulating oil of the main transformer into the cooler and help the insulating oil in the transformer form an oil flow. Engine bearing cooling and lubricating oil. The starting signal of the submersible pump with “forward” regulation is sent by the voltage transformer at the low voltage side of the main transformer, while the starting of the standby pump is mainly determined by the winding temperature, maximum oil temperature, flow meter and flowmeter. When the submersible fails during platform operation, it will start.