Cooling method of oil-immersed transformer:

Oil Natural Air Natural (ONAN)：The working principle of oil-immersed self-cooling is to use the natural convection of oil to drive the heat generated by the transformer to the surface of the oil tank wall and the position of the heat dissipation pipe, and then dissipate the heat under the action of air convection and air heat conduction. There is no specially prepared cooling equipment for such a cooling system.

Oil Natural Air Forced (ONAF)：On the basis of the working principle of oil-immersed self-cooling, some fans are installed on the wall of the oil tank or the heat dissipation pipe, so that the transformer can be cooled by the fan blower. After installing the fan, the capacity of the transformer and the working load can be increased by nearly 35%.

Oil Forced Air Forced (OFAF)：Forced oil circulation air cooling system is used for large capacity transformers. This cooling system is based on the oil-immersed air-cooled type, and a submersible pump is installed on the connecting pipe between the main casing of the oil tank and the radiator with fan (also known as the cooler). When the oil pump is running, the oil in the forced oil tank is sucked into the radiator from the upper part, and then enters the oil tank from the lower part of the transformer to realize forced oil circulation. The cooling effect is related to the oil circulation rate.

Oil Natural Water Forced (ONWF)：Use the oil pump to drive it into the cooler and then repeatedly make it into the oil tank. The oil cooler needs to be made into some special shapes that are easier to dissipate heat, so that the medium can be cooled by the blowing effect of the electric fan, thereby taking away the heat generated by the transformer. If such a heat dissipation method triples the speed of oil circulation, it can increase the capacity of the transformer by nearly 30%.

Oil Directed Air Forced(ODAF)：A cooling method that uses forced oil circulation to make cold oil pass through the winding and the inside of the core along a certain path to improve heat dissipation efficiency.

Oil Directed water Forced(ODWF)：This method is to use the oil pump to force the oil to accelerate the circulation, and to dissipate heat through the water cooler to cool the transformer oil.

oil immersed self cooled transformer