Insulating oil may come into contact with air during operation and gradually absorb moisture from the air, thereby reducing its insulation performance. At the same time, insulating oil may also absorb and dissolve a large amount of air. Due to the frequent operation of oil at high temperatures, the oil comes into contact with oxygen in the air, generating various oxides. These oxides are acidic and can easily corrode the metal and insulation materials inside the transformer, increase the dielectric loss of the oil, reduce the insulation strength, cause flashover inside the transformer, and easily cause breakdown of the winding and the shell.