In the whole process of transformer production, transformer manufacturers strictly control the moisture content of products. Generally, transformers need to go through the whole process of water removal such as gasoline liquid phase drying, vacuum pump oil pump, hot oil circulation, etc., but there will still be a certain amount of moisture. The moisture in the transformer mainly accumulates in the insulating cardboard and transformer oil, which will reduce the electrical properties of the transformer oil and the insulating cardboard, reduce the electrical compressive strength, and the penetration compressive strength will drop sharply with the increase of the moisture content. In the middle and later stages of operation, especially when the cover is repaired, it is inevitable that some moisture will invade, and the transformer oil will also dissolve moisture after thermal aging. The moisture in the body will continue to react with the insulating layer material, accelerating the aging of the insulating layer material. The results show that the aging rate of insulating paper with an ambient humidity of 2% is 11 times that of an ambient humidity of 0.
Transformer oil aging
Transformer oil can age slowly under the effects of electricity, heat and oxygen. After the aging of the transformer oil, the level of gas digestion, absorption and convergence of the transformer oil increases, resulting in the increase of the gas and viscosity in the oil.
The increase of operating viscosity will affect the heat convection and heat conduction capacity of the circulating system of the transformer. It cannot be integrated into the operating standards of the transformer, resulting in a vicious cycle, which will seriously affect the operating life of the transformer and even lead to safety accidents of machinery and equipment.
Influence of external natural forces
External factors such as wind, heavy rain, snow, hail, and earthquake disasters will also affect the service life of the transformer.