Influence of insulating materials on oil-immersed transformers

Thermal stability of insulating material is the main factor affecting the life and overload capacity of oil-immersed transformer, from the aspects of manufacturing technology, physical and chemical properties, electrical properties and anti-aging ability. This article describes the high temperature solid insulation materials that can be used in oil-immersed transformers, and puts forward the problems that need to be paid attention to in the application of high temperature insulation materials in oil-immersed transformers. These insulation materials include electrical laminated wood, electrical pressboard, diamond dotted paper and so on.

Oil-immersed transformer has the characteristics of good heat dissipation, low loss, large capacity and low cost. Insulated crepe paper has become the most widely used insulation material in power grid, and its reliability is directly related to the safety and stability of power grid. The oil-immersed transformer adopts solid-liquid composite insulation structure. At present, the conventional oil-paper insulation system composed of cellulose insulating paper and mineral insulating oil is often used. The safety and reliability of the insulation system is the basic condition for the normal operation of the oil immersed transformer. In the operation process of the oil-immersed transformer, the insulation system will gradually aging due to the influence of temperature, oxygen, moisture and many other factors, among which the thermal aging is the most important factor. The thermal stability of insulating materials, such as DDP diamond dotted paper, is the main factor affecting the life load capacity and volume of oil-immersed transformers.

Scholars at home and abroad have done a lot of research on high temperature insulating materials for oil-immersed transformers. In the field of solid insulating materials, on the one hand, aromatic polyamide paper and polyamide material bonding paper have been applied in oil-immersed transformers. On the other hand, the application of polymer materials in oil-immersed transformers has received official attention, such as polyester, polycarbonate and so on. It is still an important link in the development of insulating materials to improve the aging resistance and heat resistance of insulating materials for oil-immersed transformers.