What is the difference between the insulation materials of dry-type transformers and oil-immersed transformers?

General oil-immersed transformer insulation is Class A insulation. It consists of natural textiles such as wood, cotton, paper, fiber, textiles based on acetate and polyester amine, and plastics that are easy to thermally decompose and have a low melting point. In mineral oil, or impregnated with oleoresin compound adhesive, its limit working temperature is 105 ℃; dry-type transformers are usually used with H-level insulation materials, that is, mica products without reinforcement or with inorganic materials as reinforcement, thickened Grade F materials, composite mica, silicone mica products, silicone organic paint, silicone organic rubber polyimide composite glass cloth, composite film, polyimide paint, etc., the limit working temperature is 180 ℃ .