As a core component in power systems, the forming process of oil-immersed transformers directly impacts their insulation performance, heat dissipation efficiency, and operational reliability. This process integrates the electromagnetic unit with insulating oil through a precise manufacturing process, creating a stable electrical device structure.
In the iron core manufacturing process, high-permeability silicon steel sheets are laminated and formed, with the laminations arranged in a crisscross pattern to reduce eddy current losses. After lamination, vacuum pressure impregnation is performed to ensure a uniform insulation layer between the core laminations. The coils are wound using copper or aluminum conductors in multiple layers using an automatic winding machine. Insulating materials such as polyimide film are placed between the layers to create a stepped capacitance distribution and improve surge voltage distribution characteristics.
Insulating oil infusion is a key forming step. The formed body is degassed in a vacuum drying chamber for 48-72 hours to reduce the moisture content to below 10 ppm. Then, highly refined mineral insulating oil is injected. A vacuum pressure impregnation process allows the oil to penetrate the micropores of the insulating material, forming a continuous insulating dielectric system. Modern processes commonly utilize a composite insulation structure combining NOMEX paper and oil, significantly improving the partial discharge inception voltage.
Strict control of sealing performance is required during the final assembly phase, employing corrugated oil tanks or capsule sealing technology to ensure isolation between oil and air during operation. Finished products must undergo a series of verification tests, including partial discharge tests, temperature rise tests, and short-circuit withstand tests. With technological advancements, new processes such as epoxy resin casting and oil-impregnated composite insulation are improving the environmental friendliness and reliability of transformers, driving the development of high-stability power equipment.