Dry‑type transformer-XinYa China manufacturer

Oil-Immersed Transformer: Technical Guide for Reliable Power Distribution

An oil-immersed transformer is an electrical transformer that uses insulating oil as the primary dielectric and cooling medium. It is widely used in utility substations, industrial power systems, renewable energy stations, outdoor distribution networks, and medium to high voltage applications. The insulating oil surrounds the core and windings, providing effective electrical insulation while transferring heat to the tank surface, radiators, or cooling circuits. The core components include a laminated steel core, copper or aluminum windings, a steel tank, insulating oil, bushings, radiators, a conservator, a breather, pressure relief devices, temperature monitoring instruments, and protection relays. The oil improves dielectric strength between live parts and helps dissipate heat generated during operation. Sealed tank designs or nitrogen cushion systems can reduce oil oxidation and moisture absorption, supporting longer insulation life and more stable performance. Oil-immersed transformers are available as distribution transformers and power transformers, and can be configured for single-phase or three-phase systems. Common cooling methods include ONAN, ONAF, OFAF, and ODAF, selected according to rated capacity, load characteristics, and site conditions. They are particularly suitable for outdoor installation, continuous heavy-load operation, and environments where efficient cooling and high short-circuit withstand capability are required. Because the oil is flammable, installation must follow fire safety rules, environmental requirements, and applicable electrical standards. Key technical parameters include rated power, primary and secondary voltage, frequency, impedance, vector group, insulation level, temperature rise, no-load loss, load loss, efficiency class, and short-circuit withstand capability. Proper selection should consider load profile, ambient temperature, altitude, humidity, fault level, and grid connection requirements. Routine maintenance should include oil testing, dissolved gas analysis, insulation resistance checks, cooling system inspection, leakage inspection, tap changer verification, and grounding integrity checks. When correctly specified and maintained, an oil-immersed transformer provides stable and efficient voltage transformation for long-term power distribution.

China XINYA Power Cables Co., Ltd Email: [email protected] Email: [email protected] whatsapp: +86 15289885778 Website: https://www.supplytransformer.com