Oil Immersed Transformer

Oil-immersed transformers use oil as the primary insulation medium and rely on oil for cooling, including methods such as oil-immersed self-cooling, oil-immersed air-cooled, oil-immersed water-cooled, and forced oil circulation. The main components of a transformer include the core, windings, oil tank, oil conservator, breather, explosion-proof tube (pressure relief valve), radiator, insulating bushing, tap changer, gas relay, thermometer, and oil purifier, among others.

Between the layers of silicon steel sheets in oil-immersed transformers, due to long-term immersion in transformer oil, the oil can penetrate into the gaps, and the elasticity of the transformer oil provides a buffering effect, resulting in low noise for such transformers. However, the tap changer is located inside the oil tank, making it impossible to visually inspect the quality of the switch contacts from the outside during voltage adjustment. If the contacts fail to connect, it results in an open circuit in that phase; if the contact is poor, the switch is prone to burning out under excessive load.

Features and Applications

1. Excellent heat dissipation performance

Oil-immersed transformers use transformer oil as the heat dissipation medium, which can effectively conduct and dissipate the heat generated by the windings and core, ensuring stable operation in high-temperature environments.

2. Superior insulation performance

Transformer oil has high electrical and mechanical strength, which can effectively prevent arc discharge and protect the coils and equipment. Additionally, the windings of oil-immersed transformers use insulating oil as the dielectric medium, further enhancing their insulation performance.

3. Stable operation

Oil-immersed transformers feature high mechanical strength and excellent electrical properties, enabling them to withstand abnormal conditions such as short circuits and overloads, thus ensuring the stable operation of the power system.

4. Easy maintenance

Oil-immersed transformers have a relatively simple structure, making maintenance more convenient. Routine maintenance tasks such as regularly checking the oil level and cleaning the oil tank are sufficient to ensure the transformer’s normal operation.

5. High energy conversion efficiency

Oil-immersed transformers are manufactured using advanced electromagnetic designs and high-quality materials, offering high energy conversion efficiency that reduces energy losses and operational costs.

6. Lower cost

Compared with dry-type transformers, oil-immersed transformers have lower manufacturing costs, making them widely used in power systems.

7. Good moisture resistance

Oil-immersed transformers exhibit excellent moisture resistance, allowing them to operate stably in humid environments and reducing malfunctions caused by environmental humidity.

Usage Environment

‌Altitude‌: The altitude for using oil-immersed transformers shall not exceed 1,000 meters.

‌Maximum ambient temperature‌: Not exceeding 40°C.

‌Maximum daily mean ambient temperature‌: Not exceeding 30°C.

‌Maximum annual mean ambient temperature‌: Not exceeding 20°C.

‌Minimum ambient temperature‌: Not lower than -25°C (for outdoor type), not lower than -5°C (for indoor type).

‌Relative humidity‌: At an ambient temperature of 25°C, the relative humidity shall not exceed 90%.