As a professional Combined Instrument Transformers manufacturer in China, Comewill would like to provide you quality Oil-immersed Transformer, which is widely used in power transmission and distribution systems due to its stable insulation performance and efficient heat dissipation.
An Oil-immersed Transformer is a power transformer in which the core and windings are fully immersed in insulating oil. The oil acts as both an insulation medium and a cooling agent, helping maintain stable electrical performance during operation.
In this type of transformer, the magnetic core forms a closed magnetic circuit, while primary and secondary windings transfer electrical energy between voltage levels. The insulating oil circulates inside the tank and carries heat away from internal components.
1. Iron Core
The core is made from laminated silicon steel sheets that form a closed magnetic circuit. Oil channels inside the structure allow transformer oil to circulate and remove heat.
2. Windings
Copper or aluminum conductors are wound into cylindrical coils. The low-voltage winding is usually placed inside and the high-voltage winding outside to maintain insulation spacing.
3. Oil Tank
The oil tank acts as the outer shell of the transformer and contains insulating oil while supporting internal components.
4. Tap Changer (Voltage Regulating Device)
Tap changers adjust the transformer ratio to maintain stable output voltage when supply voltage fluctuates.
5. Cooling System
Radiators mounted on the tank wall allow heat exchange between transformer oil and the surrounding air.
6. Oil Conservator
Also known as an oil pillow, this component compensates for oil expansion and contraction due to temperature changes.
7. Protective Devices
Gas relays and safety vents detect internal faults and release internal pressure when necessary.
8. Explosion proof pipe
It is installed on the oil tank of the transformer, and its outlet is sealed with glass explosion-proof film. When a serious fault occurs inside the transformer and the gas relay fails, the gas inside the oil tank breaks through the glass explosion-proof film and sprays out from the safety airway to prevent the transformer from exploding.
The Oil-immersed Transformer differs from dry-type transformers in several operating characteristics.
| Feature | Oil-Immersed Transformer | Dry Type Transformer |
| Cooling | Oil-based (natural or forced) | Air (natural or forced) |
| Insulation | Oil + Paper | Resin or air |
| Location | Outdoors, substations | Indoors, commercial buildings |
| Maintenance | Regular oil testing & sealing checks | Lower maintenance |
| Fire Hazard | Higher (without special oil) | Lower |
| Cost | Lower initial cost | Higher initial cost |
