1.Introduction
An oil-immersed transformer is a type of power transformer that uses insulating oil as both a cooling medium and an electrical insulator. It is widely used in power distribution and transmission systems due to its high efficiency, reliability, and ability to handle high voltages.
2.Core Components
- Core: Made of laminated silicon steel to reduce eddy current losses.
- Winding: Primary and secondary coils (copper or aluminum) wound around the core.
- Insulating Oil: Mineral oil or synthetic ester oil for insulation and heat dissipation.
- Tank: Sealed enclosure housing the core, winding, and oil.
- Conservator: An auxiliary tank to accommodate oil expansion/contraction.
- Buchholz Relay: A safety device detecting gas accumulation due to internal faults.
- Cooling System: Radiators or fans to enhance heat dissipation.
3.Working Principle
(1)Electromagnetic Induction
- When AC voltage is applied to the primary winding, it creates an alternating magnetic flux in the core.
- This flux induces a voltage in the secondary winding Faraday’s law of induction .
(2)Insulation & Cooling
- The insulating oil prevents arcing between winding and the grounded tank.
- Oil circulates naturally (or via pumps) to transfer heat from the core/winding to radiators, maintaining optimal temperature. Protection Mechanisms
(3)Buchholz Relay:
- Triggers alarms or disconnects the transformer if gas (from oil decomposition) is detected.
- Pressure Relief Valve: Releases excess pressure to prevent tank rupture.
(4)Advantages
- High efficiency (up to 99%).
- Effective cooling extends lifespan.
- Suitable for high-voltage applications (e.g., 11kV to 400kV).
(5)Applications
Power grids, substations, industrial plants, and renewable energy systems.
Conclusion ：Oil-immersed transformers ensure efficient voltage transformation while relying on oil for insulation and cooling. Their robust design makes them indispensable in modern power systems.
Post time: Jun-16-2025
