The oil-immersed transformer is primarily composed of the following key components:

　　Iron Core:

　　Function: The iron core serves as the magnetic circuit part of the transformer, conducting and concentrating magnetic flux to achieve electrical energy conversion.

　　Material: It is typically constructed from high-permeability cold-rolled silicon steel sheets stacked together to reduce hysteresis and eddy current losses.

　　Windings:

　　Function: The windings form the electrical circuit part of the transformer, wound from copper or aluminum conductors to transmit and transform electrical energy.

　　Types: Generally divided into high-voltage windings and low-voltage windings, which are insulated from each other by insulating materials to ensure electrical safety.

　　Insulating Oil:

　　Function: Insulating oil not only acts as an insulating medium between the windings and the iron core but also serves as a cooling and heat dissipation agent. It fills the internal gaps of the transformer, enhancing its insulating properties and heat dissipation efficiency.

　　Characteristics: Insulating oil must possess good electrical insulating properties, thermal stability, and chemical stability.

　　Oil Tank:

　　Function: The oil tank is the outer shell of the transformer, housing the iron core, windings, and insulating oil, while providing necessary mechanical protection.

　　Structure: The oil tank is usually welded from steel plates, offering good sealing and strength to prevent insulating oil leakage and the ingress of external contaminants.

　　Accessories:

　　Oil Conservator (Oil Pillow): Used to regulate the volume of transformer oil to accommodate oil volume expansion and contraction caused by temperature changes.

　　Breather: Contains desiccant (such as silica gel) to absorb moisture from the air entering the oil conservator, maintaining the oil's insulating properties.

　　Explosion Vent (Safety Airway): Releases pressure when a large amount of gas is generated inside the transformer due to a fault, preventing the transformer from exploding.

　　Buchholz Relay: Monitors fault gases inside the transformer and issues an alarm or cuts off the power supply when the gas volume reaches a certain level.

　　Thermometer: Measures the oil temperature of the transformer to provide timely information on its operating status.

　　Tap Changer: Used to regulate the output voltage of the transformer by changing the turns ratio of the high-voltage windings.

　　Cooling Devices:

　　Function: Cooling devices dissipate the heat generated during the transformer's operation to maintain its normal working temperature.

　　Types: Depending on the transformer's capacity and cooling requirements, cooling devices can be natural cooling (such as radiators) or forced cooling (such as fans, oil pumps, etc.).