Main functions of transformer oil:

(1) Insulation: transformer oil has much higher insulation strength than air. The insulation is immersed in oil, which not only improves the insulation strength, but also protects it from dampness.

(2) cooling effect: the specific heat of transformer oil is large, and is often used as a coolant. The heat generated during the operation of the transformer makes the oil close to the core and winding heated and expanded. Through the upper and lower convection of the oil, the heat is dispersed through the radiator to ensure the normal operation of the transformer.

(3) arc suppression: in the oil circuit breaker and transformer on load voltage regulator switch, contact switching will produce arc. Due to the good thermal conductivity of transformer oil, and under the action of high temperature arc can touch a large number of gases, resulting in greater pressure, thus improving the arc extinguishing performance of the medium, so that the arc quickly extinguished.

After getting the answer from a high grade oil transformer manufacturer, you should know why oil is used in transformer.