Three functions and performance requirements of transformer oil

Transformer Oil Uses

There are three main Transformer Oil Uses, one is insulation, the other is heat dissipation, and the third is arc suppression.

1. Insulation

Transformer oil has a much higher dielectric strength than air. The insulating material is immersed in oil, which not only improves the insulation strength, but also protects it from moisture.

There are three main Transformer Oil Uses, one is insulation, the other is heat dissipation, and the third is arc suppression.

1. Insulation

Transformer oil has a much higher dielectric strength than air. The insulating material is immersed in oil, which not only improves the insulation strength, but also protects it from moisture.

2. Heat dissipation

Transformer oil has a large specific heat and is often used as a coolant. The heat generated during the operation of the transformer causes the oil close to the iron core and windings to be heated and expanded. Through the upper and lower convection of the oil, the heat is dissipated through the radiator to ensure the normal operation of the transformer.

3. Arc suppression

On the on-load tap changer of oil circuit breaker and transformer, an arc will be generated when the contacts are switched. Because the transformer oil has good thermal conductivity, and can separate a large amount of gas under the action of the high temperature of the arc, and generate a large pressure, the arc extinguishing performance of the medium is improved, and the arc is quickly extinguished.

Causes of Oil Leakage in Oil-immersed Transformers

Transformer Oil Specification

1. The density of transformer oil should be as small as possible to facilitate precipitation of moisture and impurities in the oil.

2. The viscosity should be moderate, too large will affect the convection heat dissipation, too small will reduce the flash point.

3. The flash point should be as high as possible, and generally should not be lower than 136°C.

4. The freezing point should be as low as possible.

5. The lower the content of impurities such as acid, alkali, sulfur, and ash, the better, so as to avoid their corrosion of insulating materials, wires, fuel tanks, etc. as much as possible.

6. The degree of oxidation should not be too high. The degree of oxidation is usually expressed by acid value, which refers to the amount of potassium hydroxide (mg) required to absorb the free acid in 1 gram of oil.

7. The stability should not be too low. The stability is usually expressed by the sediment of the acid value test, which represents the oil’s ability to resist aging.