Function of transformer oil (what is the function of oil in transformer?)

What is the function of oil in transformer?    

    Oil is a very vital part of any machine, it could be a fuel oil or lubrication oil. Here we are not talking about the fuel oil. Lube Oil is the subject of this post. We all know that transformer is a stationary device means there is not any moving part which need oil. 

Hence the question raised, 

    What is the function of oil in transformer?

    Why oil used in transformer?

To know the function of transformer oil we have to go through the following parts.

The Transformer oil acts as:

• Electrical insulation media.
• Cooling media (transfer heat to radiator).
• Suppression of arcing & corona.

Electrical Insulation Media.

    The coil inside the transformer is live part and the body or casing of the transformer is dead means it is with ground potential. Therefore, insulation medium is very essential in-between this two parts. The middle space of these dead and live part is filled with oil to build up the insulation media.

Fig: Oil Immersed Transformer(Ref.- electricalbaba.com)

Cooling Media.

    Since the large quantity of current pass through the transformer coil, it will generate huge heat. This heat to be removed properly and timely to avoid any unexpected damage. The oil transfers this heat to the transformer radiator to cool the transformer.

Suppression of arcing & corona.

    Dielectric strength of the transformer oil is higher than the air that's why the arcing incident is very less in oil immersed transformer than the dry type transformer.