All about transformer oil or transformer insulating oil

Transformer oil is used in the oil-filled transformer and in some other system, such as high voltage capacitors, fluorescent lamp reactors, circuit breakers, etc.


The basic requirement of transformer oil is that it must be stable at high temperatures, with excellent electrical insulation properties and adequate cooling properties.

The standard for transformer oil

• ASTM D3487 - 09 is the standard specification for mineral insulating oil used in electrical appliances. ASTM - American Society of Tests and Materials.

How transformer oil is used in the liquid type transformer

The core and windings of the liquid-cooled power transformer are submerged with transformer oil.

Transformer oil function

Following are the function of the transformer oil

• As a means of electrical insulation
• As a cooling medium (transfer the heat to the tank/conservator wall).
• Arc and crown suppression.