Transformer oil is one of the very important component in oil immersed transformers. The life expectancy and satisfactory operation of transformers are mainly depend on the oil in which is immersed. The transformer oil performs two very important functions. 1. It creates an acceptable level of insulation in combination with the insulating materials used in the conductors and coils. 2. It also acts as a coolant to extract heat from the core and the windings.The oil used in transformers is hydrocarbon mineral oil. It is mainly composed of four generic classes of organic compounds, aromatics, paraffins, napthenes and olefines. Transformer oil gives a better insulation when aromatics, paraffins, napthenes and olefines are present at the right proportion. For better insulation Transformer oil is desired to have more of saturated paraffins and less of aromatics, napthenes and olefines. For more stability, more aromatics and napthenes are necessary. To get both insulating property and stability at the same time, there must be an optimum mix of four organic components. This can be obtained by careful refining of crude oil. Vegetable and animal oils form fatty acids and attack the fibrous insulating materials and hence cannot be used in transformers.

Transformer oil is one of the very important component in oil immersed transformers. The life expectancy and satisfactory operation of transformers are mainly depend on the oil in which is immersed. The transformer oil performs two very important functions. 1. It creates an acceptable level of insulation in combination with the insulating materials used in the conductors and coils. 2. It also acts as a coolant to extract heat from the core and the windings.The oil used in transformers is hydrocarbon mineral oil. It is mainly composed of four generic classes of organic compounds, aromatics, paraffins, napthenes and olefines. Transformer oil gives a better insulation when aromatics, paraffins, napthenes and olefines are present at the right proportion. For better insulation Transformer oil is desired to have more of saturated paraffins and less of aromatics, napthenes and olefines. For more stability, more aromatics and napthenes are necessary. To get both insulating property and stability at the same time, there must be an optimum mix of four organic components. This can be obtained by careful refining of crude oil. Vegetable and animal oils form fatty acids and attack the fibrous insulating materials and hence cannot be used in transformers.