Transformer Oil

Transformer oil consists of mineral oil, which means it is originally derived from petroleum. After being mined, this oil is refined to produce a clear, colorless liquid, and the finished product is normally odorless as well. Although it might resemble mineral oil used for household applications, this product is actually much purer and contains few if any impurities. This means regular mineral oil should not be substituted for this type of lubricant.

Types of Transformer Oil:

There are two types of Transformer Oil, Naphthenic and Paraffinic based Transformer Oils. A comparison between the Naphthenic and Paraffinic Transformer Oil is listed below.

Sr. No.	Naphthenic Oil	Paraffinic Oil
1	Mineral insulating oil derived from special crudes containg very low n-paraffin i.e. wax.	Mineral insulating oil derived from special crudes containg substantial amount of n-paraffin i.e. wax.
2	The pour point of Naphthenic Oil is less than the Paraffinic Oil as the wax content is low.	The pour point of Paraffinic Oil is more than the Naphthenic Oil as the wax content is high.
3	Boiling point of Naphthenic Oil is around 425 °C.	Boiling point of Paraffinic Oil is around 530 °C.
4	Naphthenic Oils are more readily oxidized than Paraffinic Oils.	Oxidation of Paraffinic Oil is less.
5	Oxidation products of Naphthenic Oils are soluble in the oil.	Oxidation products of Paraffinic Oils are insoluble in the oil.
6	The oxidation of paraffin-based crudes produces an insoluble sludge, which increases the viscosity. It results in reduced heat transfer capabilities, overheating and reduced service life.	Although naphthenic oils are more readily oxidized than paraffinic but the oxidation products are soluble in the oil results in a reduction of problem.
7	Naphthenic oils contain aromatic compounds which remain fluid at comparatively low temperatures such as -40°C.