What is the composition of oil used in transformers?

The composition of oil used in transformers primarily consists of mineral oil, which is derived from refining crude oil. This mineral oil is often treated to remove impurities and enhance its dielectric properties. Additionally, transformer oil may contain additives such as antioxidants, corrosion inhibitors, and anti-foaming agents to improve performance and longevity. The specific formulation can vary depending on the manufacturer’s specifications and the operational requirements of the transformer.