Why is oil used in transformers and what types are available?

Oil is used in transformers primarily for insulation and cooling purposes. It provides electrical insulation between live components and dissipates heat generated during operation. The two main types of oil used are mineral oil, derived from refining crude oil, and synthetic esters, which are biodegradable and offer better fire resistance. Each type has specific properties that cater to different operational environments and safety requirements in power transformer applications.