What are the primary uses of transformer oil in power systems?

Transformer oil is primarily used for electrical insulation and heat removal in oil immersed transformers. It increases dielectric strength between live parts, suppresses partial discharge, and protects cellulose insulation from oxygen exposure. Oil also transfers heat to cooling surfaces such as radiators. In addition, transformer oil serves a diagnostic role, as fault generated gases dissolve in oil and are analyzed through DGA to detect internal problems before catastrophic failure occurs.