What properties make mineral oil suitable for transformer insulation and cooling?

Mineral oil is widely used because it provides good dielectric strength, low electrical conductivity, and stable insulating performance when dry and clean. It also has favorable viscosity for circulation, high specific heat relative to gases, and good thermal conductivity for heat removal from windings and core. Mineral oil can be inhibited to slow oxidation and sludge formation. It is compatible with cellulose insulation and supports long term service when maintained through moisture control, filtration, and periodic condition testing.