What functions does electric transformer oil perform in cooling and dielectric isolation?

Transformer oil serves two critical functions. First, it provides dielectric insulation between energized components and to ground, increasing breakdown strength and reducing the risk of arcing. Second, it transports heat from windings and core to radiators or coolers, supporting stable operating temperatures and reducing insulation aging. Oil also helps suppress small discharge activity by limiting oxygen and cooling hot spots quickly. By filling voids and excluding moisture laden air, oil improves overall insulation coordination and supports long life of paper insulation and internal conductors.