What is the function of oil inside a transformer?

Oil in transformer is used to insulate, cool, and protect the internal components of the transformer. It serves as a dielectric fluid that prevents electrical arcing by providing insulation between the energized parts and the grounded structures. Additionally, the oil dissipates heat generated by the electrical currents flowing through the transformer, ensuring efficient operation and preventing overheating. It also helps in removing moisture and potential contaminants, contributing to the overall longevity and reliability of the transformer.