Why is oil used in transformers?

Oil is used in transformers primarily as a coolant and insulator. As electrical transformers operate, they generate heat due to the resistance of the conducting materials and magnetic losses in the core. The oil absorbs this heat and dissipates it to the surrounding environment, which helps maintain an optimal operating temperature for the transformer.

In addition to its cooling properties, the oil also acts as an insulator. It provides electrical insulation between the live parts of the transformer and its casing, preventing short circuits and ensuring the safe operation of the device. The insulating properties of the oil ensure that the voltage levels can be maintained safely, thus protecting both the transformer and the system it is integrated into.

The other options presented do not accurately represent the role of oil in transformers. For example, oil does not increase voltage or directly enhance conductivity; instead, it serves to protect and maintain the transformer's operational integrity. Furthermore, while energy storage is a function associated with some other electrical components, it is not relevant to the use of oil in transformers.