What is the difference between an oil-immersed transformer and a dry-type transformer?

Oil-immersed transformers use insulating oil for heat dissipation and insulation, so they usually have stronger overload capability and are often used outdoors, in substations, and in higher-capacity distribution systems.

Dry-type transformers use air and epoxy resin insulation, with no oil leakage risk, making them more suitable for indoor applications such as commercial buildings, hospitals, and data centers where fire safety and cleaner operation are priorities.

In practice, selection should consider installation environment, capacity requirement, fire protection standard, and lifecycle maintenance strategy rather than only initial equipment cost.