Dry-type transformers adopt an oil-free insulation structure, with air or solid insulating materials (such as epoxy resin) as the cooling and insulating medium. It has prominent advantages such as safety and environmental protection (fire and explosion proof), maintenance-free (no oil treatment and detection required), reliable operation, and convenient installation (no oil pit required, low fire protection requirements). It is especially suitable for places with strict requirements on safety, environmental protection and space such as high-rise buildings, subways, airports, hospitals, data centers, industrial and mining enterprises. It is a high-efficiency, reliable and green core equipment for electric energy conversion in modern power distribution systems.