Dry-type transformers are only used indoors. If they are to be used outdoors, rainproof buildings need to be built. They have low loss, low noise, high short-circuit resistance, strong flame retardancy, fireproof, explosion-proof, pollution-free, high temperature resistance, good moisture resistance, and safe and reliable operation. They are widely used in important places such as urban power grids, high-rise buildings, business centers, theaters, hospitals, hotels, tunnels, subways, underground power stations, stations, docks, airports, combined substations, etc.