1. Open type: A common configuration where the transformer body is in direct contact with the surrounding air; it is suitable for relatively dry and clean indoor environments (where relative humidity does not exceed 85% at an ambient temperature of 20°C) and typically employs either natural air cooling or forced-air cooling.
2. Enclosed type: The transformer body is housed within a sealed casing and is not in direct contact with the surrounding air (due to sealing and poor heat dissipation, this type is primarily used in mining applications and is explosion-proof).
3. Cast-resin type: Uses epoxy resin or other resins for primary insulation; it features a simple structure and compact size, making it suitable for lower-capacity transformers.
