I. Comparison of Dry-Type and Oil-Immersed Transformers:

1. Price: Dry-type transformers are more expensive than oil-immersed transformers.

2. Capacity: Larger capacity oil-immersed transformers are more common than dry-type transformers.

3. Dry-type transformers are used in multi-purpose buildings (basements, floors, rooftops, etc.) and densely populated areas.

4. Oil-immersed transformers are used in independent substations.

5. Transformers inside prefabricated substations are generally dry-type.

6. Temporary outdoor power supply generally uses oil-immersed transformers.

7. The choice between dry-type and oil-immersed transformers should be based on available space during construction. Oil-immersed transformers are preferable for larger spaces, while dry-type transformers are preferred for more confined spaces.

8. Oil-immersed transformers are more suitable for areas with humid and hot climates. If dry-type transformers are used, forced air cooling equipment is essential. II. Differences between Dry-Type and Oil-Immersed Transformers:

1. Appearance: The encapsulation is different. Dry-type transformers allow direct viewing of the core and coils, while oil-immersed transformers only allow viewing of the outer casing.

2. Lead Type: Dry-type transformers mostly use silicone rubber bushings, while oil-immersed transformers mostly use porcelain bushings.

3. Capacity and Voltage: Dry-type transformers are generally suitable for power distribution, with capacities mostly below 1600KVA and voltages below 10KV, although some reach 35KV. Oil-immersed transformers, on the other hand, can be made in all capacities and voltage levels. The 1000KV ultra-high voltage test line currently under construction in my country will definitely use oil-immersed transformers.

4. Insulation and Heat Dissipation: Dry-type transformers generally use resin insulation and rely on natural air cooling, with larger capacities cooled by fans. Oil-immersed transformers rely on insulating oil for insulation, and the circulation of the insulating oil inside the transformer dissipates the heat generated by the coils to the transformer's heat sink (plates) for heat dissipation. 5. Applicable Locations: Dry-type transformers are mostly used in locations requiring fire and explosion protection, and are commonly found in large and high-rise buildings. Oil-type transformers, on the other hand, are mostly used outdoors in locations with available space for constructing emergency oil tanks, as oil leaks or spills may cause fires in the event of an accident.

6. Different Load Capacities: Dry-type transformers should generally operate at their rated capacity, while oil-type transformers have better overload capacity.

7. Different Costs: For transformers of the same capacity, the purchase price of a dry-type transformer is significantly higher than that of an oil-type transformer.