Transformer

Transformer Knowledge Points:

1. Differences Between Dry-Type and Oil-Immersed Transformers:

Difference    Oil-Immersed Transformer    Dry-Type Transformer

1. Different Appearance    Oil-immersed only shows the transformer casing    Dry-type directly reveals the core and windings

2. Different Lead Forms    Oil-immersed transformers mostly use porcelain bushings    Dry-type transformers mostly use silicone rubber bushings

3. Different Capacity and Voltage

Oil-immersed transformers can achieve all required capacities and cover all voltage levels.

Dry-type transformers are generally suitable for distribution applications, typically with capacities below 2000kVA and voltages at or below 10kV.

4. Insulation and heat dissipation:

Oil-immersed transformers rely on insulating oil for insulation. Heat generated by the windings is transferred to the transformer's radiator fins via circulating insulating oil for dissipation.

Dry-type transformers typically use resin insulation and rely on natural air cooling. Larger capacities may employ forced air cooling via fans.

5. Application Environments

Oil-immersed transformers, due to potential oil spray or leakage causing fires in case of failure, are mostly used outdoors where space is available for digging an “accident oil pool.”

Dry-type transformers are mostly used in locations requiring “fireproofing and explosion-proofing,” and are generally suitable for large buildings and high-rise structures.

6. Different Load-bearing Capabilities

Oil-immersed transformers have better overload capacity.

Dry-type transformers should generally operate within their rated capacity.

7. Cost Differences

Dry-type transformers carry a significantly higher purchase price than oil-immersed types. Oil-immersed transformers are less expensive than dry-type.

2. Copper foil is typically used in low-voltage transformers.

Copper wire is generally used in high-voltage transformers.

3. The transformer body consists of windings (insulating paper plus enameled wire/copper foil) + iron core.