Trafo

Trafo (Transformer) – Comprehensive Guide

1. Main Types of Trafo

(1) By Cooling Method

• Oil-Immersed Trafo

• Uses insulating oil for cooling, suitable for high-voltage and high-capacity applications (e.g., grid substations).

• Common Models: ONAN (natural cooling), ONAF (forced air cooling), OFAF (forced oil and air cooling).

• Dry-Type Trafo

• Oil-free design, insulated by air or resin, ideal for fire-sensitive environments (e.g., hospitals, data centers).

• Common Models: SCB (epoxy resin-cast), SG (open-type).

(2) By Application

• Distribution Trafo

• Voltage levels: 10kV/0.4kV, used for end-user power supply (e.g., residential areas, factories).

• Power Trafo

• Voltage levels ≥110kV, used in transmission networks (e.g., substation main transformers).

• Special Trafo

• Includes rectifier transformers (for electrolysis), mining transformers (explosion-proof design), etc.

                     

2. Key Specifications

3. Applications

• Power Systems: Voltage step-up/down, grid interconnection.

• Industrial: Power supply for motors, furnaces (custom impedance may be required).

• Renewable Energy: PV/wind grid integration (must withstand harmonics).

• Rail Transit: Traction transformers (25kV/50Hz).

4. Selection Guide

• Indoor Installation: Prefer dry-type (fireproof) or fully sealed oil-immersed.

• Outdoor Installation: Oil-immersed (protection class ≥IP55).

• High Load Fluctuations: Choose models with strong overload capacity (e.g., ONAF cooling).

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5. FAQ

Q: How to choose between oil-immersed and dry-type transformers?
A: Oil-immersed offers lower cost and higher capacity but requires fire protection; dry-type is safer for confined spaces.

Q: How to calculate required capacity?
A: Sum all load power (kVA) and reserve 20%~30% margin.

Q: How to reduce transformer noise?
A: Select low-noise designs (e.g., step-lap core) or install soundproof enclosures.