Radiastar Factory-Supplied Pressed-Steel Panel Radiators for 220kV / 120MVA Transformers
Radiastar supplied a customized pressed-steel panel radiator system for a 120 MVA, 220 kV oil-immersed power transformer.
For high-capacity transmission transformers, the radiator system must provide sufficient heat dissipation under both ONAN (Oil Natural Air Natural) and ONAF (Oil Natural Air Forced) cooling conditions.
Based on the transformer cooling requirements, installation space and mechanical configuration, Radiastar recommended a 520 mm wide removable panel radiator with approximately 2,600 mm center distance.
The radiator is designed for vertical installation and can be equipped with forced-air cooling fans for ONAF operation.
| Parameter | Specification |
|---|---|
| Transformer Capacity | 120 MVA |
| Voltage Class | 220 kV |
| Cooling System | ONAN / ONAF |
| Radiator Type | Pressed-Steel Panel Radiator |
| Radiator Arrangement | Removable Type |
| Radiator Width | 520 mm |
| Center Distance | 2,600 mm |
| Cooling Elements | 22 fins / radiator |
| Fin Pitch | Approx. 50 mm |
| Fin Height | Approx. 2,600 mm class |
| Material | Cold-Rolled Carbon Steel |
| Typical Plate Thickness | 1.0–1.2 mm |
| Fan Cooling | Forced-Air Cooling |
| Installation | Vertical |
| Connection | Top & Bottom Header with Flange |
| Application | 220kV / 120MVA Oil-Immersed Power Transformer |
A 120 MVA, 220 kV transformer generates considerable heat during continuous operation, particularly under high-load conditions. The transformer radiator therefore plays an important role in maintaining the winding and insulating-oil temperature within the required operating range.
For this application, Radiastar selected a pressed-steel panel radiator configuration with:
The configuration provides a large effective heat-transfer surface while maintaining a practical mechanical structure for transportation, installation and maintenance.
The radiator system is designed to support two operating conditions.
Under ONAN operation, transformer oil circulates naturally through the radiator due to temperature differences.
Hot oil from the transformer tank enters the upper radiator header. As the oil flows through the radiator panels, heat is transferred from the oil to the steel radiator surface and then dissipated into the surrounding air.
The cooled oil returns to the transformer tank through the lower header.
When transformer loading increases, additional cooling capacity can be achieved by installing axial cooling fans beneath or around the radiator bank.
The forced airflow increases the heat-transfer rate across the radiator surface, allowing the transformer to operate at a higher load without relying only on natural air convection.
For a 120 MVA transformer, the ONAN/ONAF configuration provides greater operational flexibility between normal loading and higher-load conditions.
Radiastar’s pressed-steel panel radiator uses formed steel cooling panels connected to upper and lower headers.
The approximately 2,600 mm radiator height class provides a relatively large heat-dissipation surface while the 520 mm panel width provides a practical balance between thermal performance, mechanical strength and installation space.
The approximately 50 mm fin pitch is also suitable for maintaining airflow passages between adjacent cooling elements.
The removable construction provides additional advantages for large power transformers:
Radiastar is not only a transformer radiator trading company. Radiastar is a transformer component manufacturer with its own radiator production capability.
The company has been engaged in transformer-related manufacturing since 1958, with manufacturing processes developed for industrial applications.
For transformer radiator production, the manufacturing process can cover:
Steel sheet preparation → Panel forming → Welding → Header assembly → Flange welding → Dimensional inspection → Leak/pressure testing → Surface treatment → Coating → Final inspection
This factory-based manufacturing model allows Radiastar to control critical parameters such as radiator dimensions, welding quality, flange position, surface treatment and pressure-tightness.
For high-voltage power transformer radiator applications, dimensional accuracy and leak-tightness are particularly important.
Radiastar can perform quality control covering:
Each radiator must maintain adequate mechanical integrity and oil-tightness before shipment.
For a 220kV / 120MVA transformer, radiator selection should not be based only on radiator dimensions.
The complete cooling system should be considered together with:
Radiastar works with transformer manufacturers and EPC contractors to customize radiator dimensions and connection configurations according to the transformer design.
Important: The radiator dimensions listed in this case are reference configuration values, not a universal radiator specification for every 120 MVA / 220 kV transformer. Final radiator quantity, heat-dissipation capacity, fan arrangement and dimensions should be confirmed according to the transformer’s thermal calculation and OEM design requirements.
Radiastar provides transformer radiators, corrugated transformer tanks and other transformer tank components for oil-immersed power transformers.
The company can manufacture radiator configurations according to customer drawings or provide engineering recommendations based on transformer capacity, cooling mode, installation requirements and connection dimensions.
For projects involving 220kV transformers, 120MVA power transformers, ONAN/ONAF cooling systems or customized transformer radiators, customers can provide the transformer technical specification or radiator drawing for engineering review.
