A transformer assembly factory in Nigeria ordered 2 units sample 800 kVA corrugated transformer tank for its oil-immersed distribution transformer production.
The tank was designed for a 3-phase, 11/0.4 kV, 800 kVA oil-immersed transformer with ONAN cooling. Instead of purchasing a complete transformer, the customer sourced the corrugated tank separately and planned to complete the core, winding, electrical accessories and final assembly locally.
For this type of OEM project, the customer was particularly concerned about tank dimensions, steel construction, corrugated fin specifications, welding quality, oil tightness, surface treatment and dimensional accuracy.
The sample was therefore produced according to the customer’s transformer design and approved mechanical requirements before subsequent batch production.
| Item | Specification |
|---|---|
| Project Location | Nigeria |
| Customer | Transformer Assembly Factory |
| Product | Corrugated Transformer Tank |
| Transformer Capacity | 800 kVA |
| Voltage Rating | 11/0.4 kV |
| Phase | 3 Phase |
| Cooling Method | ONAN |
| Tank Type | Corrugated Oil-Immersed Transformer Tank |
| Application | Distribution Transformer |
| Tank Material | Weldable Carbon Steel |
| Fin Strip Thickness | 1.2 mm |
| Fin Depth | 300 mm |
| Fin Distance | 45 mm |
| Panel Height | 1,200 mm |
| Welding | Qualified Welding Process |
| Oil Tightness | Leakage / Tightness Tested |
| Surface Treatment | Anti-Corrosion Coating |
| Supply Scope | Tank Sample |
| Manufacturing | OEM / Customized |
| Standard Basis | IEC 60076 Series |
Note: The dimensions shown above are a representative configuration for this project. Final tank dimensions, steel thickness, corrugation dimensions and oil volume should be confirmed against the customer’s approved GA drawing and transformer design.
The Nigerian transformer manufacturer needed a reliable supplier for a 800 kVA corrugated transformer tank that could be integrated into its existing transformer assembly process.
The customer required:
The customer chose a sample-first procurement approach to verify the tank before proceeding with larger quantities.
The tank was designed as a corrugated oil-immersed transformer tank.
Unlike a conventional flat-wall tank, the side walls are manufactured with multiple formed steel fins.
These corrugations provide:
The basic heat-transfer path is:
Transformer Core & Windings → Insulating Oil → Corrugated Steel Wall → Ambient Air
For an ONAN transformer, the insulating oil circulates naturally as the temperature changes, transferring heat from the active part to the corrugated tank wall.
| Parameter | Specification |
|---|---|
| Transformer Rating | 800 kVA |
| Voltage | 11/0.4 kV |
| Phase | 3 Phase |
| Cooling | ONAN |
| Frequency | 50 Hz |
| Transformer Type | Oil-Immersed |
| Tank Type | Corrugated Tank |
| Panel Height (B) | 1,200 mm |
| Fin Strip Thickness (S) | 1.2 mm |
| Fin Depth (H) | 300 mm |
| Fin Distance (P) | 45 mm |
| Tank Material | Weldable Carbon Steel |
| Tank Plate Thickness | According to Approved Design |
| Corrugated Fin Material | Steel |
| Oil Volume | According to Transformer Design |
| Tank Cover | Customized |
| Lifting Lugs | Customized |
| Earthing Point | Provided |
| Valve Connections | Customized |
| Welding | Qualified Welding Process |
| Oil Tightness | Leakage / Tightness Test |
| Surface Treatment | Anti-Corrosion Coating |
| Final Inspection | Dimensional + Visual + Tightness |
| Standard Basis | IEC 60076 Series |
The corrugated fin is one of the most important components of this transformer tank.
For the 800 kVA sample, the representative configuration was:
The panel height determines the effective cooling surface and contributes to the overall tank dimensions.
A 1.2 mm steel strip provides a balance between forming performance, mechanical strength and manufacturing cost.
The 300 mm fin depth provides sufficient corrugation space for the designed tank structure and contributes to the effective heat-transfer surface.
A 45 mm standard fin distance provides a regular corrugation arrangement and facilitates consistent forming and welding.
The final fin configuration should always be confirmed against the customer’s thermal and mechanical calculations.
The tank body is manufactured from weldable carbon steel plate.
For OEM transformer tanks, material selection should consider:
The exact steel grade and plate thickness can be specified according to the customer’s technical specification.
The tank structure includes:
The final structure is manufactured according to the approved production drawing.
For an oil-immersed transformer tank, welding quality is directly related to oil-tightness.
The manufacturing process focuses on:
Plate preparation → Corrugation forming → Positioning → Welding → Inspection → Tightness Testing
Critical areas include:
The objective is to achieve a mechanically stable and oil-tight tank suitable for transformer assembly.
Oil leakage is one of the most important quality risks during transformer tank procurement.
A leakage problem discovered after the active part has been installed can result in additional assembly and repair costs.
Therefore, the sample tank is inspected for:
The exact test pressure, test duration and testing method should be agreed with the customer according to the approved design and applicable technical requirements.
Because the customer is a transformer assembly factory, dimensional compatibility is critical.
The following dimensions can be checked before shipment:
| Inspection Item | Purpose |
|---|---|
| Overall Tank Length | Assembly compatibility |
| Overall Tank Width | Installation compatibility |
| Tank Height | Transformer active-part clearance |
| Panel Height | Cooling surface verification |
| Fin Depth | Corrugation verification |
| Fin Distance | Forming accuracy |
| Cover Dimensions | Cover matching |
| Lifting Lug Position | Transportation |
| Valve Position | Accessory installation |
| Earthing Position | Grounding connection |
| Mounting Interfaces | Final assembly |
The inspection results can be documented in a final dimensional inspection report.
The tank surface requires suitable anti-corrosion protection, particularly for outdoor transformer applications.
A typical coating process includes:
Surface Preparation
→
Cleaning
→
Primer
→
Intermediate Coating
→
Topcoat
The final coating specification can be customized according to the customer’s requirements and installation environment.
For Nigerian projects, the coating system should be selected according to the actual operating environment, humidity and exposure conditions.
Before shipment, the 1600 kVA corrugated transformer tank can undergo several quality-control procedures.
The finished tank is inspected according to the agreed leakage/tightness testing procedure.
For a transformer assembly factory, approving the tank before mass production can significantly reduce procurement risk.
The Nigerian customer used the sample to verify:
Whether the tank dimensions matched its transformer core and winding assembly.
Whether the fin height, depth, thickness and spacing met the customer’s design requirements.
Whether the tank achieved the required structural integrity and oil tightness.
Whether covers, valves, lifting points and earthing connections matched the customer’s production process.
After sample approval, the approved tank and drawings can be used as the reference for subsequent production.
For buyers sourcing transformer tanks from overseas manufacturers, the following points should be confirmed before production:
The Nigerian transformer assembly factory received a customized 800 kVA corrugated transformer tank sample designed for its 11/0.4 kV, 3-phase ONAN oil-immersed transformer.
The sample incorporated:
1,200 mm panel height
1.2 mm fin strip thickness
300 mm fin depth
45 mm fin distance
Welded steel construction
Oil-tight structure
Anti-corrosion coating
Dimensional and tightness inspection
The sample provided the customer with a practical basis for evaluating mechanical compatibility, manufacturing quality and assembly performance before moving to batch production.
It is a steel enclosure for a 1600 kVA oil-immersed transformer. Corrugated tank walls provide both oil expansion capability and heat dissipation for natural cooling.
This project uses an 11/0.4 kV configuration, with the final voltage specification subject to the customer’s approved transformer design.
The transformer uses ONAN — Oil Natural Air Natural cooling.
The representative configuration uses a 1,200 mm panel height, 1.2 mm fin thickness, 300 mm fin depth and 45 mm fin distance.
Yes. Tank dimensions, steel thickness, corrugation parameters, cover configuration, valve positions, lifting points and other interfaces can be customized according to the customer’s GA drawing.
Typical quality control includes material inspection, dimensional inspection, welding inspection, visual inspection, coating inspection and leakage/tightness testing.
Yes. Corrugated transformer tanks can be manufactured according to the customer’s transformer design, voltage rating, mechanical dimensions and assembly requirements.
