Durable, quiet, efficient – single phase pad mounted transformer you can trust.
01 General
1.1 Project Description
225 kVA single phase transformer pad was delivered to Australia in 2025. The rated power of the single phase transformer pad is 225 kVA with ONAN cooling. The high voltage is 8.32GrdY/4.8 kV with ±2*2.5% tapping range (NLTC), the low voltage is 0.24/0.12 kV, they formed a vector group of Ii6.
The unit is ideal for supplying single‑phase loads such as housing developments, street lighting, small commercial centers, and rural electrification projects where space is limited and appearance matters. Typical installations include utility‑owned or private pad‑mount systems in suburban neighborhoods, industrial parks, and renewable energy sites (e.g., solar farm auxiliary power). The transformer fully complies with CSA C227.3 and CSA C802.1 latest editions, making it suitable for Canadian and North American standards‑driven markets. Its outdoor enclosure and loop feed configuration allow seamless integration into underground loop circuits, enhancing service continuity.
Key Design Highlights
- High efficiency & low losses – Minimum efficiency 99.06%; impedance 4% (±7.5%). No‑load loss ≤10% and total loss ≤6% to avoid penalties.
- Safe operation – Dead‑front, loop feed construction with additive polarity. Includes Kirk key interlock to enforce proper switching sequence, preventing accidental entry into live parts and significantly enhancing operational safety.
- Complete protection & control – 4‑position load break switch, off‑circuit tap changer ±2×2.5%, bayonet fuse, CLF, pressure relief device, oil level gauge, top oil temperature gauge, and vacuum pressure gauge.
- Durable outdoor design – Mild steel tank finished in Green Munsell 9GY1.5/2.6; ONAN cooling, mineral oil, aluminum windings.
1.2 Technical Specification
225 kVA single phase transformer pad specifications type and data sheet
| Delivered to | Canada |
| Year | 2025 |
| Type | Pad mounted transformer |
| Standard | CSA C227.3 |
| Rated Power | 225 kVA |
| Frequency | 60HZ |
| Phase | 3 |
| Feed | Loop |
| Front | Dead |
| Cooling Type | ONAN |
| Primary Voltage | 8.32GrdY/4.8 kV |
| Secondary Voltage | 0.24/0.12 kV |
| Winding Material | Aluminum |
| Vector Group | Ii6 |
| Impedance | 4% |
| Efficiency | 99.06% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | ≤0.32 kW |
| On Load Loss | ≤3.63 kW |
| Color | Musell 9GY1.5/2.6 |
1.3 Drawings
02 Manufacturing
2.1 Core
| The core is made of high-permeability grain-oriented silicon steel, with an optimized stacked design to minimize hysteresis and eddy current losses. Under 105% rated voltage, the core maintains low flux density, ensuring excellent excitation performance. Measured no-load loss: 248 W Measured no-load current: 0.12% |  |
2.2 Winding
 | Both HV and LV windings are aluminum, fully complying with customer requirements. Resistance values are well balanced across all taps. Test results show HV resistance ranges from 0.4058 Ω to 0.4474 Ω, and LV resistance from 0.7248 mΩ to 1.5990 mΩ, confirming stable operation under rated load. |
2.3 Tank
| The tank is constructed from mild steel and finished in Munsell 9GY1.5/2.6 green as specified. Designed for outdoor installation, it is equipped with an oil level gauge, pressure relief device, vacuum pressure gauge, and drain/fill valves. The tank passed a 20 kPa / 12 hours leakage test – no leakage, no permanent deformation, ensuring excellent sealing and weather resistance. |  |
2.4 Final Assembly
 | The single phase transformer pad is configured as a fully integrated single-phase pad-mounted unit for dead-front, loop-feed operation. All high-voltage components (load break switch, tap changer, fuses) are housed inside the sealed tank with interlocked access. A Kirk Key system ensures the load break switch must be opened before the fuse compartment can be accessed. The LV compartment features 4-hole spade terminals (240/120V) with integral grounding. Monitoring devices (oil temperature, oil level, pressure) are mounted on a centralized panel. The unit sits on a rugged steel base with parking stands for easy site installation. This compact design enhances safety, reduces installation time, and ensures reliable operation. |
03 Testing
All routine tests have been successfully completed. Key results:
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | / | / | / | Pass |
| 2 | Ratio Tests | / | The deviation of voltage ratio on the principal tapping: ≤±0.5% Connection symbol: Ii6 | A: +0.07 B: +0.07 | Pass |
| 3 | Polarity tests | / | Additive | Additive | Pass |
| 4 | No-load losses and excitation current | % kW | I0 :: provide measured value P0: provide measured value the tolerance for no load loss is +0% | 0.12 0.248 | Pass |
| 5 | Load losses and impedance voltage | % kW kW % | t:85℃ Z%: measured value Pk: measured value Pt: measured value the tolerance for impedance is ±7.5% the tolerance for total load loss is +0% | 4.24 3.027 3.275 99.18 | Pass |
| 6 | Applied Voltage Test | / | LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | / | Applied voltage (KV): 0.88 Duration(s):30 Frequency (HZ): 240 | No collapse of the test voltage occurs | Pass |
| 8 | Insulation Resistance Measurement | GΩ | LV-HV to Ground | 11.6 | / |
| 9 | Leakage Test | / | Applied pressure：20kPA Duration：12h | No leakage and no Damage | Pass |
| 10 | Oil Dielectric Test | kV | ≥45 | 59.5 | Pass |
04 Packing and Shipping
4.1 Packing
The transformer is packed with anti-moisture, anti-vibration, and anti-rust protection, suitable for sea or land transport. The tank is securely fixed, and accessories are individually packed with a detailed packing list.
4.2 Shipping
Each shipment includes:
- English test report
- Certificate of conformity
- Operation manual (including manual operation instructions)
- Paint sample approval confirmation
- Available on CIF terms, with full export documentation.
05 Site And Summary
| Aspect | Status |
| Parameter matching | Fully matches customer specifications (voltage, capacity, impedance, losses, color, accessories, etc.) |
| Standard compliance | Complies with CSA C227.3, CSA C802.1, CSA C2.2-06 |
| Reliability (testing) | All routine tests passed – including dielectric, insulation, sealing, loss, and impedance tests |
| Quality assurance | Manufactured under ISO9001: raw material control, in-process inspections, full traceability |
