Excellence in innovation, the power source, three phase pad mounted transformer sets a new benchmark in the electrical field!
01 General
1.1 Project Description
This 3000 kVA three-phase pad transformers was delivered to Salvador in 2025, designed for urban distribution systems and large-load areas. It’s a powerful unit with ONAN natural oil circulation cooling, built to handle complex load scenarios while staying reliable. The transformer comes packed with safety features and flexible management options, making it a robust solution that keeps energy flowing smoothly, even under demanding conditions. It’s not just a piece of equipment-it’s engineered to balance performance, safety, and operational flexibility in one neat package.
1.2 Technical Specification
3000 kVA pad transformers specifications type and data sheet
| Delivered to | Salvador |
| Year | 2025 |
| Type | Pad mounted transformer |
| Standard | NEMA |
| Rated Power | 3000 kVA |
| Frequency | 60HZ |
| Phase | 3 |
| Feed | Loop |
| Front | Dead |
| Cooling Type | ONAN |
| Primary Voltage | 23D kV |
| Secondary Voltage | 0.38y/0.219 kV |
| Winding Material | Copper |
| Angular displacement | Dyn1 |
| Impedance | 5.75% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 3 kW |
| On Load Loss | 28.7 kW |
| Accessories | Standard Configuration |
1.3 Drawings
3000 kVA pad transformers diagram drawing and size.
1.4 Core Technical Highlights
The transformer features high-quality copper windings, boosting electrical conductivity and reducing energy losses. On the low-voltage side, a 10-hole bushing combined with a sturdy support bracket ensures the windings stay firmly in place, even under mechanical stress or vibration. This thoughtful design improves long-term reliability and stability, keeping connections solid and the transformer running smoothly over years of operation.
Using a three-phase, three-limb core, this transformer maximizes magnetic efficiency while minimizing losses. Each phase has its own vertical limb, which allows magnetic flux to flow seamlessly and reduces acoustic noise and vibration. It’s not just about energy efficiency-the structure also enhances operational dependability and keeps the transformer quiet, steady, and efficient, no matter the load.
Equipped with a four-position load break switch, this transformer can adapt to changing load demands with ease. Its built-in bayonet fuse and ELSP fuse offer additional protection, guarding against overloads and short circuits. The Dyn1 vector group further ensures smooth compatibility with the network while maintaining safe, reliable operation. Together, these features give operators both control and confidence.
The oil tank is made from high-strength low-carbon steel and coated with multiple anti-corrosive layers, built to withstand the test of time. Automated welding ensures airtight sealing and structural stability, while the tank’s dimensions and design are tailored to optimize heat dissipation. Every detail, from the material choice to the coating, is meant to keep the transformer running cool, durable, and trouble-free.
02 Manufacturing
2.1 Core
| Adopting a three-phase, three-limb core design, this transformer delivers remarkable enhancements to magnetic performance and overall operational efficiency. With each phase dedicated to a separate vertical limb, the configuration minimizes core losses substantially while enabling seamless magnetic flux propagation. Beyond elevating energy conversion efficacy and bolstering system dependability, this structural arrangement also mitigates acoustic emissions and mechanical oscillations throughout its operational lifecycle. |  |
2.2 Winding
 | Winding Design: Each phase comprises multiple insulated wire coils, with the turn count adjustable to exact specifications for achieving the desired voltage ratio. Connection layouts include two primary schemes: the star (Y) configuration, where one end of each winding converges at a shared neutral node-making it optimal for systems requiring a neutral connection-and the delta (Δ) arrangement, which links windings in a closed series loop by joining the termination of one phase to the initiation of the next, rendering it highly suitable for high-power scenarios. As for insulation, high-grade materials like polyester film and epoxy resin are integrated to deliver robust electrical separation, preventing short circuits and boosting efficiency by curbing power dissipation. |
2.3 Tank
| Crafted from high-tensile low-carbon steel, the transformer’s oil tank boasts a specially conditioned surface that maximizes coating adherence, while automated welding processes are utilized across the entire assembly to ensure uniform weld quality and airtight sealing reliability. For enhanced long-term durability, its inner walls are coated with a multi-layer anti-corrosive finish, and the tank’s dimensional parameters and structural geometry are tailor-designed to match the transformer’s specific rating requirements-further enabling efficient thermal regulation and optimal heat dispersion. |  |
2.4 Final Assembly
 | After the core and windings undergo precise assembly and installation-with all interconnections validated for correctness-the oil tank is firmly affixed and filled with insulating fluid of the specified grade. Next, electrical terminations for both high-voltage and low-voltage sides are executed in strict compliance with safety protocols, and the process concludes with the integration of essential accessories: temperature sensors, pressure relief valves, and oil level indicators, among others. |
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximun resistance unbalance rate≤5% | 3.16 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: Dyn1 | -0.11%~-0.03% | Pass |
| 3 | phase-relation tests | / | Dyn1 | Dyn1 | Pass |
| 4 | No-load losses and excitation current | / | I0 : provide measured value | 0.32% | Pass |
| P0: provide measured value(t:20℃) | 2.654kW | ||||
| the tolerance for no load loss is +10% | / | ||||
| 5 | Load losses impedance voltage and efficiency | / | t:85℃ the tolerance for impedance is ±7.5% the tolerance for total load loss is +6% | / | Pass |
| Z%: measured value | 6.16% | ||||
| Pk: measured value | 26.535kW | ||||
| Pt: measured value | 29.189 kW | ||||
| Efficiency not less than 99.37% | 99.42% | ||||
| 6 | Applied Voltage Test | kV | HV: 40kV 60s LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | kV | Applied voltage (kV):2Ur | No collapse of the test voltage occurs | Pass |
| Induced voltage(kV): 46 | |||||
| Duration(s):48 | |||||
| Frequency (HZ): 150 | |||||
| 8 | Leakage Test | kPa | Applied pressure：20kPA | No leakage and no Damage | Pass |
| Duration：12h | |||||
| 9 | Insulation Resistance Measurement | GΩ | HV-LV to Ground : | 6.02 | / |
| LV-HV to Ground: | 8.39 | ||||
| HV&LV to Ground: | 4.66 | ||||
| 10 | Oil Dielectric Test | kV | ≥45 | 57.38 | Pass |
04 Packing and Shipping
05 Site And Summary
Our three phase pad transformers are designed to meet the highest standards of performance, reliability, and safety in electrical distribution. Equipped with advanced technology and robust construction, these transformers ensure efficient power management while minimizing environmental impact. Whether for residential, commercial, or industrial applications, our transformers provide a reliable solution for your energy needs. Choose our Three Phase Pad Mounted Transformers for unparalleled quality and service, helping you power the future with confidence.
