Unseen Power, Unmatched Safety: Our Pad-Mounted Transformer Solution.
01 General
1.1 Project Description
2500 kVA three phase pad mounted transformer was delivered to Canada in 2025. The rated power of the transformer is 2500 kVA with KNAN cooling. The high voltage is 13.8GRDY/7.97 kV with ±2*2.5% tapping range (NLTC), the low voltage is 0.6Y/0.346 kV, they formed a vector group of YNyn0.
We are proud to introduce this 2500kVA pad-mounted transformer, which combines high efficiency, reliability, and environmental sustainability, making it suitable for urban power distribution, commercial, and industrial applications. The product complies with the DOE 2016 energy efficiency standards, achieving an impressive efficiency of up to 99.53%. It utilizes environmentally friendly FR3® natural ester insulating oil, offering high fire safety (K4 class) and biodegradability. Its excellent thermal performance and temperature rise control ensure long-term stable operation.
On the high-voltage side, it features a 600A integrated plug-in bushing, equipped with a neutral porcelain bushing and integrated two-hole spade-type copper bars, providing secure and reliable connections. The low-voltage side is equipped with resin-cast bushings and ten-hole high-current copper bars, ensuring robust construction and easy installation. The innovative side-outlet design saves space and comes complete with full sets of connection copper bars and protective covers, ensuring operational safety. Additionally, two grounding bushings are included for the grounding screen between high and low voltage and for neutral point grounding, offering comprehensive design to meet various grounding requirements.
The enclosure integrates three two-position load break switches, three surge arresters, a grounding shield system, and a nitrogen barrier system, delivering complete protection and flexible operation. This unit is an ideal choice for modern power grid construction, offering high efficiency, safety, and reliability.
1.2 Technical Specification
2500 kVA pad mounted transformer specifications type and data sheet
| Delivered to | USA |
| Year | 2025 |
| Type | Pad mounted transformer |
| Standard | IEEE C57.12.34 |
| Rated Power | 2500 kVA |
| Frequency | 60HZ |
| Phase | 3 |
| Feed | Loop |
| Front | Dead |
| Cooling Type | KNAN |
| Primary Voltage | 13.8GRDY/7.97 kV |
| Secondary Voltage | 0.6Y/0.346 kV |
| Winding Material | Aluminum |
| Angular displacement | YNyn0 |
| Impedance | 5.75% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 2.4 kW |
| On Load Loss | 15.79 kW |
1.3 Drawings
2500 kVA pad mounted transformer diagram drawing and size.
02 Manufacturing
2.1 Core
| This 2500kVA pad-mounted transformer features a three-phase five-limb core constructed from high-quality cold-rolled grain-oriented silicon steel laminations. The five-limb design effectively reduces core reluctance and no-load losses, while significantly minimizing magnetic flux leakage and harmonic content in the core. The two additional side limbs serve as a low-impedance path for third-harmonic flux, thereby suppressing voltage waveform distortion and ensuring high-quality power output. The core exhibits excellent magnetic symmetry and mechanical stability, capable of withstanding short-circuit impacts and reducing operational noise. This robust design provides a solid foundation for the transformer’s highly efficient, smooth, and low-loss operation. |  |
2.2 Winding
 | The low – voltage winding adopts the foil winding process, and the foil has good electrical conductivity, which can improve the current transmission efficiency; the high – voltage winding has a wire – wound structure, which can meet the requirements of high – voltage electricity transmission. The upper and lower parts of the winding are fixed and compressed by steel plates. With the rigidity of the steel plates, the winding is ensured to maintain a stable shape and structure during subsequent processing and use. After forming, the steel plates can be removed, so that the winding meets the overall assembly requirements of the transformer and ensures the electrical performance and mechanical stability of the transformer. |
2.3 Tank
| The tank is constructed from corrosion-resistant steel and features a fully sealed, low-profile design. Finished in Equipment Green (Munsell 9 GY 1.5/2.6), it provides durability and corrosion protection. Filled with FR3® natural ester fluid for enhanced cooling and fire safety, the tank undergoes rigorous leak-proof testing to ensure long-term reliability in demanding environments. |  |
2.4 Final Assembly
 | The final assembly of this pad-mounted transformer begins with the assembly of the active part: the windings are precisely mounted onto the core columns, followed by the insertion of the top yoke laminations to complete the magnetic circuit. All auxiliary components, including bushings, tap changers, and protection devices, are then installed and securely connected. Finally, the tank is carefully filled with FR3® natural ester insulating fluid under controlled vacuum conditions to ensure thorough impregnation and elimination of air, guaranteeing optimal electrical insulation and thermal performance throughout its service life. |
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximun resistance unbalance rate | 4.05 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: YNyn0 | -0.03% ~- 0.02% | Pass |
| 3 | phase-relation tests | / | YNyn0 | YNyn0 | Pass |
| 4 | No-load losses and excitation current | / | I0 :: provide measured value | 0.22% | Pass |
| P0: provide measured value（t:20℃） | 2.192kW | ||||
| 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 合格 |
| Z%: measured value | 5.70% | ||||
| Pk: measured value | 15.158kW | ||||
| Pt: measured value | 17.350 kW | ||||
| Efficiency not less than 99.53% | 99.55% | ||||
| 6 | Applied Voltage Test | kV | LV/低压: 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 |
| Duration(s):48 | |||||
| Frequency (HZ): 150 | |||||
| 8 | Leakage Test | kPa | Applied pressure：50kPA | No leakage and no Damage | Pass |
| Duration：24h | |||||
| 9 | Insulation Resistance Measurement | GΩ | HV-LV to Ground : | 1.22 | / |
| LV-HV to Ground: | 1.45 | ||||
| HV&LV to Ground | 0.758 | ||||
| 10 | Lightning impulse test | kV | full wave | No collapse of the test voltage occurs | Pass |
04 Packing and Shipping
4.1 Packing
This 2500kVA pad-mounted transformer is securely packaged in a custom-built wooden crate, ensuring full protection during transportation and storage. The entire assembly is enclosed within a robust timber enclosure lined with moisture-resistant barriers and cushioning materials to prevent exposure to humidity and physical impacts. Critical components such as bushings and gauges are covered with dedicated protective shields. Internal bracing and tying structures are applied to prevent shifting. The packaging complies with international shipping standards and features clear external markings and handling instructions for safe delivery and easy on-site identification and installation. |  |
4.2 Shipping
 | The transformer will be transported under DDU (Delivered Duty Unpaid) terms to the destination. The supplier handles all transportation arrangements and costs to the specified address, including export procedures and sea/land freight, while the buyer is responsible for import clearance, duties, taxes, and final unloading at the destination. Throughout transit, the shipment will be monitored to ensure mechanical and environmental protection, and upon arrival, the recipient will verify the integrity of the packaging and equipment. |
05 Site And Summary
This transformer combines superior energy efficiency, environmental sustainability, and outstanding reliability to meet the demanding requirements of modern power distribution networks. With exceptional fire safety performance and extended service life, it ensures continuous and stable power supply while reducing operating and maintenance costs. The humanized structural design and fully integrated protection system enhance ease of installation and minimize environmental impact. We are committed to delivering trusted solutions for a wide range of distribution scenarios through advanced technology and rigorous manufacturing, contributing to smarter and more resilient electrical infrastructure.
