Reliable Power, Compact Design – Pad Mounted Transformers for a Smarter Grid!
01 General
1.1 Project Description
750 kVA three phase pad mounted transformer was delivered to Canada in 2025. The rated power of the transformer is 750 kVA with ONAN cooling. The primary voltage is 25D kV with ±2*2.5% tapping range (NLTC), the secondary voltage is 0.6y/0.347 kV, they formed a vector group of Dyn1.
CSA-certified pad-mounted transformers meet the rigorous standards set by the Canadian Standards Association (CSA) for electrical performance, durability, and environmental resilience. Pad-mounted transformers are robust, compact, and highly efficient electrical distribution units designed for outdoor installation at ground level. Encased in durable, tamper-resistant enclosures, these transformers provide safe and reliable power conversion for urban, suburban, and industrial applications. Their space-saving design minimizes footprint while ensuring easy access for maintenance.
With advanced insulation, corrosion resistance, and weatherproof construction, pad-mounted transformers deliver consistent performance in diverse environments-from smart grids and renewable energy systems to commercial complexes and utility networks. Engineered for safety, efficiency, and longevity, they are the trusted choice for modern power distribution.
1.2 Technical Specification
1500 kVA pad mounted transformer specifications type and data sheet
| Delivered to | Jamaica |
| Year | 2025 |
| Type | Pad mounted transformer |
| Standard | CSA 2.1-06 |
| Rated Power | 750 kVA |
| Frequency | 60HZ |
| Phase | 3 |
| Feed | Loop |
| Front | Dead |
| Cooling Type | ONAN |
| Primary Voltage | 25D kV |
| Secondary Voltage | 0.6Y/0.347 kV |
| Winding Material | Aluminum |
| Angular displacement | Dyn1 |
| Impedance | 4.75% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 1.4 kW |
| On Load Loss | 8.03 kW |
| Accessories | Standard Configuration |
1.3 Drawings
750 kVA pad mounted transformer diagram drawing and size.
02 Manufacturing
2.1 Core
| This 750kVA pad-mounted transformer utilizes high-grade CRGO core laminations in a precision three-phase, three-limb configuration. The step-lap stacked laminations feature 45° mitred joints and epoxy bonding to minimize losses and ensure structural stability. This optimized lamination design delivers superior efficiency, meeting CSA standards, with optional amorphous metal cores for ultra-high efficiency applications. The robust construction guarantees reliable performance in demanding utility environments. |  |
2.2 Winding
 | This 3 winding transformer features precision-engineered HV/LV windings using aluminum conductors with insulating material. The HV winding employs layer-wound design, while LV uses foil/helical construction for high current capacity. The 3 winding configuration enables flexible voltage transformation. Axial/radial bracing withstands short-circuit forces. |
2.3 Tank
| This eco-friendly tank transformer features a corrosion-resistant, powder-coated steel enclosure with lead-free paint, offering superior UV protection and environmental safety. The 100% leak-proof green tank design prevents soil contamination while supporting biodegradable FR3 fluid. Engineered for sustainability and performance, it delivers quiet operation (<65dB) and includes reinforced lifting points with optional seismic bracing. |  |
2.4 Final Assembly
 | 1. Winding Assembly & Core Stacking Slide HV/LV windings onto the core legs, ensuring proper insulation placement. Insert yoke laminations and clamp the core to form a complete magnetic circuit. 2. Electrical Connections Connect leads via welding or bolting, wire tap changers, bushings, and other terminals; verify clearances. 3. Active Part Drying Transfer the active part (core + windings) into an oven for vacuum-hot-air drying until moisture content meets standards. 4. Tank Installation Hoist the dried active part into the tank, align, and secure with clamping bolts; seal the tank cover. 5. Accessory Mounting Install accessories such as bushings, pressure relief devices, oil gauges, bayonet fuse, and control wiring. 6. Oil Filling & Sealing Vacuum-fill with insulating oil to the specified level. After settling, test oil dielectric strength and moisture content; perform final leak checks. |
03 Testing
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximum resistance unbalance rate | 0.81 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ≤0.5% | 0.00 | Pass |
| 3 | phase-relation tests | / | Dyn1 | Dyn1 | Pass |
| 4 | No-load losses and excitation current | / | I0 :: provide measured value | 0.53% | Pass |
| P0: provide measured value | 1.197kW | ||||
| 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 | 4.55% | ||||
| Pk: measured value | 7.325kW | ||||
| Pt: measured value | 8.522kW | ||||
| Efficiency not less than 99.15% | 99.25% | ||||
| 6 | Applied Voltage Test | kV | HV:50kV 60s LV: 10kV 60s | No collapse of the test voltage occurs | Pass |
| 7 | Induced Voltage Withstand Test | kV | Applied voltage (KV): 2 Ur | No collapse of the test voltage occurs | Pass |
| Duration(s):48 | |||||
| Frequency (HZ): 150 | |||||
| 8 | Leakage Test | kPa | Applied pressure：20kPA Duration：12h | No leakage and no Damage | Pass
|
| 9 | Insulation Resistance Measurement | GΩ | HV-LV to Ground | 10.6 | / |
| LV-HV to Ground | 10.4 | ||||
| HV&LV to Ground | 9.12 | ||||
| 10 | Oil Test | / | Dielectric Strength; | 57.3 kV | Pass |
| Moisture Content | 9.9 mg/kg | ||||
| Dissipation Factor | 0.00247% | ||||
| Furan Analysis | 0.03 | ||||
| Gas Chromatography Analysis | / |
04 Packing and Shipping
4.1 Packing
| The pad-mounted transformer package utilizes a robust wooden crate reinforced with steel straps, featuring forklift slots or lifting points for handling. The unit secured to wooden skids inside the crate, and cushioned with foam or rubber padding to absorb shocks. Accessories are packed separately in layered compartments. The exterior is covered with waterproof plastic sheeting and includes desiccant bags, while labels indicate the center of gravity, moisture protection, “Do Not Tilt,” and technical specifications. This transformer package design ensures shockproof, moisture-resistant, and long-term outdoor protection, delivered in a fully sealed condition for easy on-site inspection and installation. |  |
4.2 Shipping
 | The Pad-Mounted Transformer will be shipped under CIF terms to the Port of Vancouver, Canada. The seller arranges transportation and basic insurance, providing ISPM 15-compliant fumigated wooden crates (steel-strapped with shock-absorbing padding) and handling export clearance documents (commercial invoice, packing list, certificate of origin, etc.). Shipping uses 40ft open-top containers or flat racks, with the transformer base welded and lashed for securement, plus temperature monitoring throughout transit. Insurance covers. Vancouver Port requires advance declaration of transformer oil type (complying with Canadian EPA regulations), CSA certification (if applicable), and tide window scheduling for unloading. Documents must include the Bill of Lading (with Canada Customs CCN) and insulating oil MSDS report. |
05 Site And Summary
As a cornerstone of power distribution systems, this Pad-Mounted Transformer delivers reliable, efficient, and eco-friendly energy conversion for industrial, commercial, and public infrastructure. Crafted with premium cold-rolled silicon steel and a fully sealed construction, it ensures low-loss, quiet operation while meeting IP67 protection and stringent global standards. The compact tank design optimizes space, and integrated smart monitoring interfaces enable remote management. Certified by CSA/UL for North American compliance, it guarantees durable performance in extreme climates and high-load scenarios-making it the optimal choice for modern grid infrastructure.
