SCOTECH's 300 kVA dead-front transformers offer reliable, CSA-compliant power for Canada.
01 General
1.1 Project Description
In 2024, a Canadian client placed an order for eight 300 KVA dead front transformers designed and manufactured in full compliance with CSA Standard C227.4:21. These transformers are built for reliable operation in outdoor, loop-fed distribution systems with effectively grounded networks.
A 300 kVA three-phase pad-mounted transformer was supplied as part of this project. It has a dead-front design that ensures safety and easy operation. The cooling method is ONAN, providing reliable heat dissipation under all load conditions. The transformer uses mineral oil insulation and aluminum windings, giving a good balance between high efficiency and cost. It is rated at 300 kVA, 60 Hz, with a primary voltage of 12.47 and a secondary voltage of 0.208 kV.
The winding connection is YNyn0, suitable for grounded distribution networks. A no-load tap changer (NLTC) is provided with a ±2×2.5% tapping range. This allows convenient voltage adjustment to match different operating conditions and ensure stable system performance. The transformer achieves 98.94% efficiency, with no-load losses ≤705 W and load losses ≤4000 W. It features standard CSA-compliant accessories and a 5-legged core design for stable performance under a grounded Y–Y connection.
This delivery reflects SCOTECH’s commitment to delivering high-quality, CSA-certified transformers tailored for the Canadian power distribution market.
1.2 Technical Specification
300kVA three phase pad mounted transformer specification and data sheet
| Delivered to | Canada |
| Year | 2024 |
| Type | Three phase pad mount transformer |
| Standard | CSA C227.4:21 |
| Rated Power | 300KVA |
| Frequency | 60HZ |
| Feed | Loop |
| Front | Dead |
| Phase | three |
| Cooling Type | ONAN |
| Liquid insulant | Mineral Oil |
| Primary Voltage | 12.47(4.16) kV |
| Secondary Voltage | 0.208 kV |
| Vector Group | YNyn0 |
| Winding Material | Aluminum |
| Impedance | 4 % |
| Efficiency | 98.94% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | ≤800 W |
| On Load Loss | ≤3580 W |
| Accessories | Standard Configuration |
1.3 Drawings
300kVA three phase pad mounted transformer drawing and nameplate
02 Manufacturing
2.1 Oil Level Indicator
The oil level indicator lets you see the 300 kVA dead front transformers’ oil at a glance, in real time, so you know if it’s where it should be. Oil isn’t just insulation-it carries away heat from windings and the core too. If the level drops, it could be a leak, or something inside might be wrong. With visual cues or sensors, operators can top up or check quickly, helping prevent failures and extend life. Usually installed where it’s easy to check, it makes daily inspections safer and simpler. |  |
2.2 IFD & Drain Valve
 | The Internal Fault Detector, IFD, and the drain valve each have their role, but together they keep the transformer safe. The IFD senses unusual gases or small arc signals, warning about winding or insulation issues early. The drain valve lets you remove oil, for regular maintenance or emergencies. With both, you can catch risks early and handle oil safely. Especially in three-phase transformers, timely alerts and controlled oil handling help keep everything stable and avoid bigger problems down the line. |
2.3 PRV & Vacuum Gauge
Inside the transformer, the pressure relief valve and vacuum pressure gauge act like a little safety team. Relief valve-opens when gas pressure climbs too high; protects tank, seals. Vacuum gauge-shows pressure swings, hints at temperature changes, oil expansion, maybe sealing issues. Together, a quick look gives operators the overall picture. Spot overpressure, negative pressure early; helps save insulation, mechanical parts. Especially important in three-phase transformers, where one fault can ripple through the whole unit. |  |
2.4 Thermometer
 | The thermometer tracks oil and winding temperatures, showing how hot the transformer is running. High heat ages oil faster, stresses insulation, and can overwork windings. Watching the readings helps operators decide whether to reduce load, ventilate more, or plan maintenance. The info can be checked manually or fed into monitoring systems. For three-phase units, it’s crucial to see each phase’s temperature, keeping things balanced, avoiding surprises, and making sure power keeps flowing steadily. |
03 Testing
| Testing Standard | |
| CSA C227.4-21 | Three-phase, pad-mounted distribution transformers with separable insulated high-voltage connectors |
| CSA-C802.1-13 (R2022) | Minimum Efficiency Values for Liquid-Filled Distribution Transformers |
Routine Test
1 Resistance Measurements
2 Ratio Tests
3 Phase Relation Test
4 No Load Losses and No Load Current
5 Load Losses Impedance Voltage and Efficiency
6 Applied Voltage Test
7 Induced Voltage Withstand Test
8 Leak Testing with Pressure for Liquid Immersed Transformers
9 Insulation Resistance Measurement
10 Oil Dielectric Test
04 Packing and Shipping
