Reliable dual primary voltage loop-feed transformers from Scotech ensure stable, high-efficiency power for every application
01 General
1.1 Project Description
Our Canadian partner, with over 30 years of experience in the power industry, has placed strong trust in Scotech. By September 2025, have ordered a total of 66 pad-mounted and pole-mounted transformers from us.
Scotech makes custom solutions for each project. Their latest order is for two 2500 kVA loop-feed three-phase pad-mounted transformers. They are built to the CSA C227.4:21 standard. These transformers can be used in many sectors, including data centers, crypto mining, utilities, renewable energy, industrial, and construction.
This loop feed transformer works with input voltages of 12.47 kV and 24.94 kV. It gives 0.6 kV on the secondary side and has a maximum capacity of 2500 kVA. The dual primary voltage lets it connect to different grids. It is good for utilities, commercial buildings, and industrial sites. The transformer has an ONAN cooling system. It uses high-quality mineral oil and does not contain PCBs. This makes it safe, reliable, and environmentally friendly.
The transformer has a Dyn1 vector group. It has an NLTC tap changer with a tapping range of ±2×2.5%. The loop feed transformer follows the CSA C802.1-13 efficiency standard. Its overall efficiency is 99.37%, which is higher than most transformers of this size. Its no-load loss of 2.5 kW and on-load loss of 24 kW are both relatively low, reflecting optimized core design and high-quality winding materials. The transformer uses less energy, costs less to run, and works well for a long time.
1.2 Technical Specification
2500kVA three phase pad mounted transformer specification and data sheet
| Delivered to | Canada |
| Year | 2025 |
| Type | Three phase pad mount transformer |
| Standard | CSA C227.4:21 |
| Rated Power | 2500kVA |
| Frequency | 60HZ |
| Feed | Loop |
| Front | Dead |
| Phase | three |
| Cooling Type | ONAN |
| Liquid insulant | mineral oil |
| Primary Voltage | 12.47X24.94 kV |
| Secondary Voltage | 0.6 kV |
| Vector Group | Dyn1 |
| Winding Material | Aluminum |
| Impedance | 5.75% |
| Efficiency and Losses Standard | CSA C802.1-13 / 99.37% |
| Tap Changer | NLTC |
| Tapping Range | ±2*2.5% |
| No Load Loss | 2.5 kV |
| On Load Loss | 24 kV |
| Accessories | Standard Configuration |
1.3 Drawings
2500kVA pad mounted transformer diagram and nameplate
02 Manufacturing
2.1 Core
The loop feed transformer core is a critical component in power transformers, serving as the magnetic circuit and facilitating energy transfer between the primary and secondary windings. Our cores are constructed from high-quality silicon steel laminations, designed to minimize energy losses while maximizing magnetic flux density. High-quality transformer cores minimize energy loss as heat. |  |
2.2 Winding
 | With a focus on efficiency and space optimization, the unit utilizes both aluminum winding and copper busbar connections. Most of our three-phase pad-mounted loop feed transformers adopt an optimized coil structure of foil winding for low-voltage coils and wire winding for high-voltage coils, and this unit follows the same design. This design ensures high reliability, stable operation, and improved thermal performance. |
2.3 Tank
All enclosures are constructed from heavy-gauge mild steel and powder coated finish to provide a durable, tamper-resistant surface. Scotech pad-mounted loop feed transformers withstand both tampering and harsh weather, making them safe for installation in public areas. The tank’s exterior is painted Seafoam Green, providing a clean, professional appearance. |  |
2.4 Transformer Electrical Configuration
2.5 Final Assembly
 | 1. Core assembly: The core assembly of the column transformer is assembled on the transformer base or fixed frame according to the design requirements. 2. Winding assembly: Winding wire of a certain specification is wound on the iron core of the transformer according to the design requirements, including primary winding and secondary winding. Use insulation to isolate the winding coils. 3. Insulation treatment: the winding is insulated, including insulating paint treatment and baking, to ensure good insulation performance. 4. Install other components: three resin-cast LV bushings (spade-type, 8 holes), three HV bushings (separable insulated connectors, 200 A), six bayonet fuses, six ELSP fuses, one 2-position load break switch, one de-energized tap changer (±2 × 2.5%), and one dual-voltage selector switch and so on. 5. Insulation oil injection: The insulation oil is injected into the loop feed transformer oil tank to fill the transformer internal space and ensure that the oil level height meets the requirements. |
03 Testing
Testing Standard and Routine Test
CSA C227.4-21 Three-phase, pad-mounted distribution transformers with separable insulated high-voltage connectors
CSA-C802.1-13 (R2018) Minimum Efficiency Values for Liquid-Filled Distribution Transformers
- Resistance Measurements
- Ratio Tests
- Phase-relation Test
- No Load Losses and No Load Current
- Load Losses, Impedance Voltage and Efficiency
- Applied Voltage Test
- Induced Voltage Withstand Test
- Leak Testing with Pressure for Liquid Immersed Transformers
- Insulation Resistance Measurement
- Oil Dielectric Test
Test Results
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | % | Maximum resistance unbalance rate | 1.12 | Pass |
| 2 | Ratio Tests | % | The deviation of voltage ratio on the principal tapping: ±0.5% | 12.47(-0.02~0.03) 24.94(0.08~0.09) | Pass |
| 3 | phase-relation tests | / | Dyn1 | Dyn1 | Pass |
| 4 | No-load losses and excitation current | / | I0 :: provide measured value | 0.26% | Pass |
| P0: provide measured value | 2.393kW | ||||
| 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 | 5.60% | ||||
| Pk: measured value | 21.860kW | ||||
| Pt: measured value | 24.253kW | ||||
| Efficiency not less than 99.37% | 99.42% | ||||
| 6 | Applied Voltage Test | kV | LV: 50kV 60s HV: 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 Duration：24h | No leakage and no Damage | Pass |
| 9 | Insulation Resistance Measurement | GΩ | LV-HV to Ground | 7.28 | / |
| HV-LV to Ground | 18.3 | ||||
| HV&LV to Ground | 6.67 | ||||
| 10 | Oil Test | / | Dielectric Strength; | 58.4 | Pass |
| Moisture Content | 9.5 | ||||
| Dissipation Factor | 0.168 | ||||
| Furan Analysis | 0.03 |
04 Site and Summary
This 2500 kVA three-phase pad-mounted loop feed transformer is strong, efficient, and reliable. It has dual primary voltage, high efficiency of 99.37%, and low losses. The design includes a durable tank, advanced core and coil, and full accessories. It works well in utilities, industry, and commercial sites. It is safe, long-lasting, and friendly to the environment. This project shows that Scotech can provide custom transformer solutions for partners around the world.
