100 kVA Residential Transformer by Scotech- Efficient Voltage Conversion for Modern Homes
01 General
1.1 Project Description
This 100kVA single phase residential transformer was delivered to Guyana in 2024. Maintain strict conformity with IEEE & ANSI C57.12.00 standards. The polarity is subtractive, and the vector group is Ii0. Capable of transforming voltage from 13,800V down to 120/240V, this transformer has a kVA rating of 100 for reliable performance. Making it suitable for residential and light commercial applications. Designed with copper windings, this transformer ensures superior conductivity and operational efficiency. The ONAN cooling method ensures effective heat dissipation, promoting long-term reliability.
With a ±2.5% tapping range and a total range of 10%, it features superior transient response in voltage regulation, reducing the impact of load surges for enhanced protection. The Single phase pole mounted transformer’s no-load loss is 263W, and the on-load loss is 897W, ensuring energy-efficient performance. It features an impedance of 2.4%, minimizing voltage drop under load conditions. Scotech specializes in selling polemount transformers to customers in the commercial and industrial space.
1.2 Technical Specification
100kVA pole mounted residential transformer specification and data sheet
| Delivered to | Guyana |
| Year | 2024 |
| Type | Single phase pole mounted transformer |
| Standard | IEEE & ANSI C57.12.00 |
| Rated Power | 100KVA |
| Frequency | 60HZ |
| Polarity | Subtractive |
| Vector group | Ii0 |
| Primary Voltage | 13800V |
| Secondary Voltage | 120/240V |
| Winding Material | COPPER |
| Impedance | 2.4% |
| Cooling Method | ONAN |
| Tap Changer | NLTC |
| Tapping Range | ±2X2.5%(Total range=10%) |
| No Load Loss | 263W |
| On Load Loss | 897W |
| Accessories | Standard Configuration |
1.3 Drawings
100kVA pole mounted residential transformer dimensions and weight details
02 Manufacturing
2.1 Core
| Wound Transformer Cores is a simple and effective design application for silicon steel cores for distribution transformers. Dramatically reduces the time needed to assemble a distribution transformer and no additional clamping or similar hardware is required to complete core construction. Many power distribution companies in the North and South American markets prefer wound iron cores. |  |
2.2 Winding
 | Our transformer windings use high-purity enameled round copper wire, featuring excellent electrical conductivity and compact insulation. Strong adhesion of enamel improves durability and wear resistance. Adopt an optimized coil structure of foil winding for low-voltage coils and wire winding for high-voltage coils, ensuring excellent operational stability, reliability, and thermal performance. |
2.3 Tank
Transformer tank fabrication involves precision engineering and skilled craftsmanship to ensure the tanks’ durability. All welds of the tank must be straight, smooth, and uniform, with no cold joints, weld beads, pores, or bulges, and should be done in a single continuous pass where possible. Welds must be ground flat and free of cracks. Tank covers must not have noticeable water-collecting areas.
2.4 Final Assembly
 | 1. Winding Assembly: Slide the HV/LV windings onto the laminated core, ensuring proper alignment and insulation integrity. 2. Electrical Connections: Connect winding leads to tap changer, bushings, and other components, then secure and insulate the joints. 3. Core-Coil Drying: Place the assembled active part (core + windings) into a drying oven for vacuum heating to remove moisture. 4. Tank Installation: Hoist the dried active part into the tank, position it securely, and ensure proper insulation from the tank walls. 5. Accessory Mounting: Install bushings, pressure relief valve and other accessories, then check for leaks. 6. Oil Filling & Settling: Vacuum-fill with insulating oil, degas, and allow settling before checking oil levels and dielectric strength. |
03 Testing
Routine Test
- Resistance Measurements
- Ratio Tests
- Polarity Test
- No Load Losses and No Load Current
- Load Losses and Impedance Voltage
- Applied Voltage Test
- Induced Voltage Withstand Test
- Insulation Resistance Measurement
- Leak Testing with Pressure for Liquid Immersed Transformers
- Oil Dielectric Test
Test Results
| No. | Test Item | Unit | Acceptance Values | Measured Values | Conclusion |
| 1 | Resistance Measurements | / | / | / | Pass |
| 2 | Ratio Tests | / | The deviation of voltage ratio on the principal tapping: ≤0.5% Connection symbol: Ii0 | -0.03 | Pass
|
| 3 | Polarity tests | / | Subtractive | Subtractive | Pass
|
| 4 | No-load losses and excitation current | % kW | I0 :: provide measured value P0: provide measured value the tolerance for no load loss is +10% | 0.88 0.211 | Pass
|
| 5 | Load losses , impedance voltage,total losses and efficiency | / kW kW | t:85℃ Z%: measured value Pk: measured value Pt: measured value the tolerance for impedance is ±10% the tolerance for total load loss is +6% | 2.29 0.823 1.034 99.21 | Pass
|
| 6 | Applied Voltage Test | / | HV：34KV 60s LV: 10kV 60s | No collapse of the test voltage occurs | Pass
|
| 7 | Induced Voltage Withstand Test | / | Applied voltage (KV): 2 Ur Duration(s): 48 Frequency (HZ): 150 | No collapse of the test voltage occurs | Pass
|
| 8 | Insulation Resistance Measurement | GΩ | HV-LV to Ground LV-HV to Ground HV&LV to Ground | 66.7 59.4 60.5 | / |
| 9 | Leakage Test | / | Applied pressure：20kPA Duration：12h | No leakage and no Damage | Pass
|
| 10 | Oil Dielectric Test | kV | ≥45 | 52.33 | Pass
|
04 Packing and Shipping
05 Site and Summary
This 100kVA single-phase pole-mounted transformer is designed for reliable residential and light commercial power distribution. With efficient copper windings, durable construction, and strict quality control, it delivers stable performance and long-term service in demanding environments.
