75 kVA powerline transformer solutions-trusted for stable distribution in hard-to-reach areas
01 General
1.1 Project Description
In response to the growing energy demands in rural and peri-urban areas of Guyana, our customer placed a 2025 follow-up order for 30 units of 75 kVA single-phase pole-mounted transformers. This order builds upon their previous procurement of 50 kVA models and reflects their need for higher-capacity equipment to support residential expansion, agricultural development, and rural electrification projects. The continued collaboration underscores the trust placed in our products to deliver stable and efficient power distribution solutions.
These 75 kVA powerline transformers are built to IEEE & ANSI C57.12.00 standards, featuring a primary voltage of 13,800 V and a dual secondary of 120/240 V, with copper windings, 2% impedance, and a ±2×2.5% no-load tap changer for voltage adjustment flexibility. Operating at 60 Hz with ONAN cooling, they are ideally suited for mounting on distribution poles in regions with expanding infrastructure and limited access to centralized substations.
1.2 Technical Specification
75kVA powerline transformer specification and data sheet
| Delivered to | Guyana |
| Year | 2025 |
| Type | Single phase pole mounted transformer |
| Standard | IEEE & ANSI C57.12.00 |
| Rated Power | 50KVA |
| Frequency | 60HZ |
| Polarity | Subtractive |
| Vector group | Ii0 |
| Primary Voltage | 13800V |
| Secondary Voltage | 120/240V |
| Winding Material | COPPER |
| Impedance | 2% |
| Cooling Method | ONAN |
| Tap Changer | NLTC |
| Tapping Range | ±2X2.5%(Total range=10%) |
| No Load Loss | 214W |
| On Load Loss | 713W |
| Accessories | Standard Configuration |
1.3 Drawings
75kVA powerline transformer dimensions and weight details
02 Manufacturing
2.1 Core
| To enhance energy efficiency and operational reliability, this series adopts energy-saving wound cores known for low loss, low noise, and durability. The core surface is coated for anti-moisture and anti-corrosion protection, ensuring stable performance in outdoor environments. |  |
2.2 Winding
 | The HV winding adopts copper foil technology to reduce partial discharge and improve heat dissipation. The LV winding is made of stranded copper wire with tight layering to boost mechanical strength. Our coil designs prioritize insulation clearance and thermal performance for long-term outdoor reliability. |
2.3 Tank
| The tank features a sealed design that has passed rigorous leak testing to ensure excellent sealing, effectively preventing oil leaks and moisture ingress. Made from mild steel with an epoxy paint coating, it offers enhanced corrosion resistance. Equipped with corrugated radiators on both sides, the tank improves heat dissipation efficiency, ensuring stable transformer operation. |  |
2.4 Final Assembly
 | Final assembly begins with placing the wound core and coils into the sealed tank and filling it with insulating oil. External components—including bushings, pressure relief valve, tap changer, grounding parts, and cooling fins—are mounted. The unit is cleaned, painted surface checked, and markings, terminals, and nameplate data thoroughly inspected. |
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
- Oil Dielectric Test
- Leak Testing with Pressure for Liquid Immersed Transformer
Testing Standard
- IEEE C57.12.20-2017
IEEE Standard for Overhead-Type Distribution Transformers 500 kVA and Smaller; High Voltage, 34500 V and Below; Low Voltage, 7970/13 800Y V and Below - IEEE C57.12.90-2021
IEEE Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers - CSA C802.1-13 (R2022)
Minimum Efficiency Values for Liquid-Filled Distribution Transformers
Test results of one pole-mounted transformer from the 30-unit batch
| 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 | -0.06 | 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% | 1.66 0.185 | 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% | 2.08 0.714 0.899 99.08 | 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): 40（50HZ）/48（60HZ） 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 | 101.7 36.1 42.0 | Pass |
| 9 | Leakage Test | / | Applied pressure：20kPA Duration：12h | No leakage and no Damage | Pass |
| 10 | Oil Dielectric Test | kV | ≥45 | 56.71 | Pass |
04 Packing and Shipping
05 Site And Summary
This 75 kVA powerline transformer is designed to meet the growing power demands in rural and peri-urban areas of Guyana. It is well-suited for expanding distribution infrastructure, rural electrification, and agricultural development. The customer’s repeat order in 2025 reflects strong confidence in the stability and performance of our products.
Compliant with North American standards, this transformer series offers high energy efficiency and strong environmental adaptability, making it ideal for installation on distribution poles in low-density regions. The core features a low-loss, energy-saving design for improved operational reliability, while the coil structure is optimized for insulation and heat dissipation, ensuring stable performance in humid outdoor conditions. The sealed tank offers excellent leak prevention and corrosion resistance, and is equipped with radiators to enhance cooling.
With a design focused on long-term stability and minimal maintenance, this powerline transformer is ideal for areas with limited grid coverage and centralized power access, supporting decentralized supply and infrastructure development in rural and developing regions.
