Recently, GNEE Electric completed production and official shipment of 2 sets of 1600 kVA oil-immersed distribution transformers for a prefabricated concrete transformer substation (BTS) project in Bulgaria. The equipment will be deployed in a grid-connected photovoltaic (PV) + battery energy storage system (BESS) hybrid station, supporting local renewable energy grid integration and stable low-voltage power distribution.
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Client Profile
Our client is a well-established local EPC contractor headquartered in Bulgaria, specializing in the design, EPC construction and grid connection of distributed PV stations and utility-scale BESS facilities. With rich project experience across the Balkan region, the client implements full-process management in strict accordance with IEC international standards and EU grid access requirements.
This 1600 kVA transformer supply serves a medium-sized PV+BESS integrated station equipped with prefabricated compact substations.
GNEE Electric Targeted Solution
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Aiming at the above pain points, our technical team provided a fully customized 1600 kVA oil-immersed transformer solution with precise matching from electrical performance, structural design to delivery service:
- High-efficiency Design Fully Meeting EU Ecodesign We adopted 100% oxygen-free copper windings and high-grade cold-rolled grain-oriented (CRGO) silicon steel core, with optimized magnetic circuit structure. Both no-load loss and load loss meet and exceed the requirements of EU Ecodesign Tier 2, ensuring long-term energy saving effect and smooth grid access review.
- Climate-adapted Structure for Wide Temperature Range
- Low-temperature adapted mineral insulating oil is selected to ensure normal fluidity and insulation performance at -25°C ambient temperature;
- The radiator layout is optimized to enhance natural heat dissipation capacity, and the winding temperature rise is strictly controlled within the limit of IEC 60076 under 40°C high temperature environment;
- All sealing components use low-temperature resistant fluororubber materials to eliminate oil leakage risk under repeated thermal cycles.
- Precision Customization for Compact Substation Installation We customized the overall dimensions, busbar positions and cable interface sizes strictly according to the client’s prefabricated substation drawings, and the reserved standard interfaces are fully compatible with ABB UniSec series switchgear, which can reduce on-site installation and commissioning time by more than 30%.
1600 kVA Oil-immersed Transformer Technical Specifications
| Parameter Item |
Detailed Specification |
| Rated Power |
1600 kVA |
| Voltage Ratio |
20 ± 2×2.5% / 0.4 kV |
| Vector Group |
Dyn11 |
| Cooling Method |
ONAN (Oil Natural Air Natural) |
| Rated Frequency |
50 Hz |
| Winding Material |
100% Oxygen-free Copper |
| Core Material |
High-grade CRGO Silicon Steel |
| Energy Efficiency Level |
Compliant with EU Ecodesign Tier 2 |
| Short-circuit Impedance |
4% (typical value) |
| Short-circuit Withstand Capacity |
16 kA / 1 s |
| HV Insulation Level |
LI 125 kV / AC 50 kV |
| Operating Ambient Temperature |
-25℃ to +40℃ |
| Tap Changer |
Off-circuit tap changer (±2×2.5%) |
| Standard Protective Devices |
Gas relay, pressure relief valve, oil level indicator, winding temperature indicator |
| Execution Standards |
IEC 60076 series, CE Certified, EU Ecodesign Compliant |
Quality Assurance & Delivery Details
Full-process Factory Quality Control
Every transformer undergoes 12 strict factory inspection items before delivery, including winding DC resistance test, transformation ratio and phase check, insulation resistance test, power frequency withstand voltage test, induced overvoltage test, no-load and load loss measurement, transformer oil chromatographic analysis, sealing leakage test, etc.
All test data are truthfully recorded in the official Mill Test Certificate (MTC), which is delivered together with the goods for client acceptance, local grid filing and project audit.
Delivery & After-sales Service
- Packaging: Export-standard seaworthy wooden case with overall moisture-proof and rust-proof treatment, adapting to long-distance ocean transportation;
- Delivery Terms: Both EXW China factory and CIF Varna, Bulgaria options are available, with full logistics tracking throughout the journey;
- Warranty: 24 months full machine warranty from the date of delivery, with lifetime technical consultation support;
- After-sales Response: 7×24 hour online technical support, supporting remote guidance for installation, commissioning and fault diagnosis.
Project Significance
This successful delivery further verifies GNEE Electric’s product compliance strength and project service capability in the EU renewable energy market. As Bulgaria continues to expand PV and energy storage installations under the EU 2030 renewable energy target, we will continue to provide high-reliability, standard-compliant power transformer solutions for more distributed energy projects in Central and Eastern Europe.
If you are developing PV stations, BESS facilities or grid distribution projects in the EU and require CE-certified, IEC-standard power transformers with customized design support, welcome to
contact our technical sales team. We will provide professional quotation, detailed datasheets and full lifecycle service tailored to your specific project requirements.
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