Please Choose Your Language
Views: 0 Author: Site Editor Publish Time: 2026-06-29 Origin: Site
A typical utility-scale solar project with an installed capacity of 20 MW may use eight 2500 kVA oil immersed distribution transformers to connect inverter stations to the medium-voltage collection network.
Typical transformer configuration:
Item | Specification |
|---|---|
Rated Capacity | 2500 kVA |
Primary Voltage | 33 kV |
Secondary Voltage | 0.8 kV |
Frequency | 50 Hz |
Cooling Method | ONAN |
Vector Group | Dyn11 |
Tap Changer | ±2 × 2.5% Off-load |
Impedance | 6% |
Standard | IEC 60076 |
This configuration is widely used because it offers a good balance between equipment cost, system efficiency, and ease of maintenance.
Below is a representative set of technical data commonly specified for distribution transformers in utility and industrial projects.
Parameter | Typical Value |
|---|---|
Rated Capacity | 2500 kVA |
Rated Voltage | 33/0.4 kV |
No-load Loss | ≤2.65 kW |
Load Loss (75°C) | ≤23.5 kW |
No-load Current | ≤0.4% |
Short-circuit Impedance | 6% |
Efficiency at Full Load | Approximately 99.0% |
Total Weight | 5,800–6,500 kg |
Oil Weight | 1,450–1,700 kg |
Copper Weight | 720–850 kg |
Sound Level | ≤55 dB |
Ambient Temperature | -25°C to +45°C |
Installation Altitude | ≤1000 m (higher altitude available on request) |
These values may vary depending on customer specifications, local utility requirements, and efficiency class.
Transformer losses occur every hour the unit is energized, regardless of whether it is operating at full load.
For example, reducing the no-load loss from 3.2 kW to 2.65 kW saves approximately 4,800 kWh of electricity per year.
Over a 30-year operating life, the cumulative energy savings exceed 140,000 kWh for a single transformer, helping utilities reduce operating costs while improving overall network efficiency.
For projects involving multiple transformers, the savings become even more significant.
Distribution transformers exported to tropical and desert regions are often designed to operate under demanding environmental conditions.
Typical design requirements include:
Ambient temperature up to 45°C
Relative humidity up to 95%
Installation altitude below 1000 m
UV-resistant outdoor coating
Anti-corrosion treatment for coastal environments
Protection against dust and heavy rainfall
These features help ensure reliable operation in regions such as West Africa, Southeast Asia, and the Middle East.
Before shipment, every transformer should undergo routine testing in accordance with IEC 60076.
A standard testing procedure includes:
Test Item | Acceptance Requirement |
|---|---|
Turns Ratio Test | Within IEC tolerance |
Winding Resistance | Phase balance verified |
Applied Voltage Test | No flashover or breakdown |
Induced Voltage Test | Passed |
Insulation Resistance | Meets specification |
No-load Loss Test | Within guaranteed value |
Load Loss Test | Within guaranteed value |
Oil Dielectric Strength | ≥60 kV |
Leak Test | No leakage after pressure inspection |
Each transformer is supplied with a factory test report to facilitate site acceptance and commissioning.
Oil immersed distribution transformers are commonly used in projects such as:
Industrial Manufacturing Park
A manufacturing complex with a peak demand of 8 MW may use four 2000 kVA transformers to distribute power to production lines, compressors, and HVAC systems. Parallel operation improves reliability and allows maintenance without interrupting the entire facility.
Mining Project
Remote mining sites often select 2500–3150 kVA transformers because of their strong overload capability and stable performance under continuous heavy-duty operation.
Solar Power Plant
In a 50 MW photovoltaic project, multiple 2500 kVA transformers are typically installed near inverter stations to step up the voltage from 800 V to 33 kV, enabling efficient transmission to the collection substation while minimizing cable losses.
