Overview
Oil-immersed distribution transformers are designed to deliver reliable, safe, and stable power distribution with long-term durability. The product range covers capacities from 30 kVA to 2,500 kVA and voltage ratings from 6 to 35 kV, serving commercial buildings, small industrial facilities, and large residential communities.
The 50–2,500 kVA range is the most widely specified by power utilities, EPC contractors, and commercial projects. Standard ratings cover 50, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1,000, 1,250, 1,600, 2,000, and 2,500 kVA.
Application
Quick Capacity Selection Reference
| Application Scenario | Typical Capacity Range |
| Small shops, restaurants, convenience stores | 50kVA – 160kVA |
| Medium offices, supermarkets, small factories | 200kVA – 500kVA |
| Large commercial complexes, hospitals, small data centers | 630kVA – 1250kVA |
| Residential communities (300–500 households) | 800kVA – 1250kVA |
| Residential communities (800–1000 households) | 1600kVA – 2500kVA |
| Industrial parks, large factories | 1250kVA – 2500kVA |
1. Municipal Grid & Residential Distribution
Applications: Urban feeder substations, rural grid upgrades, residential community power supply
Advantages: Fully sealed outdoor design; low-loss options for lower operating costs
2. Industrial & Manufacturing Facilities
Applications: Production workshops, mining & chemical sites, logistics warehouses
Advantages: 1.2× overload capacity; robust build for harsh industrial environments
3. Commercial Buildings & Public Infrastructure
Applications: Commercial complexes, public venues, small data centers
Advantages: Low no-load loss; stable voltage output; leak-proof sealed structure
4. Renewable Energy & Distributed Generation
Applications: Rooftop PV, distributed energy storage, renewable grid integration
Advantages: S15 ultra-low loss series; strong overload adaptability; IEC compliant
Technical Specifications
| Category | Detailed Specifications |
| Model Series | S11, S13 (Silicon Steel); S15 (Amorphous Alloy) |
| Voltage Grade | HV:10kV/20kV/33kV; LV:0.4kV |
| Frequency | 50Hz / 60Hz for export |
| Capacity Range | 30kVA ~ 2500kVA |
| Connection Group | Dyn11 |
| Short-circuit Impedance | 4% / 6% |
| Cooling Mode | ONAN Oil Natural Air Cooling |
| Oil Type | Standard mineral oil; Natural ester fire-resistant oil optional |
| Tank Structure | Fully sealed corrugated tank, no conservator |
| Overload Capacity | 1.2 times rated load for 2 hours |
| Working Temp | -25℃ ~ +40℃ |
| Key Fittings | Oil level gauge, pressure relief valve, temp indicator, drain valve |
| Standard Complied | IEC 60076, GB/T 6451 |
| Application | Municipal grid, residential area, factory, distributed rooftop PV |
Voltage Grade Comparison
Three standard voltage series are available to match different distribution network levels, project scales and regional grid standards.
| Item | 6–11kV Series | 20kV Series | 33–38.5kV Series |
| Rated Capacity Range | 30 – 2,500 kVA | 30 – 2,500 kVA | 50 – 2,500 kVA |
| High Voltage Options | 6kV / 6.3kV / 10kV / 10.5kV / 11kV | 20kV | 33kV / 35kV / 38.5kV |
| Low Voltage | 0.4kV | 0.4kV | 0.4kV |
| Tapping Range | ±5% / ±2×2.5% | ±5% / ±2×2.5% | ±5% / ±2×2.5% |
| Vector Group | Dyn11, Yzn11, Yyn0 | Dyn11, Yyn0 | Dyn11, Yyn0 |
| Short Circuit Impedance | 4% (≤630kVA)4.5% (800–1600kVA)5% (2000–2500kVA) | 5.5% (≤630kVA)6% (800–2500kVA) | 6.5% (full range) |
| Core Application Scenarios | Urban & rural low-voltage distribution, residential communities, small & medium commercial buildings, rooftop PV | Medium-voltage distribution, long-distance power supply, suburban industrial parks, township grids | High-voltage distribution, large industrial parks, regional grid substations, heavy industrial facilities |
| Key Feature | Most widely used, cost-effective, flexible matching for low-voltage terminal power supply | Balances line loss reduction and investment cost, suitable for 20kV grid areas | Higher voltage level, lower line loss, for large-load and long-distance distribution projects |
Key Technical Features
These distribution transformers adopt graded core designs — standard silicon steel, high-grade silicon steel and amorphous alloy — cutting no-load loss by up to 60%, paired with high-purity copper windings and a fully sealed corrugated tank that passes 100% helium leak testing for dependable outdoor service.
They are engineered with standard Dyn11 vector grouping, voltage-matched short-circuit impedance and 1.2× rated load capacity for 2 hours, delivering stable electrical performance for both grid and industrial applications.
Suitable for -25℃ to +40℃ environments and altitudes up to 1000m, they run on maintenance-free ONAN natural cooling with strong environmental adaptability.
FAQs
1. What is an oil-immersed distribution transformer used for?
Our oil-immersed distribution transformers step down voltage for utility networks, factories, commercial buildings, residential communities, and solar PV projects.
2. What capacity and voltage ratings do you offer?
We offer capacities from 30 kVA to 31,500 kVA and voltage ratings from 6 kV to 35 kV. Common distribution models range from 50 kVA to 2,500 kVA.
3. What is the difference between S11, S13, and S15 transformers?
S11 and S13 models use silicon-steel cores, while S15 models use amorphous-alloy cores. Check the technical datasheets for model-specific energy-loss values.
4. Can you customize oil-immersed distribution transformers?
Yes. We customize capacity, voltage, frequency, vector group, impedance, and accessories to meet your project requirements.
5. What information do you need for a quotation?
Please share your required capacity, primary and secondary voltages, frequency, order quantity, and destination country.
6. What standards and test documents do you provide?
We can provide technical datasheets, drawings, and available test reports. Tell us whether your project requires IEC or GB standards so we can confirm the applicable specifications.
7. What is your minimum order quantity (MOQ)?
Our minimum order quantity is 1 piece, making it easier to order according to your project needs.
8. What is your delivery lead time?
Our delivery lead time is 5–15 days. Contact us to confirm the schedule for your selected model and order.
