China Oil-Immersed Cooling Transformer - Reliable Power Suppliers for Factories and Industrial Use
Product Specification
Basic Information
| Item | Specification |
| Product Model | Example: S11-M-500/10, S13-R-1000/20, S15-H-2500/35 (S=Three-Phase; 11/13/15=Efficiency Class; M/R/H=Structural Type; Capacity kVA/HV kV) |
| Rated Capacity（Sn） | 30kVA~5000kVA (ONAN: 100% rated capacity; ODAF: 130%; ODWF: 160%) |
| Phase/Frequency | Three-Phase (standard); 50Hz/60Hz (±1% tolerance, customizable for 400Hz special use) |
| Connection Group | Dyn11 (default for distribution), Yd11 (for power transformer); Yyn0 (optional) |
| Cooling Type | ONAN (Oil Natural Air Natural) / ODAF (Oil Directed Air Forced) / ODWF (Oil Directed Water Forced) |
Operating & Environmental Conditions
| Parameter | Specification |
| Ambient Temperature | -25℃~40℃ (standard); -40℃~45℃ (low-temperature/high-temperature models with modified oil). |
| Altitude | ≤1000m (derate 5% at 1500m, 10% at 3000m, 15% at 4000m). |
| Humidity | ≤90% @25℃ (no condensation); ≤50% @40℃. |
| Seismic Resistance | GB 50260-2013 / IEC 60076-11, 7-degree intensity (0.15g acceleration); 8-degree optional. |
| Protection Class | IP23 (outdoor, dust/rainproof) / IP20 (indoor). |
Losses & Impedance (Typical Values by Efficiency Class)
| Efficiency Class | Parameter | 500kVA/10kV Example | Test Condition |
| S11 (IEC IE1) | No-Load Loss (Po) | ≤810W | Rated voltage/frequency |
| Load Loss (Pk) | ≤5200W | Rated current, 75℃ | |
| S13 (IEC IE2) | No-Load Loss (Po) | ≤650W (20% lower than S11) | Rated voltage/frequency |
| Load Loss (Pk) | ≤4800W | Rated current, 75℃ | |
| S15 (IEC IE3) | No-Load Loss (Po) | ≤520W (36% lower than S11) | Rated voltage/frequency |
| Load Loss (Pk) | ≤4500W | Rated current, 75℃ | |
| All Classes | Short-Circuit Impedance (Uk%) | 4%~6% (10kV); 6%~8% (35kV) | 75℃, ±10% tolerance |
| No-Load Current (Io%) | ≤1.0% (30~250kVA); ≤0.6% (≥315kVA) | Rated voltage |
ⓘ Efficiency Compliance: GB 20052-2024 Class 2 (S11/S13) / Class 1 (S15); IEC 60076-11 IE1/IE2/IE3
Example S13-500/10 Key Specs
| Item | Value |
| Rated Capacity | 500kVA |
| HV/LV Voltage/Current | 10kV/28.87A; 0.4kV/721.7A |
| No-Load/Load Loss | ≤650W / ≤4800W |
| Short-Circuit Impedance | 4.5% |
| Cooling Method | ONAN |
| Core Material | 30Q130 Silicon Steel |
| Protection Class | IP23 |
ⓘ Customizable for special voltages (e.g., 6.3kV, 13.8kV), high-altitude (≥3000m), or explosion-proof (Ex d IIB T4) requirements. All parameters verified by SGS/Intertek.
Advantages
-
1. Superior Heat Dissipation Efficiency
Leveraging the high thermal conductivity of insulating oil, the transformer efficiently transfers heat generated by internal coils and cores to the tank (and external radiators). This enables stable operation even under high load or long continuous working conditions, preventing overheating-induced component damage and ensuring consistent power output.
-
2. Excellent Insulation Performance
Insulating oil not only dissipates heat but also enhances electrical insulation between internal parts (e.g., coils, iron cores). It effectively isolates air, moisture, and dust, reducing the risk of leakage or short circuits. This advantage makes the transformer highly reliable in humid, dusty, or harsh industrial environments.
-
3. Strong Overload Capacity
The oil-immersed structure and optimized heat dissipation allow the transformer to withstand short-term overloads (e.g., sudden power surges in industrial production or peak civilian electricity use). Its ability to absorb and dissipate excess heat quickly minimizes performance degradation, avoiding unexpected shutdowns.
-
4. Long Service Life
The sealed oil tank protects internal components from external corrosion, dust, and mechanical wear. Additionally, high-quality insulating oil maintains stable performance over time, slowing the aging of coils and insulation materials. The transformer's design life typically exceeds 20 years, reducing the frequency of equipment replacement.
-
5. Low Maintenance Requirements
The sealed structure reduces exposure to external contaminants, lowering the need for frequent internal cleaning or part replacement. Routine maintenance only involves periodic checks of oil level, oil quality, and tank tightness—simplifying operations and cutting long-term maintenance costs.
-
6. Suitable for High-Voltage Scenarios
Due to its excellent insulation and heat dissipation, the Oil-Immersed Transformer is widely used in high-voltage power grids, large industrial plants, and infrastructure projects (e.g., power transmission between substations). It meets strict voltage resistance standards, ensuring safe and efficient high-power transmission.
Product Display
Application
⚡ I. Power System: Core Equipment for High-Voltage Transmission & Distribution
As a cornerstone of power grids, the Oil-Immersed Transformer is indispensable for voltage conversion and power transmission, especially in:
High-voltage power transmission networks: Used in long-distance power transmission between regional power grids (e.g., from power plants to central substations). Its excellent insulation and heat dissipation enable stable operation under high voltage (110kV, 220kV, or even 500kV) and large current, minimizing energy loss during long-distance transmission.
Substation voltage transformation: Installed in primary and secondary substations, it steps down high-voltage power (from transmission lines) to medium/low voltage (10kV, 0.4kV) for subsequent distribution to industrial users and residential areas, matching the voltage requirements of different end-users.
Urban & rural distribution networks: For areas with high power demand or large coverage (e.g., suburban industrial zones, rural townships), it adapts to fluctuating loads and harsh outdoor conditions (temperature changes, humidity), ensuring reliable power supply to scattered users.
⚡ II. Industrial Sector: Reliable Power Supply for Heavy-Duty Operations
Its ability to withstand high loads and harsh environments makes it a top choice for industrial scenarios with continuous, high-intensity power needs:
Heavy industry & manufacturing: Applied in steel mills, chemical plants, and machinery factories, it powers high-power equipment (e.g., blast furnaces, chemical reactors, production lines). Its strong overload capacity copes with sudden power surges during peak production, while its sealed structure resists dust, corrosive gases, and mechanical vibrations.
New energy power generation supporting: Used in solar photovoltaic (PV) and wind power plants as "step-up transformers". It boosts the low-voltage electricity generated by PV panels or wind turbines to high voltage, enabling efficient integration into the national power grid—critical for large-scale new energy utilization.
⚡ III. Civil Infrastructure & Large-Scale Buildings
For civil scenarios requiring stable, long-term power supply and low maintenance, it is widely adopted in:
Large commercial & public buildings: Installed in shopping malls, hotels, hospitals, and airports, it provides continuous power for air conditioning, elevators, lighting, and medical equipment. Its long service life (over 20 years) and low maintenance needs reduce operational costs for building managers.
Data centers: Data centers operate 24/7 with high power density. The Oil-Immersed Transformer's efficient heat dissipation reduces the load on the cooling system (less heat output = lower AC energy consumption), while its stable power supply prevents downtime of servers and data storage devices.
Transportation hubs: Used in high-speed rail stations, subway systems, and ports, it supports the power needs of signal systems, traction power (for trains), and logistics equipment. Its resistance to temperature fluctuations and humidity ensures reliable operation in outdoor or semi-outdoor installations.
⚡ IV. Special Harsh Environments
Its robust sealed structure and corrosion resistance make it suitable for challenging conditions:
Mining & oilfields: In underground mines or remote oilfields, where environments are humid, dusty, or exposed to corrosive substances, the transformer's insulation oil and sealed tank protect internal components from damage, ensuring power supply for mining machinery or oil extraction equipment.
Remote off-grid systems: For isolated areas (e.g., mountainous villages, island communities) with independent power systems (powered by small hydropower or diesel generators), the transformer's low maintenance requirements and long lifespan reduce the need for frequent on-site repairs, ensuring stable daily power.
Frequently Asked Questions
Q What is the difference between S11, S13, and S15 oil-immersed transformers?
A S11, S13, and S15 refer to different energy efficiency classes. S11 meets IEC IE1 standard, S13 meets IE2 (with approximately 20% lower no-load loss than S11), and S15 meets IE3 (with approximately 36% lower no-load loss than S11). Higher efficiency classes result in lower energy consumption and operating costs over the transformer's lifetime.
Q What cooling methods are available for oil-immersed transformers?
A Three main cooling methods are available: ONAN (Oil Natural Air Natural) for standard operation at 100% rated capacity; ODAF (Oil Directed Air Forced) for enhanced cooling at up to 130% capacity; and ODWF (Oil Directed Water Forced) for heavy-duty applications at up to 160% rated capacity. The appropriate method depends on load requirements and installation environment.
Q Can oil-immersed transformers be used at high altitudes or in extreme temperatures?
A Yes. Standard models are rated for altitudes up to 1000m and ambient temperatures of -25℃ to 40℃. For high-altitude installations, derating is applied (e.g., 10% at 3000m). Special low-temperature or high-temperature models with modified insulating oil are available for environments ranging from -40℃ to 45℃. Custom high-altitude versions (≥3000m) are also available upon request.
Q How long is the service life of an oil-immersed transformer, and what maintenance is required?
A The design life of our oil-immersed transformers typically exceeds 20 years. Routine maintenance is minimal and includes periodic checks of oil level, oil quality (dielectric strength), and tank seal integrity. The sealed structure significantly reduces exposure to contaminants, lowering the need for frequent internal cleaning or component replacement.
Q Are these transformers suitable for use in hazardous or explosion-risk environments?
A Yes. Explosion-proof variants certified to Ex d IIB T4 standards are available for use in mining, oilfields, chemical plants, and other hazardous locations. The robust sealed tank and high-grade insulating oil provide reliable protection against dust, moisture, and corrosive substances in demanding industrial environments.
Q Can the transformer specifications be customized for special application requirements?
A Absolutely. We offer full customization including special voltage levels (e.g., 6.3kV, 13.8kV), non-standard frequencies (e.g., 400Hz), alternative connection groups (Dyn11, Yd11, Yyn0), explosion-proof ratings, and high-altitude configurations. All custom parameters are verified and certified by internationally recognized bodies including SGS and Intertek.