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The oil immersed power transformer is a core distribution equipment for medium and large substations, strictly adhering to IEC and GB/T 1094 standards. Utilizing mineral or eco-friendly oil insulation coupled with multi-stage cooling systems (ONAN, ONAF, OFAF), oil filled power transformer delivers exceptional insulation, high cooling efficiency, and large-capacity operational stability. Oil type power transformer is the premier choice for industrial hubs, urban grid centers, renewable energy step-up stations, and municipal backbone substations. Capable of long-term reliable operation in standard climates (-30℃ to 45℃), as an oil immersed power transformer manufacturer our oil type power transformer also supports custom configurations for high altitudes (≤4500m) and severe environments.
Core Parameters:
• Energy Efficiency: Tier 2 or Tier 1 (GB 20052-2024), lowering no-load losses by 15%~20%.
• Structure: Mineral/Eco Oil Immersion + Multi-Stage Cooling + Compact Substation-Grade Tank.
• Warranty: 5-Year Comprehensive Warranty.
Product Features
High-quality mineral/eco oil isolates environmental erosion. Equipped with Buchholz relays and pressure relief valves for rapid fault isolation and ultimate substation safety.
Advanced Tier 2+ efficiency with premium CRGO steel and optimal copper windings reduces losses by 15-20%. The sealed tank yields a design lifespan of over 30 years.
Covers 500kVA to 20000kVA across 10kV~110kV grids. Optional on-load tap changing (±8%/±10%) precisely adapts to grid fluctuations ensuring power stability.
Modular design suitable for indoor or outdoor substation layouts. Robust 1.3x overload capacity for 30 minutes seamlessly handles short-term distribution peaks.
Core components utilize mature, reliable technologies yielding ultra-low failure rates. Simple, periodic visual and oil quality checks keep long-term O&M costs down.
Can be equipped with integrated smart monitoring modules for remote tracking of winding temp, oil level, and load currents, enabling predictive digital maintenance.
Enjoy full-lifecycle support including precise pre-sales capacity and cooling configuration guidance, on-site installation support, and a solid 5-year warranty.
Key Specifications (500kVA~20000kVA)
| Parameter | Typical Value | Description |
| Rated Capacity | 500kVA ~ 20000kVA | Long-term safe apparent power satisfying centralized demands of medium/large substations. |
| Rated Voltage | HV: 10/35/110kV | LV: 0.4/6/10kV | Customizable voltage inputs and outputs supporting up to 110kV high-voltage grids. |
| Vector Group | Dyn11 / Yyn0 / YNyn0 | Mainstream connections adaptable to diverse 3-phase systems; bespoke setups available. |
| Impedance | 4% ~ 10.5% | Substation-grade specification that effectively limits short-circuit impact. |
| No-Load Loss | ≤ 0.8kW ~ ≤ 15kW | Tier 2/Tier 1 compliant. Extremely low idle loss saves substantial OPEX. |
| Load Loss (120℃) | ≤ 4.5kW ~ ≤ 85kW | Optimized copper cross-sections paired with high-efficiency oil flow reduce waste. |
| Winding Temp. Rise | ≤ 65K (Class A) | Multi-stage cooling synergistically limits heat generation, protecting oil from degradation. |
| Noise Level | ≤ 58~65dB(A) | Low-noise joints and shock-absorbing mounts maintain a quiet substation footprint. |
| Cooling Method | ONAN / ONAF / OFAF | Natural cooling covers daily needs; forced air/oil setups can boost capacity safely by 15-30%. |
| Protection Level | IP20 (Indoor) ~ IP54 (Outdoor) | Substation-grade sealed tank ensures zero ingress of foreign matter, rain, or dew. |
Detailed Description
The oil immersed power transformer (encompassing mainstream S11/S13 and SZ11 On-Load Tap Changing series) is a highly efficient 3-phase distribution workhorse, representing the backbone of domestic medium and large substation networks. Oil filled power transformer core advantage stems from exceptional insulation properties, broad capacity scaling, and rock-solid operational stability under heavy centralized loads.
The insulation architecture of the oil immersed power transformer fully immerses the core and windings in high-grade mineral or eco-friendly oil, which acts as a superior dielectric and thermal conductor. This complete immersion shields vital components from air, moisture, and dust, significantly slowing down insulation aging. The sealed corrugated or radiator-type tank features critical safety instruments—including gas relays and pressure valves—guaranteeing oil integrity and preventing leaks. Inside, the imported high-permeability cold-rolled grain-oriented silicon steel core is assembled via a 45-degree full-mitre step-lap process. Combined with precision-wound low-resistance copper windings, this oil type power transformer achieves a partial discharge of ≤10pC, a 30+ year lifespan, and relentless performance in extreme environments ranging from -30℃ to 45℃.
S20 Series Core Parameters & Scenarios
| Parameter | Typical Value | Description |
| Energy Efficiency | GB 20052-2024 Tier 2 (NX2) | Meets strict efficiency mandates, perfect for municipal grids and renewable step-up stations. |
| No-Load Loss | Approx. 0.9kW ~ 16.0kW | Highly economical idle power draw. |
| Load Loss (120℃) | Approx. 5.0kW ~ 90.0kW | Maintains efficiency even across large-scale transmissions. |
| Partial Discharge | ≤ 10pC | Guarantees excellent long-term insulation safety. |
| Structure | ONAN/ONAF + Sealed Tank | Includes pressure/temp gauges, gas relays, and supports optional OLTC and smart meters. |
| Applicable Scenarios | Load ≤ 65%, Budget-focused | Ideal for township main stations, large commercial hubs, industrial plants, and high-rise auxiliary substations operating under 110kV. |
Standard S20 Series Technical Reference (10kV Class)
| Capacity (kVA) | Impedance (%) | No-Load Loss (W) | Load Loss (W) | No-Load Current (%) | Oil Weight (kg) | Total Weight (kg) | Dimensions W×D×H (mm) | Gauge (mm) |
| 50 | 4.0 | 100 | 830 | 1.2 | 115 | 550 | 830×600×970 | 400 |
| 100 | 4.0 | 135 | 1265 / 1200 | 0.8 | 130 | 640 | 970×750×1050 | 400 |
| 200 | 4.0 | 215 | 2185 / 2060 | 0.7 | 190 | 900 | 1200×1000×1050 | 550 |
| 315 | 4.0 | 305 | 3065 / 2920 | 0.6 | 250 | 1300 | 1500×1150×1205 | 660 |
| 500 | 4.0 | 430 | 4830 / 4120 | 0.6 | 340 | 1800 | 1630×1250×1250 | 660 |
| 800 | 4.5 | 630 | 6000 | 0.5 | 376 | 2000 | 1700×1400×1700 | 820 |
| 1250 | 4.5 | 870 | 9600 | 0.5 | 450 | 3600 | 2200×1500×1900 | 820 |
| 1600 | 4.5 | 1050 | 11600 | 0.5 | 540 | 4300 | 2250×1800×2200 | 820 |
| 2000 | 5.0 | 1225 | 14640 | 0.4 | 800 | 5100 | 2300×2100×2300 | 820 |
| 2500 | 5.0 | 1440 | 18840 | 0.4 | 860 | 7200 | 2350×2100×2500 | 820 |
* The table above showcases the standard 10kV S20 series platform parameters. For large-scale substation models extending up to 20000kVA or 35kV/110kV voltage levels, dimensions, weights, and electrical properties are heavily customized based on specific project and grid criteria.
FAQ
It is also widely called oil filled power transformer and oil type power transformer. This equipment uses insulating oil for cooling and insulation, ideal for outdoor power grid, industrial and renewable energy power transmission projects with high voltage demands.
For oil filled power transformer and oil type power transformer, the oil insulates windings to avoid electric breakdown and dissipate operating heat. Stable oil status guarantees long-term safe running and reduces internal fault risks of the power transformer.
Proper annual oil testing extends the lifespan of oil filled power transformer and oil type power transformer to 25–40 years. Timely oil filtration and leak inspection can effectively slow insulation aging for the oil immersed power transformer.
Oil filled power transformer and oil type power transformer fit power stations, mining zones and urban distribution networks. The excellent heat dissipation feature of oil immersed power transformer supports continuous heavy-load operation in open-air harsh working environments.
We support full customization of oil filled power transformer and oil type power transformer, including capacity, voltage grade and cooling mode. Our oil immersed power transformer complies with IEC, IEEE and local power industry standards for global projects.
Whatsapp: +86-13961294414
E-mail: junqiu.wang@czguanghui.cn
jocelyn.duan@czguanghui.cn
ADD: No. 1, Yulong Middle Road, Xuejia Town, Xinbei District, Changzhou City, China
Mobile: 0086-15380068868
