Step Up Transformer
1.High Efficiency & Energy Saving
No-load loss reduced by over 30% and no-load current decreased by 70–85% compared with S9 series, greatly lowering annual operating electricity cost.
2.Low Noise & High Reliability
Adopts high-quality cold-rolled silicon steel sheet with full-step hole-free binding, ensuring low noise and stable operation. Fully sealed structure prevents oil leakage and realizes maintenance-free operation.
3.Excellent Short-Circuit Withstand Capability
Equipped with oxygen-free copper windings and rigid structure, featuring strong resistance to short circuits and grid impact.
4.Long Service Life
Low temperature rise slows down insulation aging, prolonging service life and reducing overall operation and maintenance cost.
5.Wide Applicability
Suitable for 110kV power transmission, industrial and urban power grids, with stable operation and easy maintenance.
110kV S11 Series Oil-Immersed Power Transformer
1. Product Overview & Positioning
This series is mainly used in 110kV high-voltage power transmission and distribution systems, responsible for power conversion, distribution and transmission between 110kV high voltage (115kV, 121kV customizable) and 10kV/35kV low voltage. It is key equipment connecting regional power grids, industrial loads and urban distribution networks.
With high efficiency, energy saving, stability, reliability and maintenance-free advantages, it is widely used in key substations, large industrial parks, urban core distribution networks, metallurgy, chemical industry, new energy supporting systems and other places demanding high power supply stability and energy efficiency. It is one of the most widely applied and cost-effective oil-immersed transformers at 110kV level.
Model Explanation
S: Three-phase power transformer, suitable for industrial and grid three-phase power supply.
11: Performance code representing low-loss level, with significantly improved loss indexes compared with S9 and S10 series.
110kV: Rated high voltage, mainly for 110kV power transmission and distribution systems.
Typical model: S11-10000/110
10000: Rated capacity 10000 kVA
110: Rated high voltage 110 kV
Compliance Standards
In addition to national standards, the product complies with IEC 60076 international standards, passes authoritative tests of the national power industry, meets flame retardant requirements in GB/T 25287, and adopts transformer oil in line with GB/T 7595, ensuring compliance and safety under various working conditions.
2. Core Technical Parameters(Customizable)
Item
| Standard Specification (Typical) | Application & Notes | |
Rated Capacity | 6300, 8000, 10000, 12500, 16000, 20000, 31500, 40000, 50000, 63000, 100000, 120000, 180000 kVA | 6300–20000kVA for industrial parks & urban grids; 31500kVA+ for key substations |
Rated Voltage | HV: 110/115/121kV (±2×2.5% off‑load tap changing); LV: 10kV/35kV (6kV customizable) | Off‑load regulation for stable grids; on‑load version (SZ11) available for frequent voltage adjustment |
Connection Group | YNd11 (standard), YNyn0 (optional) | YNd11 features strong short-circuit withstand ability |
Short-circuit Impedance | 10.5% (6300–10000kVA); 12% (12500–20000kVA); 14% (31500kVA+) | Customizable for grid safety |
No-load Loss | ≥30% lower than S9; ≤12.8kW for 10000kVA; meets Class 2 energy efficiency | Outstanding energy saving under light load or no-load |
Load Loss (75℃) | ≤62kW at rated load for 10000kVA/110kV, complies with GB/T 6451 | High efficiency under heavy load |
No-load Current | ≤0.5% (≥10000kVA); ≤0.6% (6300–8000kVA) | Low reactive power loss |
Insulation Level | HV: lightning impulse 450kV, AC withstand 200kV; LV: lightning impulse 75kV, AC withstand 35kV | Strong resistance to lightning and switching overvoltage |
Cooling Mode | ONAN, ONAF; OFAF customizable for large capacity | ONAF supports 150% rated load |
Noise Level | ≤60dB(A) for 10000kVA; ≤65dB(A) for 31500kVA+ (ONAN) | Suitable for residential & urban areas |
Partial Discharge | ≤100pC; ≤50pC for large capacity | Slow insulation aging, long service life |
Oil Standard | 25# transformer oil (GB/T 2536), breakdown voltage ≥35kV | Excellent insulation and heat dissipation |
Ambient Range | Temp: -30℃～+45℃; altitude ≤1000m (up to 4000m customizable); humidity ≤95% | Adaptable to plateau, cold, humid environments |
Design Life | ≥30 years | 5–10 years longer than S9 series |
Energy-saving example:
For 10000kVA/110kV, 8000 operating hours/year, 70% load rate, it can save about 15,000–20,000 RMB per year compared with S9 series, with a payback period of only 3–5 years.
3. Structure & Technical Features
3.1 Core (Low Loss & Low Noise)
Adopts high-permeability grain-oriented cold-rolled silicon steel sheet (0.27–0.30mm).
Multi-step 45° step-lap joint, 3-limb or 5-limb structure, lamination factor ≥0.96.
Hole-free binding to reduce vibration and noise.
Phosphating and painting for moisture-proof, rust-proof and anti-corrosion.
Wound core available for lower noise and no-load current.
3.2 Winding Structure (High Reliability & Short-Circuit Resistance)
High-quality oxygen-free copper conductors with low resistivity and loss.
HV winding: multi-layer cylindrical type with uniform insulation and balanced ampere-turns.
LV winding: spiral or continuous type for large current and good heat dissipation.
Vacuum drying and impregnation; end reinforcement to reduce partial discharge.
CNC winding with tolerance ≤±0.5mm.
3.3 Tank & Sealing (Leak-Proof & Maintenance-Free)
High-quality Q235B steel plate, welded by automatic submerged arc welding, tested by ultrasonic inspection.
Elliptical or rectangular tank; corrugated or panel radiator.
Fully sealed structure with capsule or diaphragm to isolate oil from air.
Three-layer primer and one top-coat painting for outdoor anti-corrosion.
3.4 Insulation & Protection System
Composite insulation system (pressboard, oil, epoxy parts), insulation class A (105℃).
Standard protections: Buchholz relay, pressure relief valve, oil level gauge, thermometer.
Optional: DGA online monitoring, lightning protection.
Rigid fixing to prevent displacement during transportation and operation.
3.5 Cooling System
ONAN: natural convection, low noise, suitable for medium and light load.
ONAF: auto-controlled fans, heat dissipation improved by over 50%.
OFAF available for large-capacity, heavy-duty applications.
Intelligent temperature control and fault alarm.
4. Core Product Advantages
Ultra-high energy efficiency & remarkable economic benefit
No-load loss reduced by ≥30%, no-load current reduced by 70%–85%, load loss reduced by 10%–15% compared with S9. It greatly reduces electricity cost and reactive power loss, in line with national “dual carbon” policy.
Low noise & eco-friendly
Noise ≤60–65dB(A), fully compliant with urban and residential requirements. Environmental oil, fully sealed, no leakage or pollution.
Excellent short-circuit withstand capability
High mechanical strength windings and rigid structure can withstand 25–30 times rated short-circuit current. Complete protection ensures stable and safe operation.
Fully sealed & maintenance-free
Oil isolated from air, stable oil quality, no frequent oil replacement or testing. Maintenance cost reduced by over 60%. Service life ≥30 years.
Strong environmental adaptability
Works stably in -30℃～+45℃; customizable for plateau, low temperature, salt fog, corrosion. Outdoor IP33 protection.
Premium materials & reliable quality
Strict quality control in materials and manufacturing. Full type tests before delivery to ensure compliance with national standards.
5. Application Scenarios
Power Grid: 110kV key substations, regional power supply, urban distribution network upgrading.
Large Industry: metallurgy, chemical, mining, cement, paper, heavy-load continuous production.
Urban Construction: commercial districts, residential quarters, subway, airport, high-speed rail stations.
New Energy: PV and wind power 110kV collection and boosting stations.
Special Environments: plateau, cold regions, coastal salt fog, chemical corrosive areas.
6. Installation, Operation & Maintenance
6.1 Installation
Flat, well-ventilated, well-drained site away from fire sources.
Reinforced concrete foundation with level error ≤2mm/m.
Professional hoisting and anti-shock transportation.
Reliable earthing (earth resistance ≤4Ω).
Full insulation and function tests before commissioning.
6.2 Operation
Real-time monitoring of oil temperature, oil level, current, voltage and noise.
Avoid long-term overload.
Keep radiators clean.
Troubleshoot immediately upon alarm.
6.3 Maintenance
Weekly inspection of oil level, temperature and sealing.
Annual oil test; periodic insulation and partial discharge tests.
Regular operation during long-term outage to prevent moisture.
7. Supply & After-Sales Service
7.1 Scope of Supply
Transformer body, HV/LV bushings, Buchholz relay, pressure relief valve, oil level gauge, thermometer, cooling system, terminals, manual, test report and certificate. Customization for capacity, voltage, cooling and protection is available.
7.2 Factory Tests
No-load test, load test, insulation resistance, DC resistance, induced withstand voltage, lightning impulse, partial discharge, temperature rise test, etc.
7.3 After-Sales Service
On-site installation guidance and commissioning.
Warranty: 1–3 years, free repair and replacement for quality defects.
Periodic maintenance guidance and testing.
24-hour emergency response.
Professional technical training for operation and maintenance.
8. Product Summary
The 110kV S11 series oil-immersed power transformer is a classic, energy-saving, safe, reliable, low-noise, eco-friendly and maintenance-free power transmission and distribution equipment. It achieves comprehensive upgrades in loss, reliability and maintainability based on the S9 series, reaching Class 2 or higher energy efficiency.
With premium materials, sophisticated technology, complete protection and strong environmental adaptability, it is widely applicable to power grids, industry, urban construction and new energy. It satisfies heavy-duty and continuous operation while greatly reducing operating and maintenance costs, making it an optimal choice for 110kV power transmission and distribution.
