air insulated dry type transformer
1.Better energy efficiency: Class 11 energy efficiency, lower loss than SCB10, more energy-saving during long-term operation.
2.Safety and fire prevention: Oil-free, epoxy casting, flame-retardant and explosion-proof, can be installed indoors/load centers.
3.Stable and reliable: Strong short-circuit resistance, small partial discharge, good insulation performance.
4.Low noise and quiet: Optimized iron core, lower noise, suitable for residential areas and hospitals.
5.Weather-resistant and maintenance-free: Moisture-proof, dust-proof and anti-pollution, oil-free maintenance, longer service life.
Product Details of 35kV SCB11 Epoxy Resin Cast Dry-Type Transformer
I. Product Definition & Applicable Standards
The 35kV SCB11 epoxy resin cast dry-type transformer is a Type 11 low-loss three-phase dry-type distribution transformer, an upgraded version of SCB10. It features significant improvements in no-load/load loss, insulation reliability, noise reduction and short-circuit withstand capability.
Model explanation:
S: Three-phase
C: Epoxy resin cast insulation
B: Foil winding
11: Performance level code, conforming to national Type 11 low-loss standard
This product complies with:
GB/T 10228-2015 Dry-type Power Transformers – Technical Parameters and Requirements
GB 1094.11-2013 Power Transformers – Part 11: Dry-type Transformers
IEC 60076 series
Insulation class: Class F (max operating temperature 155℃)
Fire performance: meets GB/T 14598.13, flame retardance Class FV0, non-flammable, no toxic fumes.
It adopts an oil-free structure that completely eliminates oil leakage, fire and explosion risks, making it ideal for sites with strict environmental and fire protection requirements.
II. Key Technical Parameters(Customizable)
| Item | Standard Specification | Notes |
Rated Voltage (HV/LV) | HV: 35kV, off‑circuit tap ±2×2.5% LV: 0.4kV (3‑phase 4‑wire) | 0.69kV/1.14kV customizable; tap adjustment only when power off |
Rated Capacity | Standard: 30kVA–2500kVA, up to 3150kVA | 100,200,400,630,1000,1600,2000kVA |
Connection Group | Dyn11 (default) | HV delta, LV star with neutral; meets earthing & protection |
Cooling Mode | AN (Natural Cooling) / AF (Forced Cooling) | AN: 120% rated load continuously AF: 150% rated load continuously |
Insulation & Temperature Rise | Class F; winding 100K, core 80K | Vacuum casting + fiberglass; PD ≤10pC |
Protection Degree | IP20 standard, IP30/IP40 optional | IP20: clean indoor; IP40: outdoor/dusty |
Frequency | 50Hz (standard), 60Hz customizable | For domestic & export projects |
Ambient Condition | Altitude ≤1000m; -5℃~+40℃; humidity ≤95% | Insulation derated for high altitude; cold‑resistant optional |
Loss (vs SCB10) | No-load loss ↓12%; Load loss ↓10% | e.g. 1000kVA: no-load ≈1200W, load ≈10000W |
No-load Current | ≤2.5% (≥100kVA) | Lower reactive loss, higher power factor |
Short-circuit Impedance | 6% (default), 4%/8% customizable | Better short-circuit withstand than national standard |
III. Structural Design Features
Core System
High‑quality high‑permeability grain‑oriented cold‑rolled silicon steel (0.30–0.35mm), 45° step‑lap joint.
Epoxy coating for moisture & rust resistance.
Fixed with non‑magnetic straps, low vibration and noise.Noise: 3–4 dB(A) lower than SCB10, generally ≤55 dB(A).
Winding Technology
LV winding: high‑precision copper foil; HV winding: oxygen‑free copper conductor.
Vacuum epoxy casting with fiberglass reinforcement, no bubbles or voids, extremely high mechanical strength.
Uniform current distribution, low eddy current loss.Excellent short-circuit and lightning impulse withstand capability.
Temperature Control & Monitoring
Standard intelligent PT100 temperature controller: over‑temperature alarm, trip, automatic fan control.
Optional RS485 (Modbus) for SCADA/remote platform, supporting unmanned operation.
Sensors embedded inside windings for accurate measurement.
Enclosure & Protection
Cold‑rolled steel with electrostatic spraying, optimized ventilation louvers.
IP30/IP40 with rain/dust protection.
Detachable structure for easy maintenance.Copper terminals with low contact resistance and reliable connection.
Tap Changer & Wiring
Off‑circuit tap changer on HV side, reliable contact.
LV copper bar terminals for easy wiring and expansion.
IV. Core Performance Advantages (vs SCB10)
Higher Energy Saving
Meets Type 11 low-loss standard.
Under 8000h/year, 70% load rate, a 1000kVA unit saves 600–800 kWh/year compared with SCB10, reducing electricity cost greatly over 20-year life cycle.
Safer Fire & Explosion Protection
Oil-free, Class F insulation, FV0 flame retardant, no pollution or toxic gas.
Can be installed directly in building load centers (high-rises, hospitals, subways) without oil pits or fire separation.
Stronger Environmental Adaptability
Fully sealed casting: moisture-proof, dust-proof, salt-fog resistant, anti-condensation.
Stable in coastal, chemical, dusty environments.
No pre-drying required after long shutdown.
High Reliability & Maintenance-Free
Partial discharge ≤10pC, slow insulation aging.
No oil change or refilling needed; only regular cleaning and connection check.
Design life: 25–30 years.
Lower Noise
Optimized core and winding structure, suitable for residential areas, schools, hospitals.
V. Typical Applications
Power grid: 35kV substations, urban/rural grid renovation, industrial park step-down stations
Public buildings: offices, malls, airports, subways, hospitals, schools
Hazardous industry: chemical parks, coal mines, oil refineries, pharmaceuticals
Coastal & high-humidity areas
New energy: small & medium PV/wind farms
VI. Installation, Operation & Maintenance
Installation
Level concrete foundation, good ventilation; inlet/outlet temperature difference ≤15℃.
Reliable grounding (resistance ≤4Ω).
Correct tap position; tightened terminals.
Routine Maintenance
Clean enclosure and fan filters every 3 months.
Check temperature controller functions monthly.
Inspect and tighten electrical connections every 6 months.No oil maintenance required.
Commissioning & Testing
Pre-commissioning tests: insulation resistance, ratio, vector group, DC resistance, withstand voltage.
Preventive tests every 5 years: dielectric loss, partial discharge, insulation evaluation.
Fault Handling
Over-temperature alarm: check load, ventilation and controller.
Trip: check short circuit, overload or insulation fault before restart.
No disassembly by unqualified personnel.
Storage & Transportation
Store in dry, ventilated warehouse; test insulation regularly.
Securely fixed during transport; moisture‑proof, dust‑proof, collision‑free.
VII. Selection & Customization Suggestions
Capacity: Select at 70%–80% load rate, with 15%–20% margin.
Cooling: AN for ≤630kVA & stable load; AF for >630kVA, high temperature or fluctuating load.
Protection: IP20 for clean indoor; IP30 for dusty workshops; IP40 for outdoor/semi-outdoor.
Options: RS485+Modbus for remote monitoring; heating for low temperature; anti-fouling winding for polluted areas.
