air type transformer
1.Ultra energy-saving: 12-level low loss, lower loss than SCB11, more energy-saving during long-term operation.
2.Safer: oil-free, epoxy casting, flame-retardant and explosion-proof, can be installed indoors and in load centers.
3.High reliability: strong short-circuit resistance, small partial discharge, stable insulation performance.
4.Ultra-low noise: optimized iron core, lower noise, suitable for hospitals, schools and residential areas.
5.Maintenance-free: moisture-proof, dust-proof and anti-pollution, no oil maintenance, longer service life.
Product Details of 35kV SCB12 Epoxy Resin Cast Dry-Type Transformer
I. Product Definition & Applicable Standards
The 35kV SCB12 epoxy resin cast dry-type transformer is a Type 12 ultra-low-loss three-phase dry-type distribution transformer, an upgraded version of SCB11.
It further reduces no-load and load loss, improves noise performance and short-circuit withstand capability, while maintaining an oil-free, highly fireproof and explosion-proof structure.
Model meaning:
S: Three-phase
C: Epoxy resin cast insulation
B: Foil winding
12: Performance level, meeting national Level 3 energy efficiency (GB 20052-2020)
Applicable standards:
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 complies with GB/T 14598.13, flame retardant Class FV0, no supporting combustion, no toxic fumes.
Oil-free design eliminates oil leakage and fire risks completely.
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 changer operates only when powered 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; suitable for earthing & relay protection |
Cooling Mode | AN / AF | AN: 120% continuous load; AF: 150% continuous load |
Insulation & Temperature Rise | Class F; winding 100K, core 80K | Vacuum casting + fiberglass; PD ≤10 pC |
Protection Degree | IP20 standard, IP30/IP40 optional | IP20: clean indoor; IP40: outdoor / heavy dust |
Frequency | 50Hz (standard), 60Hz customizable | For domestic and overseas projects |
Ambient Condition | Altitude ≤1000m; -5℃~+40℃; humidity ≤95% | Insulation derated for high altitude; cold-resistant design optional |
Loss Improvement | No-load loss ↓10% vs SCB11; Load loss ↓8% vs SCB11 | 1000kVA: no-load ≈1100W, load(120℃)≈9200W |
No-load Current | ≤2.0% (≥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-permeability grain-oriented cold-rolled silicon steel (0.30–0.35mm), 45° step-lap joint.
Epoxy coating for moisture and rust protection.Fixed by non-magnetic binding straps, low vibration.Noise: 2–3 dB(A) lower than SCB11, generally ≤52 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 performance against short-circuit and lightning overvoltage.
Temperature Control & Monitoring
Standard intelligent PT100 temperature controller: over-temperature alarm, trip, automatic fan control.
Optional RS485 (Modbus) for SCADA and remote monitoring.Sensors embedded in windings for accurate temperature measurement.
Enclosure & Protection
Cold-rolled steel with electrostatic spraying, optimized ventilation louvers.
IP30/IP40 with rainproof and dustproof structure.Detachable enclosure for easy maintenance.Copper terminals with low contact resistance and reliable connection.
Tap Changer & Wiring
Off-circuit tap changer on HV side with stable contact.
LV copper bar terminals for easy wiring and capacity expansion.
IV. Core Performance Advantages (vs SCB10 / SCB11)
Higher Energy Efficiency
Meets Type 12 loss standard and GB 20052 Level 3 energy efficiency.
At 8000h/year, 70% load rate, 1000kVA saves about 500 kWh/year compared with SCB11.
Ultra-Safe & Eco-Friendly
Oil-free, FV0 flame retardant, no toxic gas.
Can be installed directly in building load centers (high-rises, hospitals, subways) without oil pits or fire separation.
Strong Environmental Adaptability
Fully sealed structure: moisture-proof, dust-proof, salt-fog resistant, anti-condensation.
Stable in coastal, high-humidity, heavy-pollution industrial environments.No pre-drying needed after long shutdown.
High Reliability & Maintenance-Free
Partial discharge ≤10 pC, slow insulation aging.
No oil maintenance; only regular cleaning and connection checks.Design service life: 25–30 years.
Ultra-Low Noise
Dual optimization of core and winding, ideal 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 industries: chemical parks, coal mines, oil refineries, pharmaceuticals
Coastal & high-humidity areas
New energy: small & medium PV/wind farm booster stations
VI. Installation, Operation & Maintenance
Installation
Level concrete foundation, good ventilation; air inlet/outlet difference ≤15℃.
Reliable grounding (resistance ≤4Ω).Verify tap position and tighten all terminals.
Routine Maintenance
Clean enclosure and fan filters every 3 months.
Check temperature controller functions monthly.Inspect and retighten electrical connections every 6 months.No oil-related maintenance required.
Commissioning & Tests
Pre-commissioning: insulation resistance, ratio, vector group, DC resistance, withstand voltage.
Preventive tests every 5 years: dielectric loss, partial discharge, insulation aging evaluation.
Fault Handling
Over-temperature alarm: check load, ventilation and controller.
Trip: troubleshoot 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; protect against moisture, dust and collision.
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/IP40 for outdoor or dusty areas.
Options: RS485+Modbus for remote monitoring; heating device for low temperatures; anti-fouling windings for polluted areas.
