dry-type transformer
1. Energy efficiency level 1: lower losses, best energy-saving effect, greater electricity savings during long-term operation.
2. Ultra-low noise level: optimized iron core, low noise, suitable for hospitals, schools, and residential areas.
3. Safety and fire resistance: oil-free, made of epoxy resin, fire-resistant and explosion-proof, can be installed in indoor distribution panels.
4. Stability and reliability: high short-circuit resistance, low partial discharge, good insulation performance.
5. Weather resistance and maintenance-free: moisture-proof, dust-proof, pollution-resistant, requires no lubrication, longer service life.
I. Product Definition and Applicable Standards
This 35 kV SCB13 epoxy resin dry-type transformer is an ultra-low loss,Andhighly reliable power transformer. It has achieved significant improvements in aspects such as loss control, noise reduction, insulation performance, short-circuit withstand capability, and intelligent monitoring, making it a benchmark product in the 35 kV medium-voltage power distribution field.
35 kV: Rated High Voltage
This transformer complies with the following requirements:
GB 20052-2024 Energy Efficiency Limits and Grades for Power Transformers
GB/T 10228-2015 Dry-Type Power Transformers – Technical Parameters and Requirements
GB 1094.11-2013 Power Transformers – Part 11: Dry-Type Transformers
GB/T 14598.13-2018, GB/T 14099.1-2018
Insulation Class: Class F (maximum operating temperature 155℃)
Insulation level: Class 35 kV – power frequency withstand voltage 70 kV, lightning impulse 170 kV.
Flame retardancy: Class FV-0, non-combustible, no toxic fumes emitted.
Oil-free design eliminates oil leaks, fires, and explosions. It is the preferred equipment for projects with strict environmental safety and fire safety requirements.
II. Key Technical Parameters (Customizable)
Element |
Standard Specification |
Notes |
Rated voltage (HV) |
35 kV, tap range ±2×2.5% |
Adjustment is only made by tapping when power is off; adjustable value ±5%. |
Rated voltage (LV) |
0.4 kV (three-phase four-wire system) |
0.69 kV/1.14 kV (adjustable) |
Rated capacity |
30 kVA–2500 kVA, up to 3150 kVA |
Common values: 100, 200, 400, 630, 1000, 1600, 2000, 2500 kVA |
Connection Group |
Dyn11 (default), Yyn0 (optional) |
Dyn11 — grounding and protection of the distribution network; Yyn0 — high neutral current. |
Cooling Mode |
AN / AF |
AN: 120% of rated load continuously; AF: 150% |
Insulation and temperature rise |
Class F; winding 100 kΩ, core 80 kΩ. |
High thermal resistance, slow aging |
Protection degree |
Standard IP20, IP30/IP40 optional. |
IP20: for clean rooms; IP30: for dust; IP40: for outdoor/coastal areas. |
Frequency |
50 Hz (standard frequency), 60 Hz (customizable frequency) |
For domestic and international projects |
Environmental conditions |
Altitude ≤1000 m; temperature from -25℃ to +40℃; humidity ≤95%. |
Thermal insulation is reduced for use at high altitudes; options with low temperatures and condensation protection are available. |
No-load losses |
Level 1 (GB 20052-2024), 8–10% lower than SCB12, 20% lower than SCB11 |
100 kVA ≈ 250 W; 400 kVA ≈ 650 W; 1000 kVA ≈ 1000 W; 2000 kVA ≈ 1800 W |
Load losses (120℃) |
Level 1 (GB 20052-2024), 5–7% lower than SCB12, 15% lower than SCB11 |
100 kVA ≈ 1650 W; 400 kVA ≈ 4800 W; 1000 kVA ≈ 9200 W; 2000 kVA ≈ 17500 W |
No-load current |
≤1.5% (≥100 kVA) |
Very low reactive losses, high power factor. |
Short-circuit impedance |
6% (default), 4%/8% adjustable |
Excellent short-circuit resistance |
Temperature adjustment |
Intelligent PT100 controller |
Alarm, motion sensor, automatic fan, RS485/Modbus standard. |
III. Design Features
Main unit (optimized for low losses and low noise)
High-permeability grain-oriented silicon steel with thickness of 0.27–0.30 mm
Seven-step stepped lap joint ensures uniform magnetic circuit, lower hysteresis and eddy current losses. Epoxy coating provides moisture resistance, rust and corrosion protection. Non-magnetic fastening and special clamping structure reduce vibration and noise.
Winding (modernized process, high reliability)
Low-voltage winding: high-precision oxygen-free copper foil for uniform current flow and low eddy current losses.
High-voltage winding: multi-layer cylindrical structure with balanced ampere-turn distribution. Vacuum epoxy casting with fiberglass reinforcement, free of bubbles and voids. High mechanical strength, resistant to short circuits and shock waves. Flame-retardant epoxy resin FV-0, emitting no toxic fumes. Partial discharge ≤5 pC.
Cooling and temperature control
Dual cooling mode: AN / AF.
Fans automatically adjust based on winding temperature. PT100 sensors embedded in the windings provide accurate measurement. Intelligent controller: alarm, shutdown, automatic fan control, fault pre-warning. Fiber optic temperature measurement available for high-tech applications.
Intelligent monitoring system
Enclosure and protection
Electrostatically sprayed cold-rolled steel, corrosion-resistant.
Optimized ventilation louvers. Protection rating IP30/IP40, with rainproof cover and dustproof mesh for outdoor use in coastal and polluted areas. Detachable structure for easy maintenance.
Tap changer device and wiring
Sealed, moisture-proof, and dust-proof offline tap changer.
Low-voltage copper terminals for easy installation and expansion. Insulation shields for safety.
IV. Typical Application Areas
Power grid: 35 kV smart substations, urban/rural grid upgrades, industrial parks.
Premium buildings: offices, shopping malls, hotels, subways, airports, hospitals, schools.
Data centers and new energy: data centers, cloud computing, photovoltaic power, wind farms, energy storage stations.
Specialized industries: chemical parks, coal mines, oil refineries, pharmaceuticals, offshore platforms.
Coastal areas with high humidity and abundant salt fog formation.
Environmentally sensitive zones: residential areas, schools, environmental protection zones, green buildings.
