dry-core transformer
1. Level 1 energy efficiency: less loss, best energy saving effect, greater energy saving in long-term use.
2. Ultra-low noise: Optimized iron core, low noise, suitable for hospitals, schools and residential areas.
3. Safety and fire resistance: Oil-free, made of epoxy resin, fireproof and explosion-proof, can be installed in indoor distribution boards.
4. Stability and reliability: high short-circuit resistance, small partial discharge, good insulation performance.
5. Weatherproof and maintenance-free: moisture-proof, dust-proof, anti-pollution, no lubrication required, longer service life.
I. Product Definition and Applicable Standards
This 35kV SCB13 epoxy resin dry case transformer is an ultra low lossAnd highly reliable power transformer. It achieves significant improvements in aspects such as loss control, noise reduction, insulation performance, short circuit resistance and intelligent monitoring, making it the benchmark product in the 35 kilovolt medium voltage power distribution industry.
35 kV: Rated high voltage
This transformer meets the following requirements:
GB 20052-2024 Limit values and energy efficiency levels 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 working temperature 155℃)
Insulation level: class 35 kV – withstand industrial frequency 70 kV, lightning impulse 170 kV.
Fire resistance: class FV-0, does not support combustion, does not emit toxic fumes.
The oil-free design eliminates oil leaks, fires, and explosions. It is the preferred equipment for projects with stringent environmental and fire safety requirements.
II. Key technical parameters (customizable)
Element |
Standard Specification |
Notes |
Nominal voltage (HV) |
35 kV, branch from the circuit ±2×2.5% |
Adjustment is only by touching when the power is off; the adjustable value is ±5%. |
Nominal voltage (LV) |
0.4 kV (three-phase four-wire system) |
0.69 kV/1.14 kV (adjustable) |
Nominal lifting 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 current in the neutral. |
Cooling mode |
AN / AF |
AN: 120% rated load continuously; AF: 150% |
Insulation and temperature increase |
Class F; winding 100 kOhm, core 80 kOhm. |
High temperature resistance, slow aging |
Degree of protection |
IP20 standard, IP30/IP40 optional. |
IP20: for clean rooms; IP30: for dust; IP40: for outdoor/coastal use. |
Frequency |
50Hz (standard frequency), 60Hz (custom frequency) |
For domestic and international projects |
Environmental conditions |
Altitude ≤1000 m; temperature from -25℃ to +40℃; humidity ≤95%. |
Insulation is reduced for use at higher altitudes; low temperature and condensation-resistant options are available. |
Idle 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% customizable |
Excellent short circuit resistance |
Temperature adjustment |
PT100 intelligent controller |
Alarm, motion sensor, automatic fan, RS485/Modbus standard. |
III. Features of the design solution
Main unit (optimized for low loss and low noise)
Highly permeable grain-oriented silicon steel with a thickness of 0.27–0.30 mm
The seven-stage, stepped, overlapping connection ensures a uniform magnetic circuit, reduced hysteresis, and eddy current losses. The epoxy coating provides moisture resistance and protection against rust and corrosion. The non-magnetic mounting and special clamping design 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 loss.
High voltage winding: multi-layer cylindrical structure with a balanced number of ampere-turns. Vacuum epoxy casting with fiberglass reinforcement, without bubbles and voids. High mechanical strength, short-circuit and shock wave resistance. Flame-retardant epoxy resin FV-0, does not emit toxic fumes. Partial discharge ≤5 pC.
Cooling and temperature control
Dual cooling mode: AN / AF.
The fans are automatically controlled based on winding temperature. PT100 sensors built into the windings ensure accurate measurement. The intelligent controller features alarms, shutdowns, automatic fan control, and fault pre-warning. Temperature measurement via fiber optics is available for high-tech applications.
Intelligent monitoring system
Fencing and protection
Cold rolled steel with electrostatic spraying, corrosion resistant.
Optimized ventilation louvers. IP30/IP40 protection rating, with a rain cover and dustproof mesh for outdoor use, coastal use, and polluted areas. Disassemblable design for easy maintenance.
Tap changer and wiring
The tap changer operates autonomously and is sealed, moisture-proof and dust-proof.
Low voltage copper terminals for easy installation and expansion. Isolation screens for safety.
Ⅳ.Typical areas of application
Energy network: 35 kV smart substations, modernization of urban/rural networks, industrial parks.
Elite buildings: offices, shopping centers, hotels, metro, airports, hospitals, schools.
Data centers and new energy sources: data centers, cloud computing, photovoltaics, wind power plants, energy storage stations.
Specialized industries: chemical parks, coal mines, oil refineries, pharmaceuticals, offshore platforms.
Coastal areas with high humidity and abundant formation of salt fog.
Environmentally sensitive areas: residential areas, schools, environmental protection areas, green buildings.
