dry type isolation transformer
1.Mature and reliable: Adopting a classic epoxy resin casting dry-type structure, it features stable technology, large market application volume, and rich operating experience.
2.Safe and fire-resistant: It is flame-retardant, self-extinguishing, and oil-free, and can be directly installed in load centers, buildings, basements and other places.
3.Moisture-proof and dust-proof: It can operate normally in humid and dusty environments, and can be put into use directly after shutdown without drying treatment.
4.Moderate loss and low noise: With reasonable design, small partial discharge, stable operation, and simple daily maintenance.
5.Environmentally friendly and maintenance-free: No risk of oil leakage, no environmental pollution, basically maintenance-free, and long service life.
Product Details of SCB9 Epoxy Resin Cast Dry-Type Transformer
1. Product Introduction
The SCB9 series three-phase epoxy resin cast dry-type transformer is an iconic and classic model in China’s dry-type transformer industry. Developed by major domestic transformer manufacturers in accordance with the national standard GB/T 10228 and international standard IEC 60076-11, it is one of the most widely applied dry-type transformers for industrial power distribution and commercial & residential buildings.
This product adopts vacuum epoxy casting technology and foil winding structure, replacing the insulating oil used in traditional oil-immersed transformers with epoxy resin composite material as the main insulation medium. It was originally designed to eliminate fire hazards of traditional transformers installed indoors and in crowded areas, and improve operation stability in humid and dusty environments.
After decades of market iteration and technical optimization, the SCB9 series has formed a complete product lineup that satisfies most 10kV distribution network requirements. With outstanding advantages of high maturity, strong adaptability and excellent cost performance, it has become one of the preferred distribution equipments for power grid renovation, industrial projects and civil constructions. The total installed quantity exceeds one million units, with reliable operation in frigid, subtropical, coastal humid and various other climates.
In addition, the SCB9 series can be customized to meet special requirements including low-noise, anti-corrosion, plateau and high-protection versions. It can also be equipped with an intelligent temperature control system, forced air cooling system, protective enclosure and other accessories to further expand application scenarios and operational safety.
2. Technical Specifications(Customizable)
2.1 Main Electrical Parameters
| Item | Specification | Remarks |
Model | SCB9-30～2500/10 | Rating: 30kVA to 2500kVA; Voltage class: 10kV/0.4kV |
Phase | Three-phase | 50Hz |
Rated Capacity | 30, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500 kVA | Full standard range; non-standard ratings available |
Rated Voltage | HV: 10kV (±2×2.5%); LV: 0.4kV | Off-circuit tap adjustment for grid voltage fluctuation |
Connection Group | Dyn11 | Standard for distribution transformers; suppresses 3rd harmonics |
Tap Regulation | Off-circuit tap changer | Simple and reliable; adjusted when de-energized |
Insulation Class | Class F (155℃) | Permissible temperature rise: 100K; actual rise ≤ 80K |
Cooling Mode | AN (Natural Air Cooling) / AF (Forced Air Cooling) | Rated load under AN; 120%~150% short-time overload under AF |
No-Load Loss | Complies with SCB9 level in GB/T 10228-2015 | e.g. ≤ 2.2kW at 1000kVA |
Load Loss | Complies with SCB9 level in GB/T 10228-2015 | e.g. ≤ 10.8kW at 1000kVA (75℃) |
Partial Discharge | ≤10 pC at 1.73Un | Much better than national standard |
Short-Circuit Impedance | 6% (30–1600kVA); 8% (2000–2500kVA) | Excellent short-circuit withstand capability |
2.2 Structural & Environmental Parameters
| Item | Specification |
Winding Structure | HV: epoxy cast foil or wire winding; LV: epoxy cast foil winding (recommended) |
Core Material | High-permeability grain-oriented silicon steel |
Core Structure | Mitered step-lap joint, non-punching binding; low no-load loss and noise |
Protection Degree | Standard IP00; optional IP20, IP23 |
Noise Level | ≤55dB (≤630kVA); ≤60dB (800–1600kVA); ≤65dB (2000–2500kVA) |
Ambient Temperature | -25℃～+40℃ (standard); -40℃～+50℃ (custom) |
Altitude | ≤1000m (standard); ≤4000m (plateau version) |
Installation | Indoor floor-mounted; outdoor compact substation optional |
Standards | GB/T 10228-2015 IEC 60076-11:2013GB 1094.1-2013GB 1094.3-2017 |
3. Main Features
3.1 Outstanding Safety, Eliminates Fire Risks
The SCB9 series completely removes risks of oil leakage, fire and explosion:
Windings are vacuum-cast with epoxy resin, forming a dense, flame-retardant and self-extinguishing insulation system meeting UL94 V-0.
Oil-free design enables safe installation in basements, shopping malls, hospitals and other crowded, high-fire-safety areas.
Optional intelligent temperature monitoring provides over-temperature alarm, trip and automatic fan control.
3.2 Mature Technology, Industry-Leading Short-Circuit Withstand
Low-voltage foil winding offers exceptional mechanical strength and resistance to short-circuit forces.
High-performance grain-oriented silicon steel with mitered joint reduces core loss and noise.
Partial discharge ≤10 pC under 1.73Un, greatly slowing insulation aging and extending service life.
3.3 Strong Environmental Adaptability
Fully encapsulated windings resist moisture, dust, salt fog and condensation; no drying required after shutdown.
Anti-corrosion coating, stainless steel fasteners and toughened insulation are available for chemical and coastal areas.
Low-noise design can reduce noise by 3–5 dB for hospitals, schools and office buildings.
3.4 Excellent Cost Performance
Mature mass production ensures competitive initial cost.
Oil-free and maintenance-free design eliminates oil changing, testing and maintenance.
Optimized loss design and 30-year design life bring low total life-cycle cost.
3.5 Flexible Configuration and Customization
Optional IP23 enclosure, forced air cooling and remote monitoring.
Custom versions: plateau, low-temperature, low-noise.
Suitable for indoor installation, compact substations and direct busbar connection.
4. Applications
4.1 Residential & Commercial Buildings
High-rise residences, shopping malls, hotels, office buildings, hospitals, schools and nursing homes.
4.2 Industrial Facilities
Electronics, food, textile, machinery, mining, cement and chemical plants (anti-corrosion version).
4.3 Public & Transportation Infrastructure
Subways, railways, airports, stadiums, libraries, municipal lighting and wastewater treatment plants.
4.4 Power Grid & Energy Systems
Urban and rural power grid renovation, PV and wind power integration, power plant auxiliary systems.
4.5 Special Custom Applications
Plateau areas, cold regions, laboratories and precision equipment rooms (low-noise version).
