Dry-type transformers are widely used in commercial buildings, industrial facilities, hospitals, and data centers due to their safety, low maintenance, and eco-friendly characteristics. However, selecting the right transformer model requires a solid understanding of technical parameters and model codes.
This guide explains the core parameters of dry-type transformers, provides a detailed model specification table, and offers practical tips for model selection. Whether you're an engineer, purchaser, or project manager, this article will help you make informed decisions.
1. Common Dry-Type Transformer Model Codes
Dry-type transformers are typically named using standard model codes that reflect their insulation type, cooling method, design level, and voltage class. Below are common series and their meanings:
| Model Code | Description |
|---|---|
| SCB10 / SCB11 | Epoxy resin cast, copper winding, low loss, used in power distribution networks |
| SG | Open ventilated dry transformer, aluminum or copper winding, natural air cooling |
| SGB10 | Non-encapsulated dry transformer, better overload capacity |
| SCR | Epoxy cast coil transformer with radial cooling, improved heat dissipation |
Note: The higher the number in the model code (e.g., SCB10 → SCB11), the more optimized the performance (typically in terms of efficiency and noise level).
2. Key Parameters of Dry-Type Transformers
Rated Capacity (kVA): Determines the transformer's load-bearing capability. Common ratings include 100kVA, 250kVA, 500kVA, 1000kVA, 1600kVA, 2500kVA, and 3150kVA.
Primary / Secondary Voltage (V): Typical primary voltages are 10kV, 6kV, or 35kV; secondary voltages are usually 400V or 690V depending on the application.
Connection Group: Common configurations include Dyn11, Yyn0. Dyn11 is most widely used in distribution networks to minimize harmonic interference.
No-load Loss (W): Energy consumed when the transformer is energized without a load. Lower values indicate higher efficiency.
Load Loss (W): Power loss under rated load. This reflects copper loss and affects total energy efficiency.
Impedance Voltage (%): Typically 4%–6%. It influences voltage regulation and short-circuit performance.
Insulation Level: E.g., F-class or H-class. Higher classes support better temperature resistance.
Cooling Method: AN (Air Natural), AF (Air Forced) are common.
3. Sample Dry-Type Transformer Specification Table
The following table showcases the typical parameters of SCB11 series dry-type transformers:
| Model | Rated Capacity (kVA) | Primary Voltage (kV) | Secondary Voltage (V) | No-load Loss (W) | Load Loss (W) | Impedance (%) |
|---|---|---|---|---|---|---|
| SCB11-100 | 100 | 10 | 0.4 | 220 | 1600 | 4.0 |
| SCB11-250 | 250 | 10 | 0.4 | 360 | 3050 | 4.0 |
| SCB11-630 | 630 | 10 | 0.4 | 710 | 6650 | 4.5 |
| SCB11-1250 | 1250 | 10 | 0.4 | 1350 | 12800 | 5.0 |
4. How to Choose the Right Dry-Type Transformer
Define your load requirements. Calculate the total power consumption (in kW) and determine a suitable transformer capacity (in kVA) based on load factor and power factor.
Confirm voltage levels. Match the primary voltage to the utility input and the secondary to your distribution system.
Evaluate installation environment. For indoor use, ensure the transformer is designed for limited ventilation. For high-humidity or dusty environments, consider sealed resin-cast models like SCB series.
Check efficiency level. High-efficiency transformers (like SCB11) reduce energy costs and align with energy codes (such as DOE, IEC, or GB standards).
Review standards compliance. Ensure compliance with relevant standards such as IEC 60076, ANSI, or UL for international projects.
5. Applications of Dry-Type Transformers
Commercial buildings such as office towers, shopping malls, and airports often use dry-type transformers due to their fire safety and low noise.
Industrial facilities including factories, refineries, and data centers benefit from dry transformers' durability and stable performance under heavy loads.
Public infrastructure projects like subways, hospitals, and schools require reliable, low-maintenance power distribution—an ideal use case for dry-type transformers.
Renewable energy systems such as wind farms and solar inverter stations use dry-type transformers for safe and efficient grid connection.
Understanding the model codes and technical parameters of dry-type transformers is essential for correct selection and long-term system performance. By referring to standard parameter tables and aligning with project-specific requirements, users can avoid overcapacity, underperformance, and excessive energy loss.
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