How to Choose the Right Dry-Type Transformer Model?
Time：2025-07-2 Auther：ZTelec-www.ztelectransformer.com
Choosing the right dry-type transformer is a critical step in ensuring safe, efficient, and cost-effective power distribution. Factors such as load characteristics, energy efficiency standards, environmental conditions, installation complexity, and long-term cost should all be taken into account. This guide outlines the key considerations to help users make an informed selection.
1. Determine Load Requirements
1.1 Calculate Transformer Capacity
Transformer capacity can be estimated based on the total power (kW) of the load and the power factor (typically 0.8–0.9):
Capacity (kVA) = Total Power (kW) ÷ Power Factor
For example, a system with 500 kW total load and 0.85 power factor requires approximately 588 kVA, thus a standard 630 kVA transformer would be selected. A safety margin of 20–30% is recommended to avoid long-term overload.
1.2 Analyze Load Type
Continuous Load: For constant high loads (e.g., factories), SCB12 or SCB18 models offer high thermal endurance.
Intermittent Load: Lighting or HVAC systems can use economical models like SCB10.
Shock Load: Applications like welding require transformers with strong short-circuit strength, such as SCB13+ series.
2. Match Energy Efficiency Standards
According to China’s GB 20052-2020 energy efficiency classification:
| Efficiency Level | Recommended Applications | Typical Model | Energy-Saving Compared to SCB10 |
|---|---|---|---|
| Level 1 | Data centers, shopping malls | SCB18 | No-load loss ↓30%, load loss ↓10% |
| Level 2 | Industrial and commercial | SCB14 | No-load loss ↓15%, load loss ↓5% |
| Level 3 | Temporary power, budget-driven | SCB10 | Basic efficiency, low cost |
Recommendation: For long-term and high-utilization scenarios, prioritize Level 1 or Level 2 models. For short-term use or low-load systems, Level 3 transformers are more economical.
3. Consider Environmental Conditions
3.1 Temperature and Humidity
High temperature zones: Use SGB10 transformers with H-class insulation (220°C rating).
High humidity or corrosive areas: SG10 resin-insulated models provide superior moisture and chemical resistance, ideal for coastal and chemical plants.
3.2 Fire Safety
Public facilities: In schools, hospitals, and crowded places, SCB12 or SCB18 epoxy cast transformers offer flame-retardant, explosion-proof performance.
Outdoor substations: SCB14 models with secondary-level energy efficiency provide stable operation where fire separation is limited.
3.3 Space Limitations
Compact spaces: For tunnels and basements, choose rectangular SCB12 transformers or modular units.
Low-noise areas: SGB10 dry transformers are designed for silent operation, suitable for labs and data centers.
4. Evaluate Installation and Maintenance
4.1 Installation Method
Indoor: SCB series (IP23 or above) protects against dust and moisture.
Outdoor: Use SCB13-WX or equip standard units with weatherproof enclosures.
4.2 Maintenance Considerations
Dry-type transformers: No oil changes needed; only periodic cleaning (every 1–2 years).
Oil-immersed transformers: Require regular oil checks and leak monitoring, but have higher overload capacity for remote or rural use.
5. Compare Cost vs. Life Cycle Value
5.1 Initial Investment
SCB18 (Level 1 efficiency) costs 20–30% more than SCB10 (Level 3), but energy savings offset the difference over time. For low-utilization applications (<50% load), SCB10 offers better short-term value.
5.2 Lifecycle Cost
Total Cost = Purchase Price + Operating Loss Cost + Maintenance
Example: Over 10 years, an SCB18 can reduce overall cost by 15–25% compared to an SCB10 due to lower energy consumption.
Choosing a dry-type transformer is a multidimensional decision that must balance technical performance, site conditions, regulatory compliance, and total ownership cost. A scientifically selected transformer ensures power system stability, reduces operational expenditure, and supports green, low-carbon development. Users are encouraged to follow industry trends and adopt innovative products to achieve optimal performance and long-term returns.
