What is a dry-type transformer? Advantages, applications and selection guide

In contemporary power systems, dry-type transformers are extensively applied in industrial, commercial and civilian power systems because of their safety, environmental protection and low maintenance costs. Dry-type transformers are less likely to use insulating oil compared with oil-immersed transformers, avoiding the risk of fire and environmental pollution, thus becoming a suitable option for most application scenarios.

What is a dry-type transformer?

Dry-type transformer is used for a transformer that does not use liquid medium cooling. It has air or other solid insulating materials to cool and insulate its windings and core. Common insulating materials are epoxy resin, glass fiber and silicone rubber.

As for insulation techniques, dry-type transformers can be categorized mainly into the following two types:

Cast dry-type transformers (epoxy resin casting) – dust-proof and moisture-proof, excellent short-circuit strength, and can be used indoors.

Open dry-type transformers (H-class or F-class insulation) – glass fiber reinforcement and insulating paint, excellent heat dissipation.

Dry-type transformer advantages

① Safe and reliable
Oil-free dry-type transformers are neither safety hazards such as oil leakage and fire, nor can they be applied to fields with high safety levels, such as hospitals, shopping malls, underground construction, etc.

② Green and environmental protection
It does not employ insulating oil, neither does it create pollution nor has toxic gas emission. It meets the existing needs of energy conservation and environmental protection and is particularly suitable for use in clean energy applications such as urban power distribution and wind energy generation.

③ Low maintenance cost
Since solid insulation materials are employed, dry-type transformers exhibit good corrosion resistance and moisture and have easy everyday maintenance and 20-30 years’ long service life.

④ Low operation noise
By the use of high-quality silicon steel plates and fresh winding structures, dry-type transformers have low operation noise and can be used in noisy-sensitive places such as residential districts, office buildings, and commercial complexes.

⑤ Powerful overload capacity
Dry-type transformers utilize forced air cooling or natural air cooling for heat dissipation and have good short-term overload ability. They are suitable for industrial applications with large load fluctuations, such as steel, chemical and other industries.

Application fields of dry-type transformers

✅ Building power supply: for instance, high-rise buildings, airports, subway stations, shopping malls, etc., to ensure safe and stable power supply.
✅ Industrial manufacturing: can be used in steel, petrochemical, pharmaceutical and other industries, and can withstand harsh environments.
✅ Data center: Provide stable and efficient power supply for server rooms.
✅ New energy field: wind power generation, photovoltaic power generation, etc., can be wired with inverters.
✅ Rail transit: used in station power supply and traction substations of subway, high-speed rail and other projects.

How to choose a proper dry-type transformer?

When purchasing a dry-type transformer, the following factors should be considered:
✔ Capacity: Determine the capacity of the transformer required according to the load power, for instance, the popular 100kVA, 250kVA, 500kVA, etc.
✔ Voltage level: Common input voltages are 10kV, 35kV, and the output voltages are 400V, etc.
✔ Environmental conditions: If they work in a humid, high-temperature or dusty environment, the corresponding protection level should be selected.
✔ Energy efficiency rating: Choose energy-efficient transformers with national standards to reduce long-term operating costs.

Conclusion

Dry-type transformers have an important role to play in the power system due to their safety, eco-friendliness, and minimal maintenance. Under city power supply, industrial manufacture, or application for new energy, dry-type transformers are an optimal choice. At the purchase step, qualified products that satisfy the IEC and CE certifications need to be chosen to ensure operational stability and security.

If you have question about purchase or selection of dry-type transformer, please call TRONKI Electric, we will provide the professional solutions!