What Are the Similarities and Differences Between Epoxy Resin Cast Dry-Type Transformers and Impregnated Dry-Type Transformers?

Dry-type transformers are cooled and insulated by air or other solid insulating materials instead of using liquid coolants. The two main types of dry-type transformers globally are epoxy resin cast and impregnated transformers. Below is a comprehensive comparison of their performance.

Content

●Short-Circuit Withstand Capability

Epoxy resin cast transformers have superior short-circuit withstand capability. The windings of these transformers are cast as a whole in a mold and then heat-cured to form a high-strength cylindrical structure. This design provides extremely high radial and axial mechanical strength, allowing the transformer to withstand the immense mechanical stress generated during short circuits, ensuring safe operation under extreme conditions.

●Heat Dissipation Performance

Epoxy resin cast dry-type transformers also have better heat dissipation performance. Their layered winding design allows for multiple cooling ducts to be set along the axial direction of the windings. These ducts enable efficient airflow, greatly enhancing heat dissipation and ensuring the transformer maintains an appropriate temperature even under high load. In contrast, impregnated dry-type transformers often use a pancake coil design, which has poorer ventilation performance. This design restricts airflow, resulting in lower heat dissipation efficiency and a higher risk of overheating.

●Environmental Adaptability

Epoxy resin cast dry-type transformers excel in moisture resistance and corrosion resistance. Their structure effectively prevents moisture and corrosive substances from penetrating, making them especially suitable for harsh environments such as high humidity or high pollution areas. The main drawback of traditional impregnated dry-type transformers is their poor moisture resistance, making them prone to dust absorption. Although modern impregnated transformers use NOMEX paper and vacuum pressure impregnation techniques to improve these issues, their moisture and corrosion resistance still do not match that of epoxy resin cast transformers.

●Environmental Friendliness

Both epoxy resin and NOMEX paper are organic materials that do not degrade naturally. Therefore, both types of dry-type transformers face challenges regarding degradation and recycling at the end of their service life. However, neither material pollutes the environment during production, and they can be recycled in a controlled factory environment. Notably, there is extensive experience in Europe for recycling and processing epoxy resin cast dry-type transformers, providing reliable environmental protection.

In Summary

Epoxy resin cast dry-type transformers perform better in short-circuit withstand capability, heat dissipation, and environmental adaptability, making them suitable for applications requiring high heat dissipation and harsh environments. While impregnated dry-type transformers may not match epoxy resin cast types in heat dissipation, they are more cost-effective, making them suitable for budget-constrained situations. When choosing a transformer, it is essential to consider both performance and cost based on specific application requirements to achieve optimal results.

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LuShan, est.1975, is a Chinese professional manufacturer specializing in power transformers and reactors for 49 years. Leading products are single phase and three phase isolation transformers, electrical transformer, distribution transformer, step down and step up transformer, low voltage transformer, high voltage transformer, control transformer, toroidal transformer, R-core transformer; DC inductors, AC reactors, line and load reactor, chokes, filtering reactor, and intermediate, high-frequency products. Our power transformers and reactors are widely used in 10 application areas: rapid transit, construction machinery, renewable energy, intelligent manufacturing, medical equipment, coal mine explosion prevention , excitation system, vacuum sintering(furnace), central air conditioning.

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