The dry evolution

Dry-type transformer - Responding to a changing world

A dry-type transformer is essentially one that has no oil, which eliminates risk of oil leakages (ecologically friendly), and fire hazards. Safety is one of the fundamental drivers in the design of dry transformers because they are often installed in places with high people density, such as airports, sports stadiums, hospitals, shopping centers, skyscrapers, factories, power and industrial plants. Here the risk of fire is a prime concern, because even a minor failure can be disastrous in terms of loss of life and environmental damage.

The development of oil-free or dry-type transformer technology as it is often referred to, picked up in the 1970s to cover the need for higher safety standards for people, property and the environment. Over time they have evolved into broadly two categories or product families, each reflecting specific needs.

Standard dry transformers are deployed to safely distribute electricity to end users, and can be manufactured using different coil technologies based on applications. They address key characteristics like well-protected windings, high-efficiency cooling, or suitability for extreme climatic conditions that helps them deliver high quality performance.

In response to market requirements, special dry-type transformers have also developed in recent years to help make electricity supply systems not only more efficient and reliable, but also environmentally friendly and safe.

This green portfolio is playing an increasing role in transmission and distribution (T&D) systems, addressing an important need for safe and environmentally-friendly power products for a variety of applications, including urban settings and sensitive areas. Dry-type transformers can now be used in some applications for the very first time, thanks to innovations that increase energy efficiency and make higher voltages possible in compact outdoor and submersible installations.

These high-voltage and power capacities (up to insulation class levels F or H, for example) also come in a triangular rather than standard construction. The focus on energy efficiency enables special dry products to better serve market segments like wind power, marine, traction systems and variable speed drives (VSD).

There has been a sea change in cultural attitudes since the 1970s. Safety and now the ideas of safety and respect for the environment are not just considered “advantages” any more, but essential product features. It is a new way of doing things that will help us preserve the planet not only for ourselves, but for our children and our children’s children.

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About the author

Mariano Berrogain

I am the Global Product Manager for new dry products, responsible for business development of dry transformers worldwide. I am based in Spain, and I have worked at ABB for 16 years in various roles including transformers engineering, project management and sales.
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