Transforming the future of urban power: safe, reliable and dry

Dry-type transformers make our electricity supply systems more efficient, reliable, safe and environmentally friendly – making them ideal for densely packed cities

The explosive growth of urban centers means more than 400 cities now have populations exceeding one million people, while more than 10 million people populate each of the world`s 19 megacities: Tokyo tops the list with 37.2 million, followed by Delhi (22.6 million), then Mexico City, New York-Newark and Shanghai (each slightly over 20 million).

Dry-type transformers provide safe, reliable, oil-free power transformation, removing the risk of leaks and spills contaminating sensitive areas. ABB began developing dry-type transformers for medium-voltage applications in the 1970s, recognizing that oil-free technologies can help transformers comply with the highest safety standards for people, property and the environment. Dry-type transformers also enable electrical substations to be installed in commercial or industrial buildings without undue concern about fire risk.

Easy to install and maintenance free, they are a huge advantage in urban areas where real estate is of a premium.  Whatever the design – impregnated, vacuum cast or Resibloc – dry-type transformer technology brings many advantages:

1. Flexibility. State-of-the-art insulation material means designers can build very compact and efficient dry-type transformers in a variety of configurations.

2. Safety. Dry-type units can be installed in buildings near people, as they contain only limited combustible material, mitigating the risk of fire. They are also good for environmently sensitive areas, since there is no risk of leaking oil.

3. Easy installation. Dry-type units optimize the layout of electrical systems by reducing cable costs (since transformers are closer to consumers, less cable is needed), and also electrical losses in cables and terminals on the low-voltage side. Some units can be installed underground in vaults or subways which can get flooded with water.

4. Protection. Dry-type transformers can be enclosed to protect people against electrical exposure and the units from hazardous environments. This can significantly reduce a unit`s weight and size, making it invaluable wherever footprint is a key driver, such as ships, highrise buildings and off-shore platforms.

5. Innovations.The dry-type transformer has been around for more than half a century. New developments have increased power and voltage levels (up to  63 megavolt amperes (MVA) and  72.5 kilovolts (kV), while electrical losses have been reduced with innovations like amorphous steel and optimized coil designs, and footprint further optimized with triangular core designs.

The UN expects urbanization to accelerate in the decades ahead, doubling the number of megacities by 2025. But enormous cities require huge amounts of power to operate. The power density in areas tightly packed with skyscrapers and workplaces is very high, requiring new solutions that will safely and reliably move large amounts of electricity into our city centers. Clearly, safe, reliable and environmentally friendlier dry-type transformers will play a key role in this endeavor.

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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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