Power Transformers 51 MVA and 220 kV: Modernization of a Hydroelectric Power Station

SEA SpA is proud to announce the completion of a new significant project.


We have recently manufactured two state-of-the-art three-phase oil-immersed transformers, developed specifically as part of a comprehensive renewal (2021-2025) of a hydroelectric power station in Spain: this project aims to enhance operational efficiency and increase energy production capabilities.
The hydroelectric power station uses water from two reservoirs: the first one which transports water to the power station through an open-air canal and the second one which transports water through a tunnel-type canal. It was commissioned in 1966 and consist in an outside well power station, with a waterfall of almost 50 meters and an installed capacity of 132,34 MW.
The plant currently offers three ways of hydroelectric use: one, as a generator through turbination and one as a generator through pumping reservoirs.

The two transformers are designed for a rating power of 51 MVA under standard operating conditions.
They consist of three individual units, each with a rated power of 17 MVA.
The transformer features a no-load primary voltage of 220 kV and provides four secondary outputs:

  • Three outputs, each with a voltage of 5.5 kV
  • One auxiliary output with a voltage of 15 kV

This configuration ensures that the transformers can meet the different requirements of the hydroelectric power station, supporting both its primary and auxiliary functions.
The key feature of this product is its ability to handle a substantial amount of input voltage, reflecting SEA’s established expertise: with over 60 years of experience, we have continuously refined our production processes and leveraged the latest technological improvements to deliver high-quality and reliable solutions.
This product is a demonstration of our commitment to innovation and excellence in the energy sector, thanks also to the extreme reduced losses, at no-load and load conditions.

At SEA SpA, we work to meet the evolving needs of our customers: our commitment extends to improving energy efficiency and minimizing environmental impact across all contexts where our products are used. These principles are a key aspect through our operations to reach a more sustainable future, especially during this critical phase of global energy transition.

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