Protecting the World’s Largest Hydropower Generators

UK-based surge protection manufacturer Metrosil  has completed the shipping of high energy silicon carbide varistor systems to protect China’s Three Gorges Corporation (CTG) 16GW Baihetan hydropower plant from unexpected power surges and de-excitation.

The order of Metrosil 8000 Series began delivery to the Baihetan construction site in January 2021 and will complete the supply of Metrosil varistors across the world’s five largest hydropower plants: Three Gorges and Xiluodu in China, Itaipu in Brazil and La Grande in Canada.

Metrosil 8000 Series

Once completed in 2022, Baihetan will operate the world’s largest hydropower generators at 1GW each. The capacity of the de-excitation units, which protect the generators from rapid voltage changes, will also be the highest rated in the world, at a capacity of 22 MegaJoules each for a total protection energy of 352 MJ.

Speaking about the order, Ian Rowley, Metrosil’s Product Development Manager said:

“It is with great pride that we can continue to support the development of renewable infrastructure across China’s state grid through our ongoing innovation into high-energy surge protection.

“As power projects become more ambitious, the demands on the materials and the systems that protect them increases. Through our investment in one-of-a-kind testing equipment – the High Energy Test Laboratory – we are able to help China create new operational limits for safe hydropower generation.

“With our state-of-the-art laboratory, we test the maximum rating of all our varistors before they leave the factory. This is a new level of assurance for engineers who must protect their most valuable assets from energy transients, and one that was simply not possible before.”

Surge protection is a requirement for all large power projects, including for nuclear, coal and oil. Unexpected voltage surges can cause substantial damage, rendering a generator inoperable. As power projects become larger, so too do the generators. The largest generators can weigh in excess of 4000 tonnes, and when submerged in water, can be particularly challenging and costly to repair.

Over several decades, backed by the innovation prowess of parent company M&I Materials, Metrosil has developed its surge protection capabilities to protect thousands of power plants across the world.

The High Energy Test Laboratory allows Metrosil to offer certification of its surge protection products, which gained Metrosil an accolade from world-renowned de-excitation expert Mr Li in his latest book – Design and Application of Modern Synchronous Generator Excitation Systems.