Siemens has installed a fourth offshore platform in the North Sea, completing an important stage for grid connections of sea-based wind farms. This is the platform for the SylWin1 DC link, which is the most powerful of the four offshore wind power grid connections contracted to Siemens by the German-Dutch transmission grid operator TenneT between 2010 and 2011. The fifth grid connection, which was contracted earlier this year, is slated to go on-line in 2019.
World’s largest converter platform
The newly installed SylWin1 platform with a capacity of 864 megawatts (MW) and located 70 km to the west of the North Frisian island of Sylt, after which the project was named, will concentrate the wind power produced by the three North Sea wind farms Dan Tysk, Butendiek and Sandbank and transmit the electricity to land. This platform, with dimensions of 83 × 56 × 26 meters (length x width x height) is the largest converter platform installed to date world-wide. With its baseframe, the platform has a total weight of 25,000 tons. After start of commercial operation in 2015, it will supply 900,000 German households with emission-free wind power.
Hardly any energy loss at long-distance transmission
Using the Siemens technology installed on the platforms, the alternating current power generated by the wind turbines is transformed into direct current for efficient transmission onto land. At the associated land-based station the electricity from the linked wind farms will be converted back into the alternating current power required for feeding into the grid. Thanks to the low-loss high-voltage direct-current (HVDC) technology used here, transmission losses are less than four per cent.
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