HelWin1: Grid connection of Offshore Wind Farms

Prysmian has been awarded a project worth in excess of € 150 million by the German transmission system operator transpower - a subsidiary of the Dutch grid operator TenneT - for the grid connection project HelWin1 linking two offshore wind farms in the North Sea to mainland Germany.

Prysmian will provide complete supply, installation and commissioning of the submarine and land cable connections as part of a larger contract worth approximately a half billion, awarded to the consortium of Prysmian and Siemens Energy. Siemens will deliver the Voltage Sourced Converter (VSC) system, with a rating of 576 MW. The turnkey connection will first link the Offshore Wind Park Nord See Ost, located about 85 km offshore, to the mainland with the purpose of transmitting wind generated renewable power into the German Grid.

The project closely follows the recently awarded BorWin2 project, worth more than € 200 million, which sets a number of milestones in the industry as it will be the first commercial ± 300 kV DC cable project using extruded technology (highest direct current voltage level ever reached), the first 800 MW connection to offshore wind parks and the largest VSC system with a capacity of 800 MW. The HelWin1 project will also use extruded HVDC cable technology from Prysmian together with Siemens HVDC Plus® converter technology at the offshore platform and onshore stations. The HVDC connection of approximately 130 km to be supplied by Prysmian will comprise subsea and land cable types at a voltage of ± 250 kV DC along a 85 km sea route passing to the east of Helgoland continuing along a 45 km land route to the land converter station in Büttel, north-west of Hamburg. Extruded 155 kV HVAC submarine cable connections will complete the connections from the offshore wind park transformer platforms to the offshore converter platform.

The cables and accessories will be manufactured from 2011 onwards in Prysmian’s European HV factories including the dedicated submarine cable facility in Arco Felice, Italy. Installation activities will commence in 2011 and continue throughout 2012. The commencement of operation of the HVDC link is planned for 2013.