Second North Sea platform linking up offshore wind farms installed
SIEMENS – Nordic Yards has constructed the topside for BorWin2 in its Warnemünde shipyard as a one-off job tailor-made for Siemens.
Once it goes on line, BorWin2’s output of 800 MW will provide wind power for 800,000 households on the mainland.
The offshore platform is 51 meters wide, 72 meters long and 25 meters high – and if the two permanently installed cranes are counted, the overall height adds up to 40 meters. Weighing almost 12,000 tons, the giant steel structure has been designed to spend the next 30 years on rough seas.
During that time, the material will be exposed to extreme conditions, especially in winter when the spray on the surface freezes to ice, which makes particularly tough demands of the paintwork and the anti-corrosion coating. The photo shows the platform as built, before the anti-corrosion coating was applied. 28 months have passed from the start of work to leaving the dock; the final touches will be made to the HVDC platform at sea.
The cable route runs through the Lower Saxon Wadden Sea National Park, which was designated a UNESCO World Heritage Site in 2009. To protect the flora and fauna, strict rules apply in this nature preservation area: for instance, the cables had to be laid within a certain time window and using special equipment to minimize nuisance and impact.
The converter tower for Diele has undergone advance high-voltage shop testing in Siemens’ own test bed in Dresden to verify the resistance of the insulation. The converter technology has been installed both in the onshore station and offshore on the platform. HVDC Plus technology is used on the platform to convert the alternating current generated by the wind farms into low-loss direct current. This is then transported to the mainland via a submarine cable, with a total loss of less than four percent.
The heart of the BorWin 2 grid connection is the BorWin beta offshore converter platform, which houses the Siemens system for high-voltage direct current (HVDC) transmission. Successfully installing this system on the high seas was the most critical part of the project.
Apart from constructing and installing the offshore platform itself, which transforms the alternating current generated into direct current for low-loss transmission, a submarine cable had to be laid and a converter station set up on the mainland. That is where the power delivered from the offshore generating installations is converted into alternating current for feed into the national grid. more> http://tinyurl.com/ljkzbds