Siemens Consortium Wins EUR500m Order To Link Offshore Wind Farms

A consortium of Siemens Energy and Prysmian Powerlink has received an order worth more than EUR500m from German transmission grid company Transpower, a subsidiary of TenneT, to connect two North Sea offshore wind farms to the transmission grid.

The Veja Mate and Global Tech 1 offshore wind farms, which will have a combined power generating capacity of as much as 800MW, will be connected to the grid via a submarine cable link carrying high-voltage direct current.

Siemens will supply a voltage sourced converter (VSC) system using its HVDC Plus technology with a rating of 800MW. The converter will be installed on an offshore platform, where the voltage level will be stepped up from 155kV to 300kV alternating current (AC) and then converted to direct current (DC) at the same voltage level.

The platform will accommodate all the requisite electrical equipment for the HVDC converter, primarily the converter itself, two transformers, four AC cable compensation reactors and high-voltage gas-insulated switchgear.

The Siemens Wind Power Offshore Substation (WIPOS) will be designed as a floating, self-lifting platform. This platform will be towed by tugs to its destination at sea, where the water is about 40mt deep, Siemens said.

The wind power will be transported via submarine and land cable to Diele near Papenburg, where an onshore substation will reconvert it from DC to AC for further transmission and distribution within the 400kV AC grid.

The design and engineering phase for the BorWin 2 offshore grid connection will be completed by mid-2011. The onshore substation will be built in 2011, with installation of the offshore platform planned for mid-2012. Cable laying is scheduled for completion in 2012. The whole transmission link is expected to begin operation in 2013.