Thialf Installs World's Highest-Voltage Offshore Converter Station

Thialf, the world’s largest crane vessel was recently put to work in the North Sea by Swiss power and automation group, ABB, to install the world’s highest-voltage offshore converter station.

In a three-day operation, the 9,300 metric ton topsides module, including the converter station, was transported offshore by barge around 75 km off the German coast. It was then lifted by the Thialf and positioned on top of the installed jacket.

This converter station will be fed by AC power generated from three wind farms off the coast of Germany, then converted into high voltage DC for transmission to shore.

This 320 kilovolts converter station has an 800 megawatt power transmission capacity making it the world’s most powerful installation of its kind.

Images (c) ABB

“Putting such a huge platform in place is one of the most delicate operations in the delivery of an offshore transmission link, requiring strong cooperation between the many stakeholders involved” said Brice Koch, Head of ABB’s Power Systems division. “This is an important project milestone in the delivery of this HVDC offshore wind connection and we are pleased it went smoothly.”

ABB was awarded the turnkey responsibility for system engineering, design, supply and installation of the offshore wind connection by TenneT, a leading European transmission system operator. The project scope includes the offshore converter station, the sea and land cable systems, and the onshore converter station.The system features the latest generation of ABB power semiconductors, with increased performance that ensures higher availability and lower losses.

ABB notes the energy transmitted from the DolWin 1 offshore wind connection is expected to reduce Germany’s yearly CO2 footprint by 3 million tons.