ABB installs world’s most powerful offshore HVDC converter station
An offshore platform that will collect power from wind turbines in the North Sea and feed it into the German grid has successfully been installed by the world’s largest crane vessel, said in the company's press release.
Weighing more than 16,000 metric tonnes (the topsides being 9,300 tonnes), the platform is one of the main components in a grid connection project called DolWin1. The technology on the platform will convert alternating current (AC) from three wind farms into high-voltage direct current (HVDC) so that the electricity can be distributed with minimal losses and without disrupting the grid.
ABB was awarded the turnkey responsibility for system engineering, design, supply and installation of the Dolwin 1 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.
The platform – which is 62 meters long, 42 meters wide and 42 meters high – was transported by barge from Schiedam (near Rotterdam) to its destination 75 km off the East Frisian coast. The topsides built by Heerema Fabrication Group (HFG) at the Dutch Zwijndrecht fabrication yard, were then lifted by the world's largest crane vessel, Thialf, and positioned on top of an already installed jacket (the steel substructure). The lifting and placement operation was the most challenging part of the three-day operation.
“The successful installation of the offshore station is an important milestone in the construction of our HVDC offshore wind connection, which will ensure efficient transmission of renewable energy to the onshore grid in Germany,” said Hanspeter Faessler, Head of Grid Systems business at ABB, which is responsible for the construction of the platform and installation of the electro-technical equipment. The jacket and topside platform have been welded together and will now be connected to the subsea cables prior to commissioning.
The technology on the platform will convert the electricity from the wind farms into direct current. The power will then be transported via 75 km of HVDC sea cables and 90 km of HVDC land cables to a converter station onshore, where it will be converted back into alternating current so that it can be fed into the grid. The power transmission line has a capacity of 800 megawatts.
ABB is using HVDC Light, an evolution of HVDC technology that helps address the needs of long-distance underground and subsea transmission. It is increasingly being deployed across a range of applications including integration of renewable energies from land-based and offshore wind farms, mainland power supply to islands and offshore oil and gas platforms, city center in-feeds where space is a major constraint, and interconnections, often across the seas. ABB leads the way in this space, and has delivered 13 of the 14 commissioned HVDC links based on VSC technology.