Technology developments and plans to solve operational challenges facilitating the HVDC offshore grid

This paper describes voltage source converter (VSC) offshore technologies for expansion of point-to-point transmission systems to HVDC offshore grids. Today several gigawatt wind farm projects are underway or have been proposed in the North Sea, Baltic Sea and Atlantic Ocean. These first offshore VSC stations has been installed on oil and gas platforms for power from shore in 2005 or using structures that are lifted on site for connection of wind farms in 2010. New and innovative modular solutions for converter offshore platforms in the gigawatt-range have been developed. As the offshore wind generation increases it makes sense to connect the offshore converters into a multi-terminal grid for better utilization of the transmission systems and connection to balancing power. The key technological cornerstones to plan and start building the first parts of HVDC offshore grids are available today and the gaps for deployment of a full-fledged offshore grid are outlined.