Power Quality Issues at the Grid Connection Point of HVDC Connected Offshore Wind Farms and Their Influence on the Production

The installed capacity of offshore wind turbines in Germany has significantly increased in the last years. Many of the offshore wind farms have a considerable distance to shore. Large-scale HVDC converters connect wind farm clusters to the public grid. The synthetic offshore AC grid, with its inherent properties, provides a number of challenges for the wind farm operators. One of the main risks for them is the quality of the grid connection provided by the transmission system operator. Dynamic influences of the transmission system or neighboring wind farms originate power quality disturbances and may seriously affect the production of a wind farm. The aim of this paper is to investigate the power quality in the offshore grid in general and its influences on the production of the wind farm.