DC voltage control and power dispatch of a multi-terminal HVDC system for integrating large offshore wind farms

Multi-terminal HVDC transmission technology using voltage source converters is proposed for integrating large offshore wind farms with transmission grids. Different DC voltage control and power dispatch strategies are proposed to demonstrate the flexibility and capability of such a transmission system in integrating large-scale variable wind generation. Various options for ensuring satisfactory ride through onshore grid faults are discussed. PSCAD/EMTDC simulations on a four-terminal high voltage direct current (HVDC) system with two offshore and two onshore converter stations during wind speed and power variations, and control mode switching are presented to show the robust performance and ability of the proposed system. Further studies during severe fault on one of the connected onshore AC networks are provided to validate the fault ride through capability of the multi-terminal HVDC system.