Parallelling offshore wind farm HVDC ties on offshore side

In some regions where wind farms are connected to the main grid through HVDC links, the parallelling of these links on the offshore ac side has been advocated or even required. Such parallelling implies the creation of an ac island which is far from resembling a typical ac system. Mainly because of: A) Wind turbine driven generators are not normally of synchronous type. B) The “loads” offshore will consist of HVDC links transporting the power to the mainland, and these links are entirely different from normal loads; mainly because the control system will regulate them. C) The offshore network will mainly consist of rather short cables. Compared with transmission lines, they have much higher shunt susceptance (capacitance) and lower losses.