HVDC Transmission of Offshore Wind Farm Using Current-Source Actively Commutated Converter With Very-Low-Capacity AC Network

The existing HVDC transmission technologies for offshore wind farm is summarized and analyzed first. Based on these analyses, this paper presents a current-source actively commutated converter (ACC) based HVDC transmission system for offshore wind farm. This system employs fundamental switching frequency ACC for HVDC transmission with very-low-capacity AC network as the startup and auxiliary power supply for the wind farm. The operation principle of this system is analyzed and the startup and steady-state control strategy of this system is also proposed. Comparative analyses with the existing VSCHVDC solution show obvious advantages of the technology in this paper in terms of passive component requirement, DC side fault suppression capability and so forth. Simulation results of a ± 250kV/1000 MW ACC based wind farm HVDC system verified the proposed system with the control methods.