Comparison of DC voltage Control Strategies for Multi-terminal HVDC Network during AC Faults

Multi-terminal HVDC grid is one of the promising solutions of the electrical power network configuration that ensures the reliability of power supply and economy of the power generated from numerous renewable sources. The benefits of using HVDC grids are the possibilities of trading energy in different AC systems and transporting large scale of power over long distances. This paper will be showing the importance of DC voltage control strategies in a multi-terminal VSC-HDVC system following a system disturbance caused by an asymmetrical three-phase fault. Conventional and Droop methods are the two control strategies that will be compared in this paper. MATLAB/Simulink software simulator will be used to evaluate the response of a DC grid when a three-phase to ground AC fault occurs. The results show that droop-controlled DC grids are highly reliable during abnormal operating conditions compared to the conventional method.