Analysis of deviations on the optimal power flow operation of MTDC networks: A comparison between droop control and the DVC strategy

There is a growing interest in the development of high-voltage multi-terminal direct current (MTDC) networks for integration of renewable energy sources, reinforcement of existing ac networks and feeding remote locations. Although many studies have investigated power flow control strategies for MTDC networks, few studies have looked into the possible sources of load flow errors. The aim of this paper is to analyze the effect of errors in the OPF operation of these future HVDC grids for three different sources: voltage measurement errors;variation of cable resistance with temperature and error in the prediction of the generated power from renewable sources. To perform the analysis a direct current OPF tool is used to compare two different control strategies, namely droop control and the distributed voltage control (DVC) strategy. The OPF object function is the minimization of losses in the MTDC network, which is based on the recently built 5-terminal HVDC grid in Zhoushan, China.