Power Flow Control and Mode-Switching Method Considering Single-Pole Trip for Bipolar MTDC System

Due to the advantage of the system operation reliability and flexibility, the bipolar multi-terminal high voltage dc (MTDC) transmission has attracted worldwide attention for the integration of offshore windfarms. However, majority of existing operation methods and dc power flow algorithms are designed to control the monopolar MTDC system. It is difficult to implement the conventional control method for the monopolar system into the bipolar system due to the difference in the characteristics of dc power flow control scheme between the two configurations. Therefore, this paper proposes an operation method of the bipolar MTDC system composed of the dc power flow control scheme and mode-switching method. As a simulation result, the proposed method can realize the power sharing between each VSC and reduce the impact of the active power fluctuation on the AC grid connected to the system even when the single-pole trip occurs in the bipolar MTDC system.