Collocating method of power flow controllers for DC grids

DC grid is the development direction for future power grid. Comparing with multi-terminal HVDC, DC grid has meshes and redundancies improving system flexibility and reliability greatly but also bringing new challenges for the network control. This paper analyzes the operating principle of power flow controllers for DC grid and their effects on system's power flow in detail and proposes a collocating method and principle of power flow controllers for DC grid based on operation space of power flow before and after power flow controller for DC grid and line load flow, the paper then constructs functions to judge whether the position is proper for power flow controller and takes the most balanced power flow as example to optimize the system's power flow. The paper takes a six-terminal DC grid as example to explain the configuration of DC grid power flow controller in normal operation and N-1 state and verify the correctness and effectiveness of the configuration method by the change of the power flow before and after the power flow controller. The conclusion of this paper provides theoretical foundations for configuration of the power flow controller for future DC grids.