Towards fully controllable multi-terminal DC grids using flexible DC transmission systems

This paper develops a flexible DC transmission system (FDCTS) to power control and load flow control within the multi-terminal (MTDC) grids. The FDCTS include static power electronics-based elements for electric energy transmission inside a DC grid. Considering the current advancements in the field of power electronics, this paper proposes a cascaded power flow controller (CPFC) as the first element of the FDTCS for providing power control in MTDC grids. It is shown through dynamic simulations that the CPFC is able to control power flowing through a particular DC transmission line, and thus enhancing controllability in the MTDC grids.