HV multi-terminal DC lines as the backbone of the energy transmission system – A research plan to tackle challenges

Transmission system reinforcement is an issue of great importance, in an effort to handle the increasing renewable power generation. Nevertheless, the upgrade of the transmission system (lines, substations, etc.) is not always attainable, due to techno-economical restrictions. To this context, High Voltage Direct Current (HVDC) grids or converting already existing AC lines to DC lines could offer an alternative solution, considering also the interconnection of offshore intermittent renewable generation resources, the connection of remote generation sources to load centers and the inter-continental transfer of large quantities of energy surpassingly an overlay grid. The current work presents a research plan for multi- terminal HVDC grids, in an effort to face technical challenges.