DC-side fault current management in extended multiterminal-HVDC-grids

The global need for reliable and efficient energy supplies and the necessary shift from fossil fuels to regenerative sources imposes great challenges for improved electric power transmission. Extended HVDC-SuperGrids, covering large areas and distances, are considered to lead to very attractive solutions. While recent progress of power electronics has enabled suitable and extremely efficient converters, the best structure of a large DC-grid and the remaining other key components are still under investigation. This paper focuses on main problems, especially handling of fault currents or DC-short circuits in the grid. The interaction of the key components - Modular Multilevel Converters and DC-circuit breakers - is investigated.