Overview of Grounding and Configuration Options for Meshed HVDC Grids

This paper provides an overview and comparison of the possible grounding and configuration options for meshed HVDC grids. HVDC grids are expected to play a key role in the development of future power systems. Nevertheless, the type of grounding and the base configuration for the grid have not yet been determined. Various studies related to multiterminal HVDC or meshed HVDC grids often assume one specific configuration and grounding scheme and take it for granted. However, since a large number of options exist, an overview is needed to balance the pros and cons. In this paper, the influence of the different grounding options on fault behavior is investigated for point-to-point connections. Furthermore, the impact of the grounding type on the system fault behavior is investigated with electromagnetic transient simulations. Next, the suitability of a configuration to serve as a base configuration in a meshed dc grid is investigated and compared in terms of extensibility and flexibility. In this evaluation, the grounding type, the number, and location of grounding points in a grid are considered as well. Finally, an overview of the most important conclusions is given in a summarizing table.