Toward the Universal DC Distribution System

AbstractDue to an increasing number of power generation units and load devices operating with direct current (DC) at distribution level, there is a potential benefit of leading efforts toward building a DC distribution system. However, the implementation of DC distribution systems faces important challenges, including the market inertia of AC systems and standardization. Many of the benefits that are attributed to DC can only be realized if a complete DC system is developed, and not if only a few components are replaced. This paper presents the concept of a universal DC distribution system, as envisioned by the authors. The universal DC distribution system could be implemented in various use cases, but could also completely replace AC distribution grids. The paper covers the possibilities of having DC nanogrids inside buildings, DC microgrids in neighborhoods, and the connection to AC and DC medium voltage grids. Furthermore, considerations regarding flexibility, electricity market design, control, and protection are presented.