A Review of Medium-Voltage Direct Current Distribution Technologies at ARPA-E

This paper provides a retrospective of the BREAKERS and CABLES projects related to the protection, coordination, and hardware realization of medium-voltage direct current technologies at the Advanced Research Projects Agency–Energy (ARPA-E) of the U.S. Department of Energy. These projects were funded to enable transformative advances in direct current (DC) medium-voltage (MV) microgrids and distribution systems. To do this they focus on rapid fault current identification and interruption as well as novel distribution of electrical power through lightweight medium-voltage cable systems free from damaging partial discharge. The paper includes a discussion of ARPA-E problem framing and the goals of transformative research, discussions on projects that make use of key enabling technologies such as wide bandgap semiconductors, optimal design procedures, and novel insulating and cooling methods that were developed for DC protection systems, cables, and connectors in these projects. A comparative analysis of with publicly available information for CABLES projects with commercial state-of-the-art technologies is included to provide context for the progress made to date. Finally, the distinct pathways that these technologies are taking to transition to the market are discussed.