DC microgrid grounding strategies

Abstract

Grounding strategy of a DC microgrid affects the stray current level, the common-mode voltage, the energy supply reliability, personnel/equipment safety and protection system design. Therefore, a comprehensive knowledge of the available grounding strategies and their effects is essential for design and operation of the DC microgrid components and especially its protection. This paper investigates and compares characteristics of different DC microgrid grounding strategies that involve the choice of grounding configurations and grounding devices. The study includes the grounding strategy impacts on line-to-ground (LG) fault detection and protection, transient LG fault current magnitude, stray current level, common mode voltage, personnel/equipment safety, system reliability, service continuity, and insulation requirements. Finally, the strengths and weaknesses of the various grounding strategies are discussed.