Grid behavior under fault situations in ±380 V DC distribution systems

DC microgrids have become widely adapted in recent years, with 380 V being the most common voltage choice in applications like data centers and central offices around the world. For future developments with an increasing power demand, adding a second line conductor to a DC microgrid can provide means to increase overall energy efficiency. This paper evaluates fault situations in such a bipolar ±380 V DC microgrid containing only power electronic devices, thereby providing only low fault energy. Two basic grounding methods for bipolar grids and their consequences on grid safety and fault behavior are examined. Initially, exemplary fault situations are simulated. The results are then discussed and verified by setting up a test grid in the laboratory.