Overview on faults and protections in LVDC microgrids connected to the AC utility

摘要

Growth of distributed generation and the increasing the presence of power electronic devices and energy storage systems are provoking an increasing interest in Low Voltage DC (LVDC) microgrids. Fault protection in such systems is thus becoming more and more important. This paper provides an overview of different possible cases of fault behaviour in LVDC microgrids connected to the AC utility grid. Commonalities and differences between normal operation and fault condition are highlighted. After discussion of some existing critical issues, some possible solutions that are able to guarantee an effective and selective protection of DC microgrids and avoid damage to the power electronic converters are proposed.