Study on DC arc faults in ring-bus DC microgrids with constant power loads

DC microgrid offers significant advantages such as control simplicity and less conversion stages for energy storage, renewables and electronic load integration. However, its implementation is highly restricted by the development of dc protection system. Especially, the series dc arc faults have been posing significant challenges due to low fault current level. This paper explores the impact of dc arc fault in dc microgrids with constant power loads (CPLs). An effective power flow and dc arc modeling method is presented, based on which the dc arc fault responses at different locations are analyzed. It is concluded that with a ring bus structure and droop control, the microgrid is naturally resistant to series dc arc fault at the source and dc buses. However, arc fault by the load side can still cause serious damages. Based on the fault responses study, dc arc detection and protection considerations are discussed.