When a short-circuit fault happens in a DC microgrid

the characteristic values of every fault are similar to each other

thus current protection arithmetic can not distinguish a fault from others.We analyzed the fault current of a DC microgrid with multiple buses

and proposed a new fault classification method

in which some inductive impedances in the microgrid was installed and the fault current and current derivative were combined.The inductive impedances which were installed in every line of the DC microgrid could make a great variation to the fault current and its derivative under the fault transient condition

thus the protection unit could classify the faults into three types including bus fault

interconnected line fault

and adjacent bus（or line） fault.The simulation testing results prove that the protection based on the new fault classification method can accurately identify each fault type happened in microgrid

exactly isolate the fault area and quickly restore the power system

and it is an effective protection scheme which is suitable to short-circuit faults happened in a DC microgrid with multiple buses and lines.