The DC grid must undergo a reliability evaluation process before going into production. This paper proposes the reliability models of components including AC-DC converter and DC-DC converter. The state enumeration method as well as the optimal load curtailment(OLC) model are used to evaluate the reliability of AC-DC hybrid grid. Meanwhile, this paper compares the results of the state enumeration method and the Monte Carlo(MC) method and finds out the key components that affect the hybrid grid’s reliability. According to the results, the reliability of the AC-DC hybrid grid is lower than that of the traditional AC grid and the two components affecting the whole grid’s reliability most are IGBT and capacitor.

AC-DC hybrid system,converter,optimal load curtailment(OLC),reliability evaluation,state enumeration