A　three-phase　cascaded　H-bridge　converter　(CHC)　without　DC　sources　can　be　employed　to　suppress　single-phase　ground　(SPG)　fault　arc　via　a　Y-connection　in　active　distribution　networks.　Nevertheless,　its　DC　voltage　maintenance　methods　lead　to　an　error　in　its　output　zero-sequence　current,　which　causes　arc　suppression　failure　in　practice　and　requires　a　large　power　of　the　CHC.　This　paper　proposes　a　novel　implementation　method　for　the　Y-type　CHC　to　improve　fault　arc　suppression　capability　and　minimize　required　output　power.　In　this　method,　one　CHC　arm　connected　to　the　ground　is　controlled　as　a　voltage　source,　and　its　output　voltage　vector　is　perpendicular　to　the　reference　vector　of　the　zero-sequence　current　required　for　arc　suppression.　The　other　two　CHC　arms　connected　to　the　two　non-faulty　phases　of　distribution　networks　are　controlled　as　current　sources,　and　their　output　current　vectors　are　perpendicular　to　the　voltages　across　them,　and　the　sum　of　their　output　current　vectors　is　equal　to　the　reference　vector　of　the　zero-sequence　current　required　for　arc　suppression.　Thereby,　the　three　CHC　arms　only　output　reactive　power,　thus　maintaining　their　DC　sources,　and　the　total　output　zero-sequence　current　error　is　eliminated.　Finally,　the　output　voltage　amplitude　of　the　voltage　source　is　calculated　to　minimize　the　total　output　power　of　the　three　arms.　The　simulation　and　experimental　validation　demonstrate　that　the　proposed　method　enhances　the　fault　current　and　fault　voltage　suppression　rate　and　minimizes　the　required　power　of　Y-type　CHC.　©　2013　IEEE.