Because　of　the　hazard　of　single-phase-to-ground　faults　on　distribution　networks　for　human　security　and　device　insulation,　it　is　important　for　the　ground-fault　current　to　be　eliminated　by　an　arc-suppression　device.　However,　owing　to　their　shortcomings,　passive　arc-suppression　devices　cannot　compensate　the　ground-fault　current　fully.　Therefore,　active　arc-suppression　devices　have　been　studied.　The　flexible　arc-suppression　device　(FASD)　with　a　cascaded　H-bridge　(HB)　topology　is　one　type　of　active　arc-suppression　device.　An　FASD　connected　to　a　bus　bar　of　distribution　networks　is　applied　to　mitigate　the　ground-fault　current.　Owing　to　the　high　voltage　and　large　current　during　the　ground　fault,　a　large　number　of　HBs　are　required　for　the　FASD.　To　modulate　the　HBs,　an　improved　distributed　commutations　modulation　method,　which　is　combined　with　the　flexible　arc-suppression　method,　is　proposed.　The　proposed　modulation　strategy　aims　to　minimise　the　error　between　the　reference　signal　and　the　tracking　signal　during　each　sampling　period.　Finally,　the　proposed　strategy　is　validated　via　simulations　and　experiments　to　confirm　its　effectiveness　for　the　FASD.