Traditional　arc-suppression　devices　have　a　weak　effect　on　the　arc-extinguishing　result　of　earth　fault　because　of　increased　active　and　harmonic　components　of　fault　current.　To　solve　the　problem,　in　this　paper,　a　flexible　arc-suppression　device　based　on　a　three-phase　cascaded　H-bridge　(CHB)　converter　with　auxiliary　sources　is　further　developed;　on　this　basis,　an　arc-suppression　method　based　on　the　improved　finite　control　set　model　predictive　control　is　proposed.　The　proposed　approach,　which　uses　a　combination　of　two　voltage　levels　in　a　sampling　period　to　reduce　the　steady-state　current　error,　controls　the　CHB　converter　to　inject　compensation　current　into　the　distribution　network.　Taking　into　account　the　reduction　of　switching　losses　and　balancing　heat　in　each　H-bridge　cell,　a　novel　method　that　causes　the　switching　transitions　to　be　distributed　evenly　among　the　H-bridge　cells　is　proposed　to　select　the　optimal　switching　combination.　The　tracking　capability　of　the　improved　control　method　is　analyzed,　and　the　parameters　affecting　the　arc-suppression　performance　are　obtained.　The　simulation　and　experimental　results　show　that　the　proposed　method　achieves　an　excellent　performance　of　suppressing　fault　current　and　extinguishing　arc.　Moreover,　the　balance　of　switching　transitions　is　also　achieved.