The　residual　fault　current　of　active　voltage-based　arc　suppression　(AVAS)　method　is　affected　easily　by　the　load　current　in　case　of　low-resistance　ground　(LRG)　fault,　and　the　active　current-based　arc　suppression　(ACAS)　method　is　difficult　to　suppress　the　fault　phase　recovery　voltage　effectively　in　case　of　high-resistance　ground　(HRG)　fault.　In　both　cases,　the　single-phase-to-ground　(SPG)　fault　arc　cannot　be　expressed　reliably,　leading　to　the　expansion　of　accidents.　An　active　optimization　arc　suppression　(AOAS)　method　is　proposed　to　address　the　problems.　The　ACAS　method　that　is　less　affected　by　load　current　can　be　used　for　LRG　fault,　and　the　AVAS　method　that　can　suppress　the　fault　phase　recovery　voltage　effectively　can　be　used　for　HRG　fault.　The　cascaded　H-bridge　converter　(CHB)　is　used　to　inject　current　into　the　neutral-point　of　distribution　networks　for　fault　resistance　estimation　and　arc　suppression.　At　the　beginning　of　a　SPG　fault,　the　CHB　converter　injects　an　interharmonic　current　into　the　distribution　networks　to　estimate　the　fault　resistance　as　a　switching　threshold　of　the　two　arc　suppression　methods.　The　simulation　indicates　that　the　proposed　AOAS　method　is　more　adaptable　for　the　change　of　SPG　fault　conditions　and　can　optimize　the　effect　of　arc　suppression.　©　2021　IEEE