The　phase-to-ground　admittance　in　distribution　networks　is　asymmetric.　This　asymmetry　is　aggravated　by　the　arc　suppression　coil,　resulting　in　zero-sequence　overvoltage.　The　magnitude　of　zero-sequence　overvoltage　can　exceed　the　line-to-ground　voltage,　endangering　the　operation　of　electrical　equipment.　Moreover,　after　the　occurrence　of　a　single-line-to-ground　fault,　the　change　law　of　the　three-phase　voltage　is　affected　by　the　zero-sequence　overvoltage,　leading　to　misjudgment　of　the　fault　phase.　Accordingly,　this　paper　proposes　a　fault　phase　selection　method　based　on　active　current　injection　that　can　adapt　to　asymmetric　distribution　networks.　The　fault　phase　is　selected　by　injecting　current　and　calculating　the　equivalent　power　supply　voltage　of　the　faulty　line　without　increasing　the　ground-fault　current.　The　high　sensitivity　of　the　proposed　fault　phase　selection　method　was　verified　for　high　impedance　faults　through　software　simulations　and　prototype　experiments.　Moreover,　the　zero-sequence　overvoltage　can　be　suppressed　by　a　single-phase　flexible　arc　suppression　device　during　the　normal　operation　of　distribution　networks.　The　ground-fault　current　can　be　quickly　suppressed　at　different　ground-fault　locations　and　resistance　values,　ensuring　the　extinguishment　of　the　ground-fault　arc.