The　fault　phase　detection　(FPD)　of　single-line-to-ground　fault　(SLGF)　is　important　for　active　arc　suppression　devices　(AASD),　but　it　is　challenging　when　considering　asymmetrical　line　parameters　and　different　neutral　grounding　types.　To　improve　the　reliability　of　FPD,　this　article　proposes　an　FPD　method　based　on　the　fusion　of　amplitude　and　phase　angle　characteristics.　First,　when　an　SLGF　occurs,　the　amplitude　and　phase　angle　characteristics　of　the　three-phase　source　voltage　are　analyzed.　Then,　the　phase　angle　of　the　fault　phase　source　voltage　is　calculated　based　on　the　derived　amplitude　and　phase　angle　characteristics,　which　are　compared　with　the　measured　phase　angle　of　the　three-phase　source　voltage,　respectively.　According　to　the　FPD　criterion,　the　fault　phase　can　be　determined.　In　addition,　an　FPD　device　(FPDD)　featuring　convenient　installation　has　been　designed.　The　FPD　results　are　sent　to　AASD,　if　the　fault　phase　voltage　can　be　effectively　suppressed,　the　FPD　results　are　correct.　The　proposed　method　has　been　experimentally　validated　on　380　V　and　10　kV　experimental　platforms.　©　1963-2012　IEEE.