Most　of　the　phase-to-ground　parameters　induced　between　distribution　lines　and　ground　are　asymmetric,　which　can　result　in　the　generation　of　unbalanced　voltage,　shifting　the　neutral　point　voltage.　For　compensated　distribution　networks,　the　existence　of　an　arc　suppression　coil　can　increase　the　influence　of　asymmetric　parameters　and　exacerbate　the　deviation　of　neutral　point　voltage.　Maintaining　the　balance　of　three-phase　voltage　is　a　prerequisite　not　only　for　the　stable　operation　of　the　distribution　networks　but　also　for　improving　the　reliability　of　single-phase　ground　fault　detection.　This　article　proposes　a　novel　online　split-phase　identification　of　asymmetric　parameters　between　distribution　lines　and　ground　for　unbalanced　voltage　compensation　based　on　power　electronics.　First,　an　adaptive　active　current-type　compensation　method　based　on　power　electronics　is　proposed;　it　can　adapt　to　compensate　for　three-phase　unbalanced　voltage　with　different　neutral　point　grounding　styles.　Second,　particle　swarm　optimization　is　used　to　realize　the　online　split-phase　identification　of　the　phase-to-ground　parameters　of　the　distribution　power　lines.　The　identified　parameters　are　used　to　calculate　the　reference　value　of　the　compensation　current　and　the　asymmetry　of　each　phase-to-ground　parameter.　Finally,　the　feasibility　and　effectiveness　of　the　proposed　method　are　verified　by　simulation　and　experiment.　©　1986-2012　IEEE.