The　existing　four　linear　section　location　methods　are　all　established　based　on　the　three-phase　fault　current　direction.　When　a　single-phase　grounding　fault　occurs　in　a　neutral　noneffectively　grounded　system,　these　methods　are　no　longer　applicable.　This　study　proposes　a　linear　optimization　method　for　section　location　suitable　for　single-phase　ground　fault　in　the　neutral　noneffectively　grounded　system.　It　presents　an　improved　transient　zero-sequence　current　direction　identification　algorithm　based　on　line　voltage　to　accurately　determine　a　transient　zero-sequence　current　direction　under　single-phase　grounding　faults　without　zero-sequence　voltage　information.　Second,　it　proposes　a　suitable　linear　section　location　model　for　single-phase　ground　faults　as　per　the　transient　zero-sequence　current　direction＇s　distribution　characteristics　after　the　single-phase　ground　fault.　Finally,　it　is　verified　in　different　feeders　that　the　proposed　method　can　quickly　and　accurately　locate　the　fault　section　after　the　single-phase　ground　fault　occurs　in　the　neutral-point　ineffectively　grounded　distribution　system.　©　1963-2012　IEEE.