Doubly　fed　induction　generator　(DFIG)　based　wind　turbine　(WT),　as　a　highly　penetrated　power　source　in　modern　power　systems,　has　different　fault　current　contribution　from　traditional　power　sources.　It　has　significant　impacts　on　distance　relay＇s　performances　and　may　result　in　maloperation.　In　this　paper,　the　impacts　of　DFIG-based　WT＇s　fault　current　on　the　performances　of　distance　protection　are　studied　in　terms　of　apparent　impedance　trajectories　and　fault　current　expressions,　for　the　symmetrical　faults.　Based　on　the　apparent　impedance　trajectories　and　EMTP　simulations,　a　new　kind　of　maloperation　is　discovered　that　the　zone-1　distance　relay　of　the　lines　connecting　to　DFIG-based　wind　farms　will　overreach.　And　the　following　analysis　indicates　that　the　transient　components　of　DFIG-based　WT＇s　fault　current　are　the　underlying　reasons.　With　those　understanding,　suggestions　are　provided　to　help　prevent　the　overreach　by　optimizing　the　setting　of　zone-1　distance　relay.　©　2019　Institution　of　Engineering　and　Technology.　All　rights　reserved.