The　equivalent　impedance　parameters　of　loads　have　been　widely　used　to　identify　and　locate　the　harmonic　sources.　However,　the　existing　calculation　methods　suffer　from　outliers　caused　by　the　zero-crossing　of　the　denominator.　These　outliers　can　result　in　inaccuracy　and　unreliability　of　harmonic　source　location.　To　address　this　issue,　this　paper　proposes　an　innovative　method　of　equivalent　impedance　parameter　calculation　of　three-phase　symmetrical　loads　that　avoid　outliers.　The　correctness　and　effectiveness　of　the　proposed　method　are　verified　by　simulations　on　Simulink　using　actual　monitoring　data.　The　results　show　that　the　proposed　method　is　not　only　simple　and　easy　to　implement　but　also　highly　accurate.　　©　2013　State　Grid　Electric　Power　Research　Institute.