The　concepts　of　integrated　impedance　of　positive-sequence　bus-bar　fault　component　and　those　of　negative-sequence　integrated　impedance　and　zero-sequence　integrated　impedance　are　proposed.　By　means　of　analyzing　the　characteristics　of　above-mentioned　integrated　impedances　under　the　faults　inside　and　outside　the　bus-bar　protection　zone,　three　bus-bar　protection　principles　based　on　integrated　impedance　of　positive-sequence　bus-bar　fault　component　and　those　of　negative-sequence　integrated　impedance　and　zero-sequence　integrated　impedance　are　established　by　amplitudes　and　arguments　of　the　sequence　component　integrated　impedances　respectively.　For　the　three　protection　principles　the　bus-bar　faults　inside　and　outside　the　potection　zone　show　features　with　obvious　differences,　so　the　criteria　are　simple　and　easy　to　set,　besides　the　proposed　protection　principles　themselves　immune　to　the　transition　resistance　and　the　out-flowing　current　of　bus-bar　fault　inside　the　protection　zone　under　the　one　and　a-half　circuit　breaker　layout.　Under　the　CT　saturation　caused　by　fault　outside　bus-bar　protection　zone　the　bus-bar　protection　can　be　blocked　to　prevent　protection　misoperation　by　the　discriminating　criterion　of　CT　saturation　that　is　constituted　by　phase　angles　of　sequence　component　integrated　impedances;　under　the　CT　saturation　during　the　fault　inside　bus-bar　protection　zone,　the　performance　of　the　protection　is　not　affected　and　the　protection　can　operate　fast　and　reliably.　The　bus-bar　protection　principle　based　on　integrated　impedance　of　positive-sequence　fault　component　can　reflect　various　types　of　bus-bar　faults　and　it　makes　the　possibility　of　rapidly　switching　off　the　most　severe　three-phase　short-circuit　fault;　the　bus-bar　protection　principles　based　on　negative-sequence　and　zero-sequence　integrated　impedances,　which　is　not　affected　by　system　oscillation,　can　be　applied　in　a　long-term　after　the　fault,　and　the　protection　can　still　be　sensitively　operate　under　high-resistance　earth-fault.　The　proposed　three　protection　principles　can　constitute　an　integrated　protection　scheme.　The　effectiveness　and　feasibility　of　the　proposed　protection　principles　are　verified　by　results　of　EMTP　simulation.