Two　questions　about　zero-sequence-reactance　relay　to　overcome　the　disadvantages　of　high　fault　resistance　for　single　phase　to　earth　fault　of　high　voltage　transmission　lines　are　discussed　in　this　paper.　The　first　question　is　about　the　phase　difference　between　the　measured　zero-sequence　current　and　voltage　at　fault　position　for　un-balanced　transmissionlines.　The　second　question　is　about　the　＇in-phase＇　problem　in　reactance　relays　(or　fault　component　reactance　relays).　This　paper　analyzes　the　two　questions　theoretically　and　the　reactance　relay　is　improved　by　a　new　discriminative　principle.　The　capability　against　thefault　resistance　is　largely　enhanced　by　the　improved　schemes.　©　2013　Universitas　Ahmad　Dahlan.