Power　tap-off　from　shield　wires　of　high　voltage　overhead　transmission　lines　is　associated　with　electrostatic　induction　voltage　of　shield　wire　and　equivalent　capacitance　of　power　tap-off　circuit,　which　will　be　affected　by　the　rated　voltage.　In　this　paper,　the　equivalent　circuit　parameters　of　typical　transmission　lines　at　rated　voltages　from　110　kV　to　1000　kV　in　China　are　investigated.　The　electrostatic　induction　voltage　and　equivalent　capacitance　are　calculated　by　Maxwell＇s　electrostatic　equations　as　well　as　Thevenin＇s　equivalence　principle.　The　results　show　that　the　electrostatic　induction　voltage　is　increased　with　the　increase　of　the　rated　voltage,　while　the　equivalent　capacitance　is　slightly　decreased　with　the　increase　of　the　rated　voltage.　The　conducting　line　arrangement　is　also　considered.　The　relationships　between　the　equivalent　circuit　parameters　and　the　rated　voltage　are　built　up,　which　can　provide　a　reference　for　the　power　tap-off　from　insulated　shield　wires.　©　2018　IEEE.