The　measured　spectral　line　based　on　frequency　domain　dielectric　spectrum　contains　multiple　superpositions　of　conductance　and　polarization　processes.　In　view　of　the　lack　of　methods　to　separate　the　polarization　and　the　conductance　processes　and　the　lack　of　unique　methods　to　characterize　the　model　conductance　parameters,　the　micro　conductance　processes　are　studied　in　depth　according　to　the　real　and　imaginary　Kramers-Kronig　relation.　Firstly,　different　water　content　insulation　samples　were　prepared　during　the　laboratory　conditions,　and　dielectric　lines　in　frequency　domain　were　obtained　by　measurement.　Secondly,　according　to　the　k-K　relation,　the　relaxation　loss　spectrum　line　is　obtained　by　numerical　integration　of　the　measured　real　part　of　the　complex　polarization　spectrum　line,　and　then　the　conductivity　loss　spectrum　line　is　obtained.　Finally,　the　least　square　method　is　used　to　fit　the　conductivity　spectrum　line　and　calculate　the　conductivity　value.　The　experimental　results　show　that　the　conductance　of　the　virtual　part　of　the　repolarization　measurement　can　be　separated　from　the　relaxation　loss　line　by　k-K　transformation,　and　the　dc　conductance　can　be　calculated.　At　the　same　time,with　the　oil-paper　insulating　sample＇s　water　content　increasing,　its　electrical　conductivity　is　gradually　enhanced.　©　Published　under　licence　by　IOP　Publishing　Ltd.