简介：Radiointerference(RI),asanaftereffectofcoronadischarge,isanimportantresearchtopicinthefieldofelectromagneticcompatibility,whereexcitationfunctionisappliedbroadlytothepredictionofRIlevel.ThispaperpresentsthetheoryofexcitationfunctionmethodusedintheRIlevelprediction.Then,somepracticalproblemsrelatedtothismethodarediscussed.Thepropagationprocedureofcoronacurrentissolvedbythephase-modaltransformation,andtheimpedancematrixofmultitransmissionlinesiscalculatedbyadoublelogarithmicapproximatemodelofCarson'sGround-Returnimpedance.Atthesametime,inordertocalculatetheRIlevelwhentotallinecoronaisassumed,ananalyticalformulaisdeducedforintegraloperation.Basedontheabovesolutions,analgorithmispresentedandappliedtothepredictionofRIlevelofapracticaloverheadtransmissionline.Comparisonofpredictionandmeasurementresultsindicatesthatthealgorithmproposedinthispaperiseffectiveandfeasible.