High-Altitude　electromagnetic　pulse　(HEMP)　can　produce　Electromagnetic　interference　(EMI)　on　the　generator　system.　Without　a　precise　machine　model,　over-voltage　on　the　stator　winding　of　generator　cannot　be　accurately　evaluated,　and　this　is　a　new　challenge　for　the　design　of　nuclear　power　plant　generator　system.　Therefore,　the　paper　establishes　the　motor　model　by　considering　multi-conductor　transmission　line,　and　employs　this　model　to　design　a　set　of　precautions.　At　first,　the　expression　of　HEMP　and　coupling　channel　of　HEMP　are　performed　to　analyze　magnitude　and　waveform　of　over-voltage　caused　by　HEMP.　Then,　a　novel　stator　winding　model　is　developed　which　bases　on　the　analysis　for　multi-conductor　transmission　line.　This　model　considers　the　influence　of　E1　on　frequency-dependent　parameters,　and　the　voltage　of　winding　per　turn　under　HEMP　can　be　calculated　fast　and　accurately　via　it.　The　proposed　approach　can　be　validated　through　a　three-dimensional　electromagnetic　simulation　software　based　on　the　finite　integration　method.　Finally,　couple　of　precautions　are　derived　based　on　the　existing　lightning　protection　measures　and　the　above　analysis.　©　2017　CPSS.