We　investigated　the　impact　of　the　photoconductive　properties　of　crystalline　silicon　solar　cells,　having　a　SiNx　passivation　film,　on　potential　induced　degradation　(PID)　using　voltage-corona　(V-Q)　and　self-adjusting　stead　state　(SASS)　tests.　The　experimental　results　show　that　the　conductivity　of　SiNx　on　the　cell　surface　was　gradually　enhanced　by　the　increase　in　refractive　index,　which　effectively　decreased　the　accumulated　charge　on　the　cell　surface.　Thus,　changes　in　the　conductivity　of　SiNx　were　found　to　be　the　cause　of　the　different　PID　performance　of　the　modules.　The　present　work　provides　a　theoretical　basis　for　solving　the　PID　problem　of　solar　modules　and　power　stations,　and　the　exploration　of　the　V-Q　and　SASS　techniques　provides　a　new,　convenient　method　and　corresponding　basis　for　testing　the　PID　performance　of　solar　cells　during　industrial　production.