Study onLowCurrent ArcsonSurfaces ofDielectric Materials

External polymer insulators arewidely used fortheir superior performance. Onemechanism that can leadtoserious damage toapolymer insulator islow current stable arcing onits surface. This paper describes experimental research towardsquantifying the probability offormation oflowcurrent, stable arcs between twodroplets onthesurfaces ofdielectric materials withdifferent hydrophobicity, especially on silicone rubber based materials. Video andstill cameras areusedduring thedischarge process. Theresults show itisdifficult toformastable arconthetopsurface of silicone rubber based materials because thetwowater droplets join together rapidly after powerenergization, thereby extinguishing thearc.Ontheunderside ofa horizontal plate, itisrelatively easytoformstable arcs. Itcanbeobserved that thestability ofalowcurrent arc mainly depends uponthehydrophobicity ofthematerial. Various factors that influence thecharacteristics ofthe arc,suchas current andsalinity ofwaterare investigated. Theoretical analysis isalso presented.