Under DC high voltage, the surface of GIS spacers are easy to accumulate charges. Excessive charge accumulation will distort the electric field, which will seriously threaten the safe and stable operation of the insulation system. Direct fluorination has become one of the most important means of surface modification of polymeric insulation materials due to its simple process, mature technology and low cost, providing a method for surface modification of epoxy spacers. This paper reviews the research status of direct fluorination of epoxy insulation at domestic and foreign, and summarizes the physiochemical characteristics, basic electrical properties, DC flashover performance and discharge resistance of fluorinated layer. Under usual fluorination conditions, fluorine atoms form a micron-thick fluorinated layer on the surface of the epoxy insulation through substitution or addition reactions. Such the fluorinated layer can suppress charge accumulation on the epoxy insulation surface, due to its high surface conductivity. Due to the formation of fluorinated layer, the DC flashover performance and discharge resistance of epoxy insulation are significantly improved. Finally, the future of the direct fluorination method in the industrial application of actual spacer is prospected.

epoxy insulator,direct fluorination,actual spacer,dc flashover,discharge resistance