Abstract: Gas Insulated Switchgear and Gas Insulated Transmission Line hold significant potential in high-voltage power transmission. However, the occurrence of internal insulator flashover faults critically undermines their safe and stable operation. Surface charge has been widely recognized as a crucial factor affecting the flashover voltage of insulating components. The accumulation and dissipation characteristics of surface charges on insulators after prolonged operational aging remain uncertain, necessitating an in-depth investigation into the changes in surface charges on aged epoxy resin insulators. To address this, an apparatus for measuring surface charge was constructed to examine the dissipation of surface charges under various thermal aging conditions. The study explored the dissipation characteristics of charges under different voltage magnitudes and polarities. Results indicated that thermal aging increases the glass transition temperature of the epoxy samples, thereby reducing the rate of surface charge dissipation. Under identical voltage magnitudes, the accumulation of surface charges was greater with the application of negative polarity voltage compared to positive polarity. The dissipation of surface charges on the insulator surfaces approximately follows an exponential decay, with a time constant ranging from 10⁴ to 10⁵ seconds. The findings on surface charge dissipation of epoxy resin samples under various conditions provide a novel perspective for assessing the aging degree of insulating components. These insights can serve as a reference for fault analysis and reduction in actual engineering applications.

Key words: surface charge, epoxy resin, thermal aging, gas insulated switchgear