Insights into Stochastic Flashover Induced by Random Surface Charges

Due to the stochastic nature of surface charge accumulation, DC-GIL spacers often exhibit unpredictable flashover under operating voltages. This study investigates the relationship between surface charge distribution and flashover behavior. Results show that flashover voltage is weakly negatively correlated with charge non-uniformity, while its dispersion is strongly positively correlated with charge variability, indicating that a more reproducible surface charge distribution leads to more stable flashover performance. Furthermore, increasing the normal electric field component or applying an appropriate temperature gradient can effectively improve charge uniformity and reproducibility, thereby enhancing the insulation reliability of DC-GIL spacers. These findings provide guidance for the design and optimization of DC insulation system.