Aging characteristics of epoxy resin discharged by very fast transient overvoltage in SF6

Surface flashover on epoxy resin (EP) materials, as driven by very fast transient-pulse overvoltage, was studied in this research. Flashover experiments were conducted using a nanosecond pulsed power supply in SF6, and then the morphology and the elemental composition of the material surface after different degrees of aging treatment were analyzed. The results show that, the flashover voltage of EP materials driven by nanosecond pulses increases with the increment of SF6pressure. While, with increasing pulse repetition frequency (PRF), the flashover voltage decreases: this trend is especially significant under a lower PRF. In the aging process, the EP on the material surface in front of the electrodes was cleared by the electrical arc, exposing the alumina particles in the lower layer of the material. As the aging time increases, the organic compounds, which were bubble-shaped and sputtered out by the electrical arc, gradually covered the surface of the alumina particles. In addition, the surface morphology in the area closer to the electrodes changes more significantly, while the material surface below the electrodes, and at the edge of the discharge area, experiences less damage. This research is of significance to those seeking to modify the insulating performance, and aging resistance, of EP insulating materials.