Micro-Zone Charge Migration Behavior of Bubble Defects in Epoxy Resin

As a common defect in basin insulators, bubbles can cause local electric field distortion inside the epoxy resin under high field strength, affect the dielectric properties of the insulation, and even lead to insulation failure. However, the microscopic mechanism of bubble affecting material deterioration is not clear at present. The existed studies mainly use macroscopic testing methods, lacking of direct research on micro-zone charge transport behavior in bubble regions. In this paper, the micro-zone charge distribution of in bubble region in epoxy resin was studied by Kelvin probe force microscope (KPFM). The results show that the bubble, as deep traps, affect the micro-zone charge migration by charging themselves, and the bubble is more likely to be negatively charged. The research results will be of great significance for the optimal design of high performance basin insulators, and the study method can be further used to track and monitor the aging state of insulation equipment.