Detection of Micro-Defects in GIS Epoxy-Alumina Insulation Based on Phase Resolved Photon Counting

Micro-defects in epoxy-alumina insulation of gas-insulated switchgear (GIS) significantly compromise operational safety. This study proposes a phase resolved photon counting (PRPC) measurement-based detection method for effective identification of such micro-defects. Epoxy-alumina samples were fabricated with two representative defect types: scratch defects and surface metal-attachment defects. PRPC measurements were conducted under varying voltage levels to obtain characteristic discharge patterns. Experimental results demonstrate a significant positive correlation between PRPC signal intensity and both applied voltage magnitude and defect severity. Moreover, the extracted feature parameters demonstrate strong responsiveness to the insulation condition of defective samples. This investigation establishes a novel and reliable approach for micro-defect detection in GIS epoxy-alumina insulation systems.