Research on Microdefects of GIS Insulated Tie Rod Based on Photon Detection

This paper proposes a highly sensitive and convenient method for measuring micro-defects in GIS insulating pull rods using the photon counting principle. We designed a micro-optical detection platform and a photon detection fixture specifically for insulating pull rods. Photon measurement tests were conducted on pull rods with micro-defects at low voltage. The results were analyzed and discussed alongside electric field simulation calculations. The results indicate: (1) In actual field operations, surface metal impurity defects pose the greatest risk to insulated pull rods, followed by bubble defects, internal metal impurity defects, and white spot defects. (2) In the 4-7kV voltage range, non-defective insulated pull rods exhibit significantly fewer photons compared to defective ones. (3) Internal defects are more visible under low field conditions, whereas surface defects become more apparent under high field conditions. This method effectively distinguishes between internal and surface defects in high-field environments. The proposed method offers a convenient and highly sensitive approach to detecting micro-defects in insulated pull rods, ensuring high-quality screening before they are deployed in the network.