The application of gamma-ray computed tomography in solid insulator diagnostics

A diagnostic technique using gamma-ray computed tomography (CT) to characterize the internal anomalies of solid insulators in gas-insulated equipment is described. Results of CT scans on three types of insulators which were suspected of internal defects are presented. Voids, discharge channels and density variations that resulted from inhomogenous mixing during the casting process were detected and identified by the CT scans in a noninvasive manner. Merits and limitations of applying the gamma-ray CT technique in diagnostics of solid insulators are presented.<>