Application and Practice of X-ray Imaging Technology in Fault Diagnosis for GIS and GIL Equipment

Addressing the limited direct observability of internal structures in enclosed power apparatuses such as gas-insulated switchgear (GIS) and gas-insulated transmission lines (GIL), this study examines the on-site safety requirements and engineering applicability of portable X-ray imaging and develops a field-deployable methodology for non-disassembly radiographic inspection and interpretation. Specifically, we analyze SF₆ decomposition products following X-ray exposure to assess potential impacts on the insulating gas within the equipment; in GIS maintenance, we validate overhaul quality by comparing radiographs obtained under normal conditions with those acquired after maintenance; and in on-site GIL applications, we configure the radiographic setup to accommodate spatial constraints and conduct multi-angle exposures with comparative analysis at critical locations. The results indicate that, under the inspection conditions employed, X-ray irradiation does not induce SF₆ gas decomposition; radiographic comparison can identify positional deviations of internal GIS components, thereby supporting maintenance quality evaluation; and multi-angle radiography coupled with comparative interpretation can effectively determine internal structural relationships and integrity in GIL, providing an evidentiary basis for post-maintenance verification and safety assessment. Overall, the findings suggest that, conditional on ensuring the environmental safety of SF₆, portable X-ray imaging enables non-destructive, non-disassembly visual verification of internal structures at key GIS/GIL locations, thereby complementing conventional external inspection and online monitoring by improving the identification of concealed defects and strengthening maintenance acceptance, with substantial potential for broader engineering deployment.