The occurrence of foreign object-induced discharge faults during switching operations of ultra/high-voltage gas-insulated switchgear (GIS) tested by conventional static withstand voltage tests can reflect the limitations of detecting latent foreign object defects by traditional static withstand voltage tests. This paper presents a novel method and procedure for conducting seismic endurance tests on GIS. Mechanical vibrations are externally applied during the GIS endurance test process

aiming to stimulate and enhance the movement of latent metal foreign objects to achieve efficient detection. Furthermore

a test platform for external excitation and vibration resistance was established for a 550 kV real-type GIS. This platform was used to investigate the effectiveness of a new testing method for detecting hidden defects such as flange gap concealment

shield cover concealment

and high-density irregularities. The results indicate that latent metal particle defects exhibit a “static dormant” state under stepped static test voltages

and neither ultrasound or partial discharge or breakdown occurs

making them difficult to detect effectively. Subsequently

during external vibration endurance tests

the latent metal particles show a “release” state

displaying intermittent jumping or continuous dancing movements under different voltage steps

and ultrasound and partial discharge signals significantly increase. This validates the effectiveness of the GIS external vibration withstand test in detecting latent metal particles

offering a simple and efficient insulation testing method to enhance the insulation reliability of GIS equipment.