The paper deals with a series of improvements from design structure to testing techniques including on-site testing for 550kV gas-insulated busbar (GIB) using SF6 to improve the insulation reliability against metallic particles. The inner surface of the enclosure, unlike conventional designs, was dielectric coated with a dielectric material to suppress the particle motions. The particle trap was upgraded from the conventional “slit type” to “opening hole type” at the bottom of the enclosure to ensure reliable capture of metallic particles and to prevent their re-movement. AE sensors mounted on the top of the enclosure enabled the detection of the accurate length and position of the particles. This technique allowed for confirmation via AE sensors that the particles were successfully captured in the improved particle trap. Finally, simple on-site conditioning tests became feasible by using system voltage instead of conventional stepwise-voltage-increase pattern, allowing for a simplified testing method without the use of testing transformers.
Sasamori et al. (Sat,) studied this question.