Effect of Defect Location on Decomposition Components Detection in SF₆ Gas Under Partial Discharge

Partial discharge (PD) inside gas-insulated power equipment is an important cause of sudden failures such as flashover and breakdown in equipment. In order to study the effect of defect location on decomposition components detection in SF₆ gas under partial discharge during the operational conditions of gas-insulated power equipment, a 252 kV full-scale gas-insulated switchgear (GIS) in-situ detection technology experimental platform was built. On this basis, a SF₆ gas decomposition components in-situ detection system was constructed. Through continuous partial discharge experiments, the gas chromatograph was used to detect the characteristic components generated by the decomposition of SF₆ gas, including CO, CO₂, CF₄, and C₂F₆ changing with the defect location. The results show that under the conditions of continuous partial discharge monitoring on site, no obvious formation of sulfur compounds is detected. When organic insulating materials participate in partial discharge, the CF₄ content increases with increasing discharge time, and CF₄ is expected to be used as the judgment basis of surface discharge in GIS. The amount of C₂F₆ produced is very large, the C₂F₆ content increases with increasing discharge time, and the amount of C₂F₆ produced decreases with increasing diffusion distance. C₂F₆ is expected to be used as the judgment basis for partial discharge in GIS. The CO content and CO₂ content show a decreasing trend and increasing trend respectively with the increase of discharge time, and the change of these two decomposition components decreases with the increase of diffusion distance.