Study on SF6 gas decomposition products of typical GIS defect models by infrared detection

Detection of SF₆ gas decomposition products has been increasingly used for monitoring the insulation condition of Gas Insulated Substation (GIS) for its advantages, comparing to traditional partial discharge detection methods, such as excellent anti-interference ability, explicit calibrating method and so on. In this paper, based on the setup of two typical GIS defect models including needle-to-plate and insulator surface, gas decomposition products were detected by IRprestige-21 Fourier transform infrared (FTIR) spectrophotometer. Types, concentrations and trends of typical gas decomposition products were analyzed. Moreover, influences of acquisition and transportation duration on detection results were studied. Obvious differences were found among infrared spectra of gas decomposition products from different defect models, which verifies the feasibility of IR gas decomposition detection method for GIS fault detection and diagnosis.