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Research progress on photoacoustic SF6 decomposition gas sensor in gas-insulated switchgear

In the power industry, sulfur hexafluoride (SF6) as an insulating gas is widely used in gas-insulated switchgears (GISs). Owing to the latent inner insulation defects of GIS, various SF6 gas decompositions are generated in the process of partial superheating and partial discharge (PD). The decomposition components and concentrations are different under different PD types. A number of gas sensors were reported for the detection of these decompositions. Photoacoustic spectroscopy (PAS) gas sensors have been developed for many applications owing to their high sensitivity and selectivity, such as gas pollutant detection, industrial process control, and non-invasive medical diagnosis. Due to the SF6 physical constants being different from that of nitrogen (N2) or air, the sensor structure should be redesigned. A detailed review of four different types of PAS-based gas sensors is discussed and compared.