Simultaneous and Dynamic Detection of SF₆ Decomposition Products under partial discharge defect of Gas-insulated Power Equipment by Fiber-Enhanced Raman Spectroscopy

SF ₆ decomposition product analysis can effectively obtain the health status of gas-insulated power equipment (GIPE). In this paper, to solve the drawbacks of aging, cross-interference, and time-sharing detection analysis of common gas detection technologies, a fiber-enhanced Raman spectroscopy (FERS) sensing system is used to realize the simultaneous and dynamic measurement of multiple SF ₆ decomposition products. A hybrid collaborative fluorescence filtering method is proposed to simply and effectively improve the sensitivity of FERS by 2.7 times. The characteristic peaks for simultaneous quantitative and qualitative determination of SF ₆ decomposition products are determined (811 cm ^-1 for SOF ₂ , 851 cm ^-1 for SO ₂ F ₂ , 861 cm ^-1 for COS, 913 cm ^-1 for CF ₄ , 1156 cm ^-1 for SO ₂ , 1395 cm ^-1 for CO ₂ and 2150 cm ^-1 for CO), and the corresponding simultaneous detection limit can be obtained as: 5.95 ppm·bar for SOF ₂ , 3.75 ppm·bar for SO ₂ F ₂ , 1.89 ppm·bar for COS, 5.82 ppm·bar for CF ₄ , 2.23 ppm·bar for SO ₂ , 6.19 ppm·bar for CO ₂ and 14.82 ppm·bar for CO with the laser power of 200 mW and the exposure time of 60 s. Finally, the dynamic analysis of SF ₆ decomposition gases produced by metal protrusion partial discharge defect model is also achieved. The designed FERS sensing system fully demonstrates its ability to simultaneously and dynamically analyze the SF ₆ decomposition products, which lays the foundation for more accurate and earlier diagnosis of SF ₆ GIPE failures.