Find in Library

The accurate and effective detection of SF₆ decomposition components inside a gas-insulated switchgear (GIS) is crucial for equipment fault diagnosis and condition assessment. The current method for detecting SF₆ decomposition components involves gas extraction at the GIS inlet, which only provides limited information on the decomposition component content. Therefore, there is a need to explore more effective ways to obtain internal gas component information within GIS. In this study, we propose a graphene-coated microfiber gas detection method for SO₂. We establish a physical simulation model of the microfiber and analyze the sensing mechanism of the microfiber diameter and cladding refractive index changes in its evanescent field. A graphene-coated microfiber gas sensor was prepared using a drop-coating method, and a fiber loop ring-down (FLRD) gas detection system was constructed for the experimental studies on SO₂ gas detection. The results demonstrated that the graphene-coated microfiber exhibits an excellent gas-sensitive response to SO₂ and achieves trace-level detection at room temperature. The concentration range of 0 to 200 ppm showed good linearity, with a maximum detection error of 4.76% and a sensitivity of 1.24 ns/ppm for SO₂. This study introduces an all-fiber method for detecting SF₆ decomposition components, offering a new approach for online monitoring of SF₆ decomposition components in GIS equipment using built-in fiber-optic sensors.