Detection of C4F7N/CO2 Gas Mixture Decomposition Products Based on Photonic Crystal Fiber

As a potential replacement to SF ₆ , C ₄ F ₇ N/CO ₂ gas mixture has been gradually applied to gas insulated lines (GIL). Partial discharge and local overheat inside the GIL often lead to the decomposition of the insulating medium, and the C ₄ F ₇ N/CO ₂ gas mixture will decompose into characteristic decomposition products such as CO, CF ₄ , C ₂ F ₆ . The internal operating state of the insulating devices can be identified by detecting the types and concentrations of the decomposition components. Therefore, it is necessary to carry out the detection of decomposition products of C ₄ F ₇ N/CO ₂ gas mixture. This paper developed a carbon monoxide (CO) gas detection system based on photonic crystal fiber for the C ₄ F ₇ N/CO ₂ filled GIL. In this study, photonic crystal fiber was used as the gas cell, and preliminary detection studies of CO with different concentrations were carried out by fiber loop ring-down spectroscopy.