The Detection of CO Gas Based on Non-resonant Photoacoustic Spectroscopy

CO gas is the product of solid insulating material in the fault area of SF6in GIS. The fault type can be effectively evaluated by detecting the content of Co. Based on the photoacoustic spectroscopy detection technology, the detection platform of non resonant photoacoustic spectroscopy is built. Through the verification of the coherence formula of photoacoustic cell volume, it is obtained that in the case of non resonance, the intensity of photoacoustic signal is negatively correlated with the radius of photoacoustic cell and independent of the length of photoacoustic cell. A photoacoustic cell with a radius of 3 mm is designed. Before the experiment, the system noise of the experimental platform is detected, and the noise value is 0.322mv. The quantitative detection experiment of CO gas is carried out, and the correlation coefficient of 0.993 is obtained. The inversion of CO gas concentration signal is calculated, and the relationship between gas content and photoacoustic signal is obtained. Finally, the detection limit of CO and the signal-to-noise ratio are explored, and the signal-to-noise ratio of the lowest concentration is 2.44. Thus, the detection limit of CO gas is 8.2ppm. Through the experiment and exploration of quantitative detection of CO gas, it lays a foundation for effectively evaluating the operation status of power equipment.