基于激光光声光谱超高灵敏度检测SF_6分解组分H_2S

High Sensitive Detection for SF_6 Decomposition Component of H_2S Based on Laser Photoacoustic Spectroscopy

H_2S是SF_6气体绝缘设备中放电故障诊断的特征组分之一;针对H_2S在红外波段吸收系数小,传统光学检测方法对H_2S检测灵敏度较低的问题,结合大功率光纤激光放大技术、共振式激光光声光谱技术、波长调制光谱技术和二次谐波检测技术,提出了一种基于光纤放大激光光声光谱的SF_6分解组分H_2S气体的超高灵敏度检测方法;采用近红外可调谐窄线宽分布反馈激光二极管级联高饱和输出功率掺饵光纤放大器作为光声激发光源,搭建具有超高灵敏度的激光光声光谱微量H_2S气体检测系统。结果表明:当测量时间为100s时,该系统对SF_6背景中H_2S气体的检测极限达到1.5×10^(-8)。

H2S is one of characteristic components for discharge faults diagnosis in the SF6 gas insulated device.Due to the small absorption coefficient of H2S gas in the near-infrared band,the detection sensitivity is difficult to improve with traditional optical detection methods.To solve this problem,we propose an enhanced laser photoacoustic detection method,which combines the technologies of high-power fiber laser amplifying,resonant laser photoacoustic spectroscopy,wavelength modulation spectroscopy,and second-harmonic detection,for high sensitive detection of H2S decomposed by SF6.By cascading a near-infrared tunable narrow linewidth distributed feedback laser diode with a high saturation output power erbium doped fiber amplifier as the photoacoustic excitation light source,we develop a high-sensitivity laser photoacoustic spectroscopic system for trace H2S gas detection.The results show that the detection limit in the background of SF6 is achieved to be 1.5×10-（-8） with the measurement time of 100 s.