基于悬臂梁增强型光声光谱的SF_6特征分解组分H_2S定量检测

H_2S作为SF_6分解产生的关键特征组分,能够有效反映SF_6气体绝缘电气设备内部绝缘故障的严重程度及故障是否涉及固体绝缘材料。采用新型硅微悬臂梁传声器与分布反馈式半导体激光器搭建了悬臂梁增强型光声光谱痕量气体检测系统,以H_2S气体v1+v2+v3泛频吸收谱带中心波数为6 336.62 cm-1的吸收谱线作为研究对象,仿真研究了H_2S气体的红外吸收特性,试验研究了H_2S气体悬臂梁增强型光声光谱响应特性,采用最小二乘回归分析了H_2S气体光声信号与其体积分数的关系。结果表明,在气体吸收未饱和的情况下,光声信号强度与H_2S体积分数之间存在良好的线性关系,系统对N2中痕量H_2S的检测下限为0.84×10-6,对SF_6中痕量H_2S的检测下限为1.75×10-6。研究结果为采用SF_6分解组分法判断设备内部绝缘故障类型和严重程度提供了有力的数据支持。

The Quantitative Detection of SF6 Characteristic Decomposition Component H2 S Based on Cantilever Enhanced Photoacoustic Spectrometry

As one of the key characteristic components caused by SF6 decomposition in the SF6 gas insulated electrical equipment,H2 S could effectively reflect the severity of the internal insulation faults and whether the faults involve solid insulation material. The paper builds a cantilever enhanced photoacoustic( PA)spectrometry ( CEPAS)trace gas detection system based on the micro cantilever microphone and distributed feedback-diode laser. The characteristic absorption line of H2S with a central wavenumber of 6 336. 62 cm -1 in v1 + v2 + v3 overtones absorption band is selected as the study objective. The frequency response of the CEPAS detection system is tested,and the quantitative relationship between the PA signal amplitude and the gas concentration is studied. The results show that there is a good linear relationship between the PA signal amplitude and the gas concentration. The detection limit of the CEPAS system for tracing H2S in N2 is 0. 84*10 -6,and H2S in SF6 is 1. 75*10 -6. It may be a powerful data supplement for the SF6 decomposition components method in recognizing the internal fault category and severity of the SF6 gas insulation electrical equipment.