基于共振型高灵敏度光声光谱技术探测痕量乙炔气体浓度
发布时间：2018-12-30 12:28
【摘要】：乙炔气体作为判断变压器运行状态的一种故障气体,其浓度的高低反映了变压器的运行状况,因此对其浓度的探测在变压器的维护中具有重要意义。为了准确探测变压器运行过程中产生的乙炔气体浓度,为变压器的维护提供技术参数,针对基于DFB激光器的共振型光声光谱技术痕量乙炔气体检测技术开展研究,对传统的光声光谱探测系统进行改进。根据光声光谱技术的理论可知,光声信号的强度与入射激光的功率成正比,所以在光声池的出射窗口采用一个平面反射镜将红外光再次反射到光声池中以增加入射光功率,增强光声信号强度,进一步提高了光声系统的探测灵敏度。通过一定浓度的乙炔气体在不同调制频率和不同调制深度下光声信号强度的变化,确定光声探测系统的最佳调制频率和最佳调制深度为767 Hz和0.3mV。利用不同浓度乙炔气体对系统进行标定,然后采用最小二乘法对光声信号与气体浓度进行拟合,二者具有很好的线性度。通过Allan方差计算可知,系统在平均时间达到200s时,能够达到最低探测极限浓度。实验表明,在一个大气压下,积分时间为10ms时,改进后的共振型光声光谱探测系统对乙炔气体的最低探测极限浓度达到了0.3μL·L~(-1)。还将小波去噪技术引入到低浓度下乙炔气体的光声信号处理中,有效消除了低浓度气体光声信号中的噪声,提高了信噪比。设计的共振型光声光谱探测系统操作简单,最低探测浓度符合国标中对变压器维护过程中对乙炔气体的探测需求,在变压器维护领域具有广阔的应用前景。
[Abstract]:Acetylene gas is a kind of fault gas to judge the operating state of transformer. The concentration of acetylene gas reflects the operating condition of transformer, so it is very important to detect the concentration of acetylene gas in the maintenance of transformer. In order to accurately detect the concentration of acetylene gas produced during transformer operation and provide technical parameters for transformer maintenance, the detection technology of trace acetylene gas based on resonance photoacoustic spectroscopy (RASS) based on DFB laser was studied. The traditional photoacoustic spectrum detection system is improved. According to the theory of photoacoustic spectroscopy, the intensity of the photoacoustic signal is proportional to the power of the incident laser, so the infrared light is reflected into the photoacoustic cell again by a plane reflector in the output window of the photoacoustic cell to increase the incident light power. The detection sensitivity of the photoacoustic system is further improved by enhancing the intensity of the photoacoustic signal. The optimum modulation frequency and modulation depth of the photoacoustic detection system were determined to be 767 Hz and 0.3 MV by the variation of the intensity of the photoacoustic signal at different modulation frequencies and different modulation depths of acetylene gas in a certain concentration. The system was calibrated by acetylene gas with different concentrations, and the photoacoustic signal was fitted with the gas concentration by least square method. The calculation of Allan variance shows that the system can reach the minimum detection limit concentration when the average time reaches 200 s. The experimental results show that the minimum detection limit for acetylene gas is 0.3 渭 L L ~ (-1) for the improved resonance photoacoustic spectrum detection system at one atmospheric pressure and integral time of 10ms. The wavelet denoising technique is also introduced into the photoacoustic signal processing of acetylene gas at low concentration, which effectively eliminates the noise in the low concentration gas photoacoustic signal and improves the signal-to-noise ratio (SNR). The resonant photoacoustic spectrum detection system is simple to operate and the lowest detection concentration is in line with the requirement of acetylene gas detection in the transformer maintenance process in the national standard. It has a broad application prospect in the field of transformer maintenance.
【作者单位】： 中国科学院合肥物质科学研究院安徽光学精密机械研究所;中国科学技术大学;
【基金】：国家自然科学基金项目(41575030,21307136)资助
【分类号】：O657.3;TM407
本文编号：2395584
[Abstract]:Acetylene gas is a kind of fault gas to judge the operating state of transformer. The concentration of acetylene gas reflects the operating condition of transformer, so it is very important to detect the concentration of acetylene gas in the maintenance of transformer. In order to accurately detect the concentration of acetylene gas produced during transformer operation and provide technical parameters for transformer maintenance, the detection technology of trace acetylene gas based on resonance photoacoustic spectroscopy (RASS) based on DFB laser was studied. The traditional photoacoustic spectrum detection system is improved. According to the theory of photoacoustic spectroscopy, the intensity of the photoacoustic signal is proportional to the power of the incident laser, so the infrared light is reflected into the photoacoustic cell again by a plane reflector in the output window of the photoacoustic cell to increase the incident light power. The detection sensitivity of the photoacoustic system is further improved by enhancing the intensity of the photoacoustic signal. The optimum modulation frequency and modulation depth of the photoacoustic detection system were determined to be 767 Hz and 0.3 MV by the variation of the intensity of the photoacoustic signal at different modulation frequencies and different modulation depths of acetylene gas in a certain concentration. The system was calibrated by acetylene gas with different concentrations, and the photoacoustic signal was fitted with the gas concentration by least square method. The calculation of Allan variance shows that the system can reach the minimum detection limit concentration when the average time reaches 200 s. The experimental results show that the minimum detection limit for acetylene gas is 0.3 渭 L L ~ (-1) for the improved resonance photoacoustic spectrum detection system at one atmospheric pressure and integral time of 10ms. The wavelet denoising technique is also introduced into the photoacoustic signal processing of acetylene gas at low concentration, which effectively eliminates the noise in the low concentration gas photoacoustic signal and improves the signal-to-noise ratio (SNR). The resonant photoacoustic spectrum detection system is simple to operate and the lowest detection concentration is in line with the requirement of acetylene gas detection in the transformer maintenance process in the national standard. It has a broad application prospect in the field of transformer maintenance.
【作者单位】： 中国科学院合肥物质科学研究院安徽光学精密机械研究所;中国科学技术大学;
【基金】：国家自然科学基金项目(41575030,21307136)资助
【分类号】：O657.3;TM407
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1 刘斌;蔡解民;;关于乙炔气体浓度检测器安装位置的研究[J];科技创新与应用;2013年33期
，本文编号：2395584
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