光声光谱技术在多组分气体浓度探测中的应用
发布时间：2018-10-05 08:01
【摘要】：CO和CH_4气体作为判断变压器运行状态的故障气体,对其浓度的探测在变压器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CH_4和CO气体浓度,本文利用光声光谱技术,设计了一套基于宽带光源的多组分气体探测系统,和共振型光声系统相比,该系统中所用的非共振型光声池体积小,易加工,池内各处信号强度相同,降低了对声学信号探测器的安装要求.系统的性能通过对CO和CH_4气体的探测进行评估.首先,从理论上分析了信号强度与调制频率呈反比,然后根据宽带光声系统在不同调制频率下的响应,确定系统的最佳调制频率为22 Hz.在最佳调制频率下,根据温度与待测气体光声信号的关系,对光声信号进行温度补偿,消除温度变化对光声信号的影响,进一步提高了系统的稳定性.最后,通过不同浓度的CH_4和CO气体对系统进行标定.实验表明,温度补偿前后,光声信号随温度的漂移分别为0.023 23V/℃和8.383 48×10~(-5) V/℃,通过对不同浓度CH_4和CO气体的探测,系统的线性度分别达到0.995和0.998 4.在一个大气压下,积分时间为1s时,宽带光声探测系统对CO和CH_4气体的探测极限浓度能够达到1μL/L.该系统成本低,线性度好,探测灵敏度符合国标对变压器维护过程中CO和CH_4气体的探测要求.
[Abstract]:CO and CH_4 gas are used as fault gases to judge the operating state of transformers. The detection of their concentration is of great significance in transformer maintenance. In order to accurately detect the concentration of CH_4 and CO in transformer operation, a multi-component gas detection system based on broadband light source is designed by using photoacoustic spectroscopy, which is compared with the resonant photoacoustic system. The non-resonant photoacoustic cell used in this system is small in size, easy to process and has the same signal intensity in various parts of the cell, which reduces the installation requirement of acoustic signal detector. The performance of the system is evaluated by the detection of CO and CH_4 gases. Firstly, the inverse ratio between signal intensity and modulation frequency is analyzed theoretically. Then, according to the response of broadband photoacoustic system at different modulation frequencies, the optimal modulation frequency of the system is determined to be 22 Hz.. According to the relation between temperature and gas photoacoustic signal, the temperature compensation of photoacoustic signal is carried out under the optimum modulation frequency, and the influence of temperature change on photoacoustic signal is eliminated, and the stability of the system is further improved. Finally, the system was calibrated with different concentrations of CH_4 and CO gases. The experimental results show that the shift of photoacoustic signal with temperature is 0.023 23V/ 鈩，
本文编号：2252616
[Abstract]:CO and CH_4 gas are used as fault gases to judge the operating state of transformers. The detection of their concentration is of great significance in transformer maintenance. In order to accurately detect the concentration of CH_4 and CO in transformer operation, a multi-component gas detection system based on broadband light source is designed by using photoacoustic spectroscopy, which is compared with the resonant photoacoustic system. The non-resonant photoacoustic cell used in this system is small in size, easy to process and has the same signal intensity in various parts of the cell, which reduces the installation requirement of acoustic signal detector. The performance of the system is evaluated by the detection of CO and CH_4 gases. Firstly, the inverse ratio between signal intensity and modulation frequency is analyzed theoretically. Then, according to the response of broadband photoacoustic system at different modulation frequencies, the optimal modulation frequency of the system is determined to be 22 Hz.. According to the relation between temperature and gas photoacoustic signal, the temperature compensation of photoacoustic signal is carried out under the optimum modulation frequency, and the influence of temperature change on photoacoustic signal is eliminated, and the stability of the system is further improved. Finally, the system was calibrated with different concentrations of CH_4 and CO gases. The experimental results show that the shift of photoacoustic signal with temperature is 0.023 23V/ 鈩，
本文编号：2252616
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