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文摘
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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CH4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CH4气体的探测要求. |
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其他语种文摘
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CO and CH_4 as the fault gases in transformer, the detection of their concentration has important significant in transformer maintenance. In order to detect CH_4 and CO gas concentration in transformer accurately, a photoaoustic spectroscopy multi-component gas detection system based on broadband thermal radiation light source has been developed. Compared to resonant photoacoustic cell based photoacoustic detection system, the non resonant photoacoustic cell used in the system has the advantage of small volume, easy to processed, high sensitivity and the intensity of signal is the same everywhere in non-resonant photoacoustic cell, thus reduce the requirements for the installation of the detector. The performance of the system was evaluated by detection of CH_4 and CO. First, the relationship of the intensity of photoacoustic signal in non resonant photoacoustic cell between the radius and the modulation frequency was simulated by theoretical, it is illustrated that the signal enhanced with the reduction of the radius and the modulation frequency. Then the optimum modulation frequency of the system was determined as 22 Hz by the response of the system under different modulation frequencies. The function relations of photoacoustic signal and the temperature were studied, then the photocoustic signal was corrected by temperature compensate based on the function of signal and gas temperature under optimum modulation frequency to eliminate the impaction of temperature to photoacoustic signal, the stability of the system was improved after temperature compensate. The drift of the signal to temperature is 0.023 23V/℃ and 8.383 48×10~(-5) V/℃ respectively before and after temperature compensate. At last, the system was calibrated by different concentrations of CH_4 and CO gas, the experiment show that the photoacoustic signal increased with the increasing of gas concentration and the linearity can reach to 0.995 and 0.998 4 respectively for the detection of different concentrations of CH_4 and CO gas. The multi-component gas detection system based on broadband photoacoustic spectroscopy has the sensitivity of 1μL/L for CO and CH_4 detection under atmospheric pressure with the 1s integration time. The developed system has low cost, good linearity and the sensitivity conform to the requirement of national standard in the process of transformer maintenance. |
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来源
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光子学报
,2017,46(6):0612002-1-0612002-6 【核心库】
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DOI
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10.3788/gzxb20174606.0612002
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关键词
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红外光谱
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气体探测
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光声光谱
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甲烷
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一氧化碳
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宽带光源
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温度补偿
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灵敏度
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地址
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中国科学院安徽光学精密机械研究所, 合肥, 230031
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语种
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中文 |
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文献类型
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研究性论文 |
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ISSN
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1004-4213 |
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学科
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电子技术、通信技术 |
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基金
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国家自然科学基金项目
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文献收藏号
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CSCD:6018431
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