光聲光譜技術在多組分氣體濃度探測中的應用
發(fā)布時間：2018-10-05 08:01
【摘要】：CO和CH_4氣體作為判斷變壓器運行狀態(tài)的故障氣體,對其濃度的探測在變壓器維護中具有重要意義.為了準確探測變壓器運行過程中產生的CH_4和CO氣體濃度,本文利用光聲光譜技術,設計了一套基于寬帶光源的多組分氣體探測系統(tǒng),和共振型光聲系統(tǒng)相比,該系統(tǒng)中所用的非共振型光聲池體積小,易加工,池內各處信號強度相同,降低了對聲學信號探測器的安裝要求.系統(tǒng)的性能通過對CO和CH_4氣體的探測進行評估.首先,從理論上分析了信號強度與調制頻率呈反比,然后根據(jù)寬帶光聲系統(tǒng)在不同調制頻率下的響應,確定系統(tǒng)的最佳調制頻率為22 Hz.在最佳調制頻率下,根據(jù)溫度與待測氣體光聲信號的關系,對光聲信號進行溫度補償,消除溫度變化對光聲信號的影響,進一步提高了系統(tǒng)的穩(wěn)定性.最后,通過不同濃度的CH_4和CO氣體對系統(tǒng)進行標定.實驗表明,溫度補償前后,光聲信號隨溫度的漂移分別為0.023 23V/℃和8.383 48×10~(-5) V/℃,通過對不同濃度CH_4和CO氣體的探測,系統(tǒng)的線性度分別達到0.995和0.998 4.在一個大氣壓下,積分時間為1s時,寬帶光聲探測系統(tǒng)對CO和CH_4氣體的探測極限濃度能夠達到1μL/L.該系統(tǒng)成本低,線性度好,探測靈敏度符合國標對變壓器維護過程中CO和CH_4氣體的探測要求.
[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，
本文編號：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，
本文編號：2252616
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