变压器油中溶解乙炔光热干涉检测系统的温度和压强特性

Temperature and pressure characteristics of dissolved acetylene in transformer oilbased on photothermal interference detection system

光热干涉(photothermal interference,PTI)法是一种气体检测的新型光学方法,因其高灵敏度、高精度和“零背景”的优点,有望在油中溶解气体分析(dissolved gas analysis,DGA)检测领域中得以推广和应用。然而,油中溶解气体的温度和压强对光热相位的影响规律尚不明确,为提高PTI技术在DGA领域的适用性,文中提出一种基于Herriott气室的光强调制型PTI油中乙炔传感方案。为模拟故障状态下变压器油中气体检测,文中对含乙炔等多组分特征气体的混合气体进行实测,并重点研究测量过程中温度和压强对检测结果的影响规律,得出温度降低和压强增大均会使光热相位增大。由此表明,乙炔检测的精度和稳定性依赖于检测过程中合理设置温度和压强。所研制的测量系统对乙炔浓度具有较强的线性响应,检测灵敏度为0.151 mV/(μL·L^(-1)),检测下限为5.3μL/L。所提方案为后续开发基于PTI技术的新型DGA检测提供了思路并奠定了基础。

Photothermal interference(PTI)is a new optical method for gas detection.Due to its high sensitivity,high accuracy,and"zero background"advantages,it is expected to be promoted and applied in the field of dissolved gas analysis(DGA).However,the influence of the temperature and pressure of dissolved gases in oil on the photothermal phase is not yet clear.To improve the applicability of PTI technology in the DGA,an intensity-modulated-PTI-based acetylene sensing scheme using a Herriott cell is proposed.Experimental measurements are conducted on mixed gases containing acetylene and other characteristic gases to simulate fault conditions in transformer oil,and the influence of temperature and pressure on the detection results during the measurement process is focused.It is found that the photothermal phase increases with decreasing temperature or increasing pressure.Therefore,the accuracy and stability of acetylene detection depend on the reasonable setting of temperature and pressure during the detection process.The system demonstrates a strong linear relationship with acetylene concentration,with a detection sensitivity of 0.151 mV/(μL·L^(-1))and a detection lower limit of 5.3μL/L.The proposed solution provides insights and lays the foundation for the future development of a new type of DGA based on PTI technology.