为满足油浸式变压器在线监测的需求,根据非共振光声光谱和无孔膜油气分离理论,将直径为40 mm的聚全氟乙丙烯(FEP)高分子膜与体积仅为0.3 mL的光声气室结合,设计了集成光声气体传感器和油气分离膜的微型传感模块,该模块具有体积小、油气分离时间短及可实时在线检测的优点。油中溶解的故障特征气体扩散进入气室中,利用近红外激光光声光谱技术、波长调制和二次谐波检测技术对气室中的气体进行高灵敏度检测。对特征气体C2H2检测的实验结果表明,在油温为60 ℃时,油中溶解气体传感系统可在3 h内实现油气分离平衡,其中对于体积分数为10 -6的油中溶解C2H2气体的体积分数测量误差在±30%之内。

Based on the non-resonant photoacoustic spectroscopy and the non-porous membrane oil-gas separation theory, we design a miniature detection module by integrating a photoacoustic gas sensor with an oil-gas separation membrane to satisfy the demand for online monitoring of the oil-immersed power transformer. This design can be realized by combining a polytetrafluoroethylene propylene (FEP) polymer membrane with a diameter of 40 mm with a photoacoustic chamber with a volume of only 0.3 mL. The designed module exhibits a small size, short oil-gas separation time, and real-time online detection. When the fault characteristic gas dissolved in the oil diffuses into the gas chamber, the techniques such as near-infrared laser photoacoustic spectroscopy, wavelength modulation, and second-harmonic detection are used to achieve high-sensitivity gas detection. The experimental detection results of the characteristic C₂H₂ gas prove that an oil-gas separation balance in the oil sensing system with dissolved gas can be realized within 3 h at an oil temperature of 60 ℃. Furthermore, the measurement error is within ±30% for the C₂H₂ gas dissolved in oil with a volume fraction of 10 ^-6.