• 摘要: 针对气体绝缘设备内故障诊断的需求,设计了一种T型多通光声传感器。传感器结合中心波长为2333.72 nm的近红外激光器,实现了SF6气体绝缘设备中故障特征气体CO的痕量检测。通过优化T型光声池结构并结合多通池,有效延长了光程。实验结果表明,多次反射设计使光声信号强度较单次反射提升14倍,显著提高了检测灵敏度。利用有限元方法仿真分析并测试了气压对系统频率响应的影响,随着气压的升高,光声池的共振频率降低,光声信号幅值增高。在0.4 MPa的高气压环境下,光声信号幅值是0.1 MPa气压下的1.4倍。系统对SF6背景气体下每单位体积分数的CO的检测响应为0.2 μV,最低检测限达到了1.50×10−7

       

      Abstract: A T-type multi-pass photoacoustic sensor was designed for the needs of fault diagnosis within gas-insulated equipment. The sensor, combined with a near-infrared laser with a center wavelength of 2333.72 nm, achieves trace detection of the characteristic fault gas CO in SF6 gas-insulated equipment. The optical path length was effectively extended by optimizing the structure of the T-type photoacoustic cell and combining it with the multi-pass cell. The experimental results show that the multiple reflection design improves the photoacoustic signal intensity by 14 times compared with the single reflection, which significantly improves the detection sensitivity. The effect of gas pressure on the frequency response of the system was analyzed and tested by simulation using the finite element method. With the increase of gas pressure, the resonance frequency of the photoacoustic cell decreases, and the amplitude of the photoacoustic signal increases. The photoacoustic signal amplitude at 0.4 MPa gas pressure shows a 1.4-fold enhancement compared to that at 0.1 MPa gas pressure. The response of the detection system for CO per unit volume fraction under SF6 background gas is 0.2 μV, and the minimum detection limit reaches 1.50×10−7.