分布式激光甲烷检测系统振动干扰诊断与辨识

Diagnosis and recognition of vibration interference in distributed laser methane detection system

为消除外界振动对分布式激光甲烷检测系统的影响,在分析振动对光纤物理特性及甲烷检测的影响、振动波形频率特征的基础上,提出一种基于实时采样信号和设定频率信号的振动波形辨识算法。该算法通过傅里叶变换、互相关运算、最大相似系数判定和甲烷浓度解算等步骤,有效识别出不同频率的外界振动波形,进而可准确删除振动波形,消除外界振动对甲烷浓度测量值的影响。实验室测试及工业性测试结果表明,该算法能有效识别出不同频率的振动干扰,避免振动信号引入的测量误差。

In order to eliminate influences of external vibration on distributed laser methane detection system,based on analysis of frequency characteristics of vibration waveform and influences of vibration on physical properties of fiber and methane detection,a vibration waveform recognition algorithm based on real-time sampling signal and set frequency signal was proposed.The algorithm can effectively identify external vibration waveforms with different frequencies by steps including Fourier transform,crosscorrelation operation,maximum similarity coefficient judgment and methane concentration calculation,and then the vibration waveform can be accurately deleted and the influences of external vibration on methane concentration measurement can be eliminated.The laboratory test and industrial test results show that the algorithm can effectively identify the vibration interference with different frequencies and avoid measurement error introduced by vibration signal.