小波模极大值法在天然气管道检漏的应用

Application of Wavelet Transform Modulus Maximum in Leakage Detection of Natural Gas Pipeline

天然气管道泄漏引起的负压波传播到检测点时,会使压力信号发生突变。受很多干扰因素的影响,采集到的压力波信号含有大量噪声,利用小波变换中的模极大值法对信号进行变换,能准确提取信号特征点——压力信号奇异点,检测出负压波到达两端传感器的时间差,结合传播速度就可以进行泄漏点定位。

The pressure signal changes suddenly when the negative pressure wave induced by gas leakage from natural gas pipeline propagates to the monitoring point. Due to the influence of many interference factors, the collected pressure wave signal contains much noise. Transforming the signal by the modulus maximum in wavelet transform can exactly extract the signal character that is the singularity of pressure signal, and detect the time difference of reaching the sensors at the ends by the negative pressure wave. The leakage point can be located, combined with the propagation velocity.