Negative pressure wave denoising based on VMD and its application in pipeline leak location

When negative pressure wave (NPW) signals are used to locate pipeline leaks, noise will increase the error of location estimation. Thus, an adaptive noise reduction method based on variational mode decomposition (ANR-VMD) is proposed to improve the accuracy of leak location. First, the number of decomposition layer of VMD is optimized by the minimum information entropy. Second, the effective intrinsic mode function components are selected using the correlation coefficient. Finally, these components are reconstructed to obtain the denoised signal. In real experiments, ANR-VMD obtains a smoother pressure signal, retains the signal waveform characteristics, and identifies evident NPW inflexion point. The location accuracy of ANR-VMD for six leak points is verified. The minimum positioning error of the wavelet and EMD methods is 3.51 %, and the leakage cannot be located when the error is high. The minimum error of ANR-VMD is 0.9 %, and the maximum is 3.75 %.