Research on leak location method of water supply pipeline based on negative pressure wave technology and VMD algorithm

Abstract

Noise makes the inflection point of the negative pressure wave (NPW) difficult to be extracted. Therefore, an adaptive denoising method based on VMD (ADM-VMD) is proposed. ADM-VMD uses correlation coefficient to select effective intrinsic mode function (IMF) components, and obtains the optimal denoising signal according to the minimum information entropy. The traditional inflection point extraction method has the defect of poor robustness. Thus, an adaptive inflection point extraction method based on VMD (IPEM-VMD) is proposed. IPEM-VMD selects the optimal detail signal by kurtosis and extracts the inflection point according to the maximum peak. The experimental conditions with two pipe diameters were set up (0.08 m and 0.125 m). The results show that ADM-VMD can effectively smooth the noise and obtain a clear pressure drop curve. IPEM-VMD obtains a unique and clear maximum peak, which has good robustness to small noise. The average positioning error of the proposed method is 6.42%.