Detection of Small Leakage from Pipeline based on Improved Harmonic Wavelet

In detection and localization of leakage from pipeline, as the signal of pressure is usually mixed with noise, the singularity of the negative pressure wave generated by a small leakage can not be accurately extracted by using conventional methods and thus the leakage can not be accurately located. For the above reasons, a practical method based on improved harmonic wavelet was used. This method is to identify small leakage signal. The fine features, the basic principle and the shortcomings of harmonic wavelet were presented. Concerning its shortcomings of poor positioning in the time domain, an improved harmonic wavelet was proposed. And then in order to accurately locate leakages from pipelines, the inflection points of negative pressure waves were accurately extracted by using the improved harmonic wavelet. The experimental results show that the improved harmonic wavelet has improved the capability of positioning in the time domain in order to locate more accurately.