Leak-edge detection

Abstract

An edge detection technique is applied herein to improve leak detection for pressurized pipe flow, based on a transient test analysis. The information contained in a signal is interpreted, especially when it is sharp and isolated: The sudden brightness changes an image and the pressure variations due to a pressure wave trespassing the measurement section. Herein, the analogy between edge and leak detections is further developed. After recalling the main characteristics of an edge detection technique based on the wavelet analysis, the application to leak detection in a pipe is presented. The multi-scale product of the wavelet transform is used to detect sharp pressure variations. Both the simplicity and the reliability of this technique as compared to others make it suitable to develop a rational and automatic procedure. Both numerical and experimental pressure signals were used to evaluate the effects of the noise and the test conditions. It is demonstrated that the wavelet analysis of numerical signals facilitates to recognize small step variations, i.e. small leaks, using low cost transducers. The experimental tests corroborate the numerical results.

Keywords:

• Hydraulic transients
• leakage
• water pipelines
• water resources
• wavelets