An acoustic emission based multi-level approach to buried gas pipeline leakage localization

Abstract

Precisely localizing a leakage source in a buried pipeline is of great importance for decision making on emergence response of gas leakage accident. As an effective leakage localization method, acoustic emission (AE) has received much attention in recent years. However, the application of AE for leakage localization in long-range or buried pipeline is greatly limited due to the conflict between the accuracy of testing results and the efficiency of testing works. To further improve the applicability of AE technique for long-range pipeline, a novel leakage localization approach is proposed based on the multi-level framework. The approach is consisted of two steps: regional localization and precise localization. The regional localization is to determine the region of the leakage source based on the signal attenuation characteristics, and then the precise localization results are obtained by the cross-correlation analysis of wavelet packet decomposition (WPD) components based on the region of leakage source. Experiments were conducted on a buried pipeline with a continuous leakage source and a linear array of two sensors was positioned in two sides of the leakage source. To study the feasibility of the proposed approach, a series of in-situ tests were carried out by changing the source-sensor distance. The results indicate that the accuracy of regional localization is 100% and the maximum error percentage of precise localization is 5.3% under varying sensors distances from 10 to 33 m. The proposed leakage localization method provides a promising way to locate the leakage source in long-range pipeline by using AE technique because it can achieve a better balance between accuracy and efficiency.