Leakage Locating in Underground High Pressure Gas Pipe by Acoustic Emission Method

• Published in: Journal of nondestructive evaluation Vol. 32; no. 2; pp. 113 - 123
• Main Authors: Mostafapour, A., Davoodi, S.
• Format: Journal Article
• Language: English
• Published: New York Springer-Verlag 01.06.2013
• Subjects: Acoustic emission; Algorithms; Characterization and Evaluation of Materials; Classical Mechanics; Control; Dynamical Systems; Engineering; Filtering; Filtration; Gas pipelines; Leakage; Natural gas; Solid Mechanics; Vibration; Wavelet transforms; Acoustic emission; Wavelet transform; Cross-correlation; Urban gas pipe
• ISSN: 0195-9298; 1573-4862
• DOI: 10.1007/s10921-012-0158-4

Detecting gas leakage accurately in urban high-pressure natural gas pipelines is a great problem all over the world. Gas leakage may lead to pollution and severe environmental damages; therefore, in order to minimize the leakage problem, it is necessary to maintain pipelines. Acoustic emission is a technique to detect leakage in urban pipelines. Leakage in high-pressure pipes radiates acoustic emission signals that are transferred through the pipe walls. This paper proposes a leakage detection algorithm combined with wavelet transform, filtering and cross-correlation techniques to locate leakage source in urban gas pipes. The major noise of acoustic emission signals is removed through the wavelet transform and filtering technique. After removing the noise, the time difference between the signals recorded at two sensors is precisely computed using cross-correlation function. Experiments are carried out with continuous leakage source and a linear array of two sensors positioned in two sides of the leakage source. To study the accuracy of the proposed algorithm, several tests were carried out changing the source-sensor distance, and a percentage error less than 5 % was found in the leakage detection.