Leak detection and location in liquid pipelines by analyzing the first transient pressure wave with unsteady friction

A new leak detection method is proposed here which is based on the cepstrum of the cross-correlation of the pressure signals from two transducers. Computational simulations of leaks with different properties, size, position and shape, in a straight pipe and a T-Junction network were studied. The proposed method was successful in estimating leakages and the pipeline features with a high precision. For the results with a straight pipe, this method is considerably more accurate than using the cross-correlation leak detection method or the cepstrum method alone. However, the results obtained by cepstrum and cepstrum of cross-correlation for the T-Junction case were quite accurate, while cepstrum alone showed a slightly better precision.

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State of Research on Negative Pressure Techniques Applied to Leak Detection in Liquid Pipelines

2004 International Pipeline Conference, Volumes 1, 2, and 3 ◽

10.1115/ipc2004-0621 ◽

2004 ◽

Cited By ~ 1

Author(s):

Wei Liang ◽

Lai-bin Zhang ◽

Zhao-hui Wang

Keyword(s):

Pressure Wave ◽

Analytical Techniques ◽

Leak Detection ◽

Point Of View ◽

Detection Methods ◽

Propagation Mechanism ◽

Detection Techniques ◽

Wave Detection ◽

State Of Research ◽

Signal Processing Methods

In China, the rarefaction-pressure wave techniques are widely used to diagnose the leakage fault for liquid pipelines. Many leaking propagating assumptions, such as stable single-phased flow hypothesis and none rarefaction wave front hypothesis, are often uncertain in the process of leak detection, which can easily result in some errors. Thus the rarefaction-pressure wave techniques should be integrated with other analytical techniques to compute a more accurate leak location. Additionally, the development trends of rarefaction-pressure wave techniques lie in three aspects. First, rarefaction-pressure wave detection techniques will be integrated with other compatible detection techniques and modern signal processing methods to solve the complex problems encountered in leak detection. Second, studies of rarefaction-pressure wave techniques have advanced to a new stage. The deductions on propagation mechanism of rarefaction-pressure wave have been successfully applied to determine leaks qualitatively. Third, analysis on rarefaction-pressure wave detection techniques will be made from a quantitative point of view. The quantitative data have been used to deduce leak amounts and location. The purpose of this paper is to present the recent achievements in the study of improved rarefaction-pressure wave detection techniques. The rarefaction-pressure wave detection methods, effects of incomplete information conditions, the improvements of rarefaction-pressure wave detection techniques with modified factors and propagation mechanisms are comprehensively investigated. The disfigurements of rarefaction-pressure wave are analyzed. The corresponding methods for resolving such problems as ill diagnostic information and weak amplitude values are put forward. Several methods for stronger small leakage detection ability, higher leakage positioning precision, lower false alarm rates are proposed. The application of rarefaction-pressure wave detection techniques to safety protection of liquid pipelines is also introduced. Finally, the prospect of rarefaction-pressure wave detection techniques is predicted.

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Benchmarking the Dual and Compound Techniques-Based Branching Design Strategy Used for Upgrading of Pressurized Hydraulic Systems

Journal of Pressure Vessel Technology ◽

10.1115/1.4049875 ◽

2021 ◽

Vol 143 (2) ◽

Author(s):

Waêl Ben Amira ◽

Ali Triki

Keyword(s):

Pressure Wave ◽

Plastic Material ◽

Conventional Technique ◽

Steel Pipe ◽

Low Density Polyethylene ◽

Piping System ◽

Low Density ◽

Hydraulic Systems ◽

Transient Pressure ◽

Pipe Flow Model

Abstract Prior research has recognized that the compound- and dual-technique-based branching redesign measures, used as alternatives to the conventional technique-based one, were effective in upgrading steel pipe-based pressurized hydraulic systems. Principally, the compound technique used two different plastic material types for the short-penstock instead of the single material type utilized in the conventional technique. However, the dual technique is based on splitting the single penstock installed in the conventional technique into a set of dual subpenstocks placed at each connection of the main-piping system to hydraulic parts. This handling aimed at improving the conventional technique efficiency with regard to the tradeoff between the magnitude attenuation and period expansion effects of the transient pressure-wave signal. Accordingly, this study proposed a comprehensive comparison between the compound- and dual-technique-based branching strategy with particular focus on the tradeoff between the two last parameters. The plastic material types demonstrated in this study included the high- or low-density polyethylene. The application addressed a waterhammer maneuver initiated into a reservoir-steel-pipe-valve system. Numerical computations used the method of characteristics for the discretization of the 1D extended pressurized-pipe flow model, embedding the Kelvin–Voigt and Vitkovsky formulations. The finding of this study suggested that the high- or low-density polyethylene (HDPE–LDPE) setup of the compound technique is the most prominent protected system setup, providing an acceptable tradeoff between the attenuation of magnitude and the expansion of the period of pressure-wave oscillation.

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Leak Detection Method Based on Pressure Wave Change

Volume 3: Materials and Joining; Pipeline Automation and Measurement; Risk and Reliability, Parts A and B ◽

10.1115/ipc2006-10071 ◽

2006 ◽

Cited By ~ 1

Author(s):

XianYong Qin ◽

LaiBin Zhang ◽

ZhaoHui Wang ◽

Wei Liang

Keyword(s):

Pressure Wave ◽

Detection System ◽

Sudden Change ◽

Leak Detection ◽

Special Focus ◽

Oil Pipeline ◽

Scada System ◽

Wave Change ◽

Ole For Process Control ◽

Pipeline Pressure

Reliability, sensitivity and detecting time under practical operational conditions are the most important parameters of a leak detection system. With the development of hardware and software, more and more pipelines are installed with advanced SCADA (Supervisory Control and Data Acquisition) system, so the compatibility of the leak detection system with SCADA system is also becoming important today. Pipeline leakage generates a sudden change in the pipeline pressure and flow. The paper introduces leak detecting methods according to the pipeline pressure wave change. In order to improve the compatibility of the leak detecting system, “OPC (Ole for process Control)” technology is used for obtaining the pressure signals from the distributed data collection system. Special focus is given on analysis of the pressure signals. It is successful to denoise the signals by means of wavelet scale shrinkage, and to capture the leak time tag using wavelet transform modulus maximum for locating the leak position accurately. A leak detecting system is established based on SCADA system. Tests and practical applications show that it locates leak position precisely. Good performance is obtained on both crude oil pipeline and product pipeline.

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