Transient-based periodical pipeline leak diagnosis

Abstract

In this paper, a periodical pipeline leak diagnosis technique based on transient response difference monitoring is presented. During past two decades, a considerable amount of research effort has been dedicated to the application of controlled hydraulic transients for pipe leak detection and location. Leak reflection method (LRM) and inverse transient analysis (ITA) are the most popular techniques described in the literature. Significant improvements of the theoretical part of the two methods have been presented. However, available experimental results indicate that both LRM and ITA approaches suffer from model precision-related errors. As a result, only large leaks can be detected and located. The fundamental principle of the proposed methodology is the assumption that leak diagnosis will be performed periodically. Leakage detection is considered to be a repetitive procedure that is a part of the active failure monitoring system, which is permanently installed on the pipeline. The technique does not use a numerical model of a pipeline to detect and locate leaks and, therefore, eliminates the model-related errors. A transient response of the pipeline system is measured periodically and the difference between transient responses is monitored to identify the presence of a leak/leaks. Leaks of a relatively small size can be successfully detected and located. The performance of the proposed method was evaluated on the real large water transmission pipeline and positive results were observed. The lower limit of the detectable leak diameter was estimated to be as small as 0.31% of the pipeline diameter. The observed precision of the derived leak location was less than 0.3% of the total pipeline length. Proposed periodical leak diagnosis system allows for a quick and inexpensive leak detection and location in water transmission mains. The technique is also able to detect and locate other pipeline abnormalities, such as blockages and air pockets. The approach can be installed separately or be integrated with the continuous burst monitoring technique that was earlier developed by the authors to form a multi-type pipeline failure detection and location system. Copyright ASCE 2006.