NEGATIVE PRESSURE WAVE-BASED LEAK DETECTION AND LOCALIZATION IN LONG GAS PIPELINES

Abstract

Gas pipelines are subjected to leakages and ruptures due to aging, corrosion and human activities even with routine maintenance. A negative pressure wave (NPW)-based detection system is required to be sensitive, robust, reliable, and accurate in the prediction of leakage flow rate and location. However, these requirements are challenging to meet owing to a lack of reliable models for the estimation of the smallest detectable leak, high false alarm rate, and weak robustness of localization algorithms. In order to address the above issues, the first contribution in this thesis is that an efficient and verified non-isothermal model has been introduced to investigate the mechanisms underlying the generation and propagation of NPWs. Secondly, regarding the leak detection, a characterization of leak signals has been proposed for the pipelines that are lacking prior knowledge of leak events. The results show that the proposed characterization is able to discover all leaks in the experiments. Finally, in the estimation of the leak locations, a pre-processing technique has been proposed to remove the undesired information in the leak signals. The proposed technique can enhance the robustness of the leak localization system while optimizing the maximum error to 0.86 %.