08.12.2021; Vortrag
Leak Detection and Localization in Noisy Pipelines
Physics department
Aristotle University of Thessaloniki
Many practical applications that involve the transportation of fluid products require the use of pipeline networks. Such networks offer considerable advantages and they are encountered in several different fields. However, a serious problem that emerges in this kind of networks and compromises their safety and normal operation is the occurrence of leaks. Extensive research has been conducted over the years, relative to the development of reliable and efficient leak detection and localization systems, but not so much has been presented about pipelines in high-noise environment.
In this presentation a method for leak monitoring of noisy industrial pipelines is introduced. This method is based on evaluating a set of features extracted from the acquired acoustic signal of a pipeline. Accelerometers are mounted on the external surface of the monitored pipeline for this purpose. The method relies on defining thresholds that are constantly updated based on previously acquired feature values. The algorithm runs in short segments and produces an output based on the current feature
values and their active thresholds. An occurring leak event can introduce a noticeable change in these values and cause them to exceed their specified limits. The algorithm is associated with a set of parameters, that can be defined in such a way that the system can adapt to the noise characteristics of the pipeline.
A leak localization method is also introduced, based on the propagation of acoustic signals in a pipeline when a leak is present. This method employs the use of accelerometers mounted on the external surface of the monitored pipeline, in order to pick up the acoustic – vibrational leak signals. However, another important factor that needs to be considered is the presence of several physical phenomena that take place in a pipeline and affect the creation and propagation of acoustic waves. Such phenomena like the acoustic dispersion, the frequency dependent attenuation and the resonances are studied, based on synthesized signals, and their influence on the leak localization accuracy is discussed.
According to the proposed method, the acquired signals are segmented both in the time and in the frequency domain and a Time-Difference-Of-Arrival (TDOA) algorithm is used for the processing of the leak data. Then, statistical analysis takes place as a final step in the identification of the leak position. The proposed methods were tested experimentally, both in a laboratory setup and in refinery pipelines with high ambient noise, and the results showed that they can detect and localize leaks efficiently.