Analysis of the characteristics of а cumulant system for liquid leakage detection in pipelines

Abstract

Acoustic noise signals that are generated by fluid leakage due to a leak in the pipeline have in general case non-Gaussian distribution, so for the further development of acoustic contact leak detection together with correlation-spectral methods it is advisable to use methods used for probabilistic analysis of non-Gaussian processes, in particular cumulant methods of noise diagnostics. The principle of cumulant method of liquid leakage detection in pipelines during operation is considered, which is based on the use of cumulants to distinguish acoustic noise signals registered at the control points of the pipeline section, namely on use of the distance between the cumulant vectors of signals and the mutual correlation function of signals. The block diagram of the cumulant system for liquid leakage detection is given. In order to use the cumulant leakage detection system for power plant diagnosis, a layout of the acoustic leak detection system has been developed, which is a hardware-software complex that performs the collection, registration and statistical processing of acoustic noise signals, as a result of which a decision is made on the presence or absence of leakage, the parameters of the hardware part of the system were given. To obtain estimates of the statistical characteristics of real leakage signals, an installation was used that allows to perform physical modeling of fluid leakage in a pipeline in standing water under sustainable conditions, with fixed leak dimensions and pressure level control. Acoustic noise generated by the flow of fluid moving in the heat pipeline is used as interference. Using the statistical characteristics of real signals, the characteristics of the cumulant leakage detection system were determined – leakage signal attenuation; the maximum distance between the transducers at which the leakage is detected; detector sensitivity; the influence of bandpass filtering on these characteristics is investigated. Keywords: acoustic contact leak detection, liquid leakage detector, acoustic noise signals, cumulant analysis