Minimal Order Nonlinear Observer for Leak Detection

Abstract

A method for leaks location in a pipeline, using sensors only at the extremes of the line is presented. The detection problem is solved, assuming a nonlinear fluid model of finite dimension with uncertainty in the leak position, and generating the residual with two minimal order nonlinear observers. Flow and pressure data at the beginning and at end of the line are considered as output and input of the system respectively. Since the proposed model satisfies (1) the condition to generate a residual, assuming at the most two leaks, and (2) the strong detectability fault property for each output component, two nonlinear robust filters with respect to a leak are designed to generate the residual. To simplify the residual evaluation and estimate the leak position, a static relationship between each component of the residual and the position error is derived. The main contribution of this paper is to take advantage of the residual equation with uncertainty to isolate a fault. The effectiveness of this approach is shown by a comparison with the practical method reported in [1] using results obtained from simulated and experimental data of a water pilot pipeline of 132 m long, with a diameter of 0.1 m and with a flow rate of 12 l/s.

Leak Detection, Size Estimation and Localization in Pipe Flows

“…This is important, because it removes the need for recomputing the bank of observers when the operating point of the pipeline is changed. In [6], a nonlinear version was proposed, using an extremely coarse discretization grid. The detection method presented in [3], [6], using a bank of observers, can potentially detect multiple leaks.…”

“…In [6], a nonlinear version was proposed, using an extremely coarse discretization grid. The detection method presented in [3], [6], using a bank of observers, can potentially detect multiple leaks. However, multiple simultaneous leaks is an unlikely event, so the complex structure of a bank of N observers seems unnecessary.…”

DSP application of a water-leak detection and isolation algorithm

“…[3], [4], [5], [6]), but to our knowledge, none of them are focused on a DSP on-line implementation. Besides, when a LDIA is tested with a software representing a pipeline (simulator), normally it gives very nice results, but when the LDIA is fed with measurements from a real pipeline, the results can be far from the expected ones, since neglected phenomena are presented.…”

Comparison of two Detection Algorithms for Pipeline Leaks

“…In the works of Benkherouf et al [3] and Kowalczuk and Gunawickrama [4], [5], leak location is carried on by using a Kalman filter. Works focused to detect two leaks are found in [6]- [8].…”