Fuzzy directional residual evaluation for multi leaks in pipelines

This paper introduces a method to locate simultaneous leaks in a pipeline when only the inflow and outflow of the fluid are available. It is assumed that the fluid in the duct with fixed leaks positions can be described by an approximated finite dimensional model considering pressure at the end of the duct as control variables. This model is used to design a vector called residual pattern in steady state for each abnormal condition using a bank of unknown input observers in which each observer is robust to one leak and sensitive to the rest. Using these patterns a fuzzy reasoning is proposed which searches to match the direction of the real time residual vector with one element of the set of abnormal patterns. The performance of the approach is demonstrated using simulated and experimental data taken from a water pilot pipeline of approximate 132 m long and 0.104 m of diameter with flow rate of 12 l/s of water.