Two leaks isolation in a pipeline by transient response

This paper presents a method for the identification of two leaks in a pressurized single pipeline where both transient and static behavior of the fluid in leaks conditions are used to identify the parameters associated to the leaks without requirements of valve perturbation. The procedure is based on a family of lumped parameters nonlinear models with same steady state behavior in leaks condition and parameterized in terms of a known parameter zeq assuming only pressure and flow rate measurements at the extremes of the line. This model is derived discretizing only the space variable. The key of the method is the automatic selection of the specific family of models to be identified using the steady state conditions produced by the leaks. This fact reduces the research interval and the number of unknown parameters simplifying the minimization issue of the error between model and measured data. Considering this family an algorithm combining transient and steady state measurements is presented. The potential of the technique and its robustness with respect to operation point changes after the leaks occurrence are illustrated by simulation using the parameters of a water pilot pipeline of 135 m long installed at the UNAM in which the norm of the upstream and downstream flow error is minimized.