On the design of a nonlinear state observer for the location of a blockage in a pipeline

RUBIO SCOLA, IGNACIO; BESANÇON, GILDAS; GEORGES, DIDIER; GUILLÉN, MARCOS; DULHOSTE, JEAN FRANÇOIS; SANTOS RAFAEL

Isla Margarita

Congreso; XII International Congress on Numerical Methods in Engineering and Applied Sciences; 2014

This paper presents a design of a nonlinear state observer in order to locate a blockage in a pipeline, by only using measurements at each end. First, a mathematical model of the pipeline is presented, using the water hammer equations and applying the finite difference method for the solution with n sections. Then, based on the experience got from the problem of leak location with nonlinear observers, a second mathematical model is obtained by discretization in only two sections, and a nonlinear state observer is built. In this new model, the blockage is at the beginning of the second section of the pipeline, whose position is to be estimated by the observer. By analysis of the model, it is found that in order to make this location estimation possible, the observer requires specific inputs, called persistent inputs. These persistent inputs are found empirically, and numerical simulations are presented with the proposed state observer and mathematical model, showing a satisfactory blockage location. Simulations where measurements are subject to Gaussian white noise are also included.