Fault Detection and Isolation of Rain Gauges and Limnimeters of Barcelona's Sewer System Using Interval Models

Abstract

In this paper, fault detection and isolation of rain gauges and limnimeters (water level sensors in the sewers) of Barcelona's urban sewer system is presented. The Barcelona urban drainage network has a telemetry network containing 22 rain gauges and more than 100 limnimeters used for the control system. In order to detect and isolate faulty instruments and to reconstruct faulty measurements from data fusion, a fault diagnosis system is necessary. The proposed fault diagnosis strategy is based on building an interval linear model for every instrument (Puig, 2002). Then, while the real measure is inside the interval of predicted behaviour (or envelope) generated using its interval model no fault can be indicated. However, when the measure is outside its envelope a fault can be indicated. Fault isolation is based on the matching of the real fault signature with the theoretical fault signature using structured residuals (Gertler, 1998).