Rainfall-runoff multi-modelling for sensor fault diagnosis

In view of the limitations of flood and pollution prevention in urban sewage networks, the control of hydraulic equipment now calls for more reliable measurements provided by different sensors. The sensor fault detection and isolation described here requires the availability of a rainfall-runoff relationship in order to apply analytical redundancy-based diagnostic procedures. However, because this relationship is conspicuously non-linear and time varying, the latter relationship is identified by using a multi-model approach. The proposed modelling approach has been successfully tested on a watershed located in an urban area of Nancy, in eastern France, using actual rainfall and runoff data taken from the sewerage control centre database. The model obtained is then used to increase the degree of information redundancy in order to implement a sensor fault diagnostic procedure. Since no statistical hypothesis on measurement uncertainties can be made, interval arithmetic is used to derive residual tolerance. (C) 2001 Elsevier Science Ltd. All rights reserved.