Pressure sensor distribution for leak detection in Barcelona water distribution network R. Pe ´ rez, V. Puig, J. Pascual, A. Peralta, E. Landeros and Ll. Jordanas ABSTRACT R. Pe ´ rez V. Puig J. Pascual Automatic Control Department Technical University of Catalonia, Rambla Sant Nebridi, 10, 08222 Terrassa, Spain E-mail: vicenc.puig@upc.edu A. Peralta Ll. Jordanas AGBAR, Torre Agbar, Av. Diagonal, 21108018 Barcelona, Spain E. Landeros CETaqua, Campus Norte de la UPC, Passeig dels Tillers, 3, 08034 Barcelona, Spain This paper proposes a leakage detection method based on detecting significant discrepancies between pressure measurements and their estimations obtained from the simulation of a calibrated water distribution network model. Every sensor in the network will allow to detect a discrepancy in pressure due to leakage depending on its location. Then, a set of well distributed pressure sensors will generate a leakage signature that allows leakage localisation. This paper presents the methodology used in the Barcelona network for distributing properly the sensors for a good discrimination in the leakage localisation process. The methodology for sensor placement uses the pressure sensitivity matrix to the leakage presence. This matrix is normalised and binarised in order to be used as a leakage signature matrix using the standard model based fault diagnosis approach. Sensors may be installed in any node and leakages are simulated as a constant demand that can appear in any node too. The problem of deciding which are the best localisations for a small number of sensors in order to detect and localise leakages is an inverse problem that should be solved using optimisation. The resulting optimisation problem is of discrete nature and very huge for a real network. This type of problem is, in general, hard to solve and very time consuming. The use of GA (Genetic Algorithms) has been proved adequate according to the formulation of the signatures in the sensitivity matrix. Key words | leakage localisation, sensitivity matrix, sensor placement, water networks INTRODUCTION Water loss in distribution system networks is an issue of a great concern for water utilities, strongly linked with operational costs and water resources savings. Continuous improvements on water losses management are being applied and new technologies are developed to achieve higher levels of efficiency. Usually a leakage detection method in a DMA (District Metered Areas (McDonald 2005)) starts analysing input flow data, such as minimum night flows and consumer metering data. Once the water distribution district is identified to have a leakage, tech- niques are used to locate the leakage for pipe replacement or repairing. The whole process could take weeks or months with an important volume of water wasted (Farley & Trow 2003). In this context, Aigu ¨ es de Barcelona (Agbar), the drinking water company in Barcelona and part of Agbar Group, is continuously developing and implementing methodologies to reduce leakages, minimize detection time and resources involved. A methodology to detect and pre-localize leaks is developed within a project carried out by Aguas Barcelona, Water Technological Centre CETaqua, and Technical University of Catalonia (UPC) (Landeros et al. 2009). The objective of this project is to develop and apply an efficient system to detect and locate leaks in a water distribution network. It integrates methods and technologies available being used by water companies, including DMA and flow/pressure sensor data, in conjunc- tion with mathematical hydraulic models. doi: 10.2166/ws.2009.372 715 Q IWA Publishing 2009 Water Science & Technology: Water Supply—WSTWS | 9.6 | 2009