Leak localisation method using a detailed hydraulic model combined with high resolution pressure sensors applied to a real network

Abstract

The objective has been the elaboration of a method of locating specific and background leaks in hydraulic models. We have worked with high-resolution hydraulic models with high resolution pressure sensors. The method has been applied to a real network. To execute an agile adjustment of the models, it is essential to link the hydraulic model with the data of the SCADA. The tool developed by the GISWATER ASSOCIATION, QGIS on POSGRESQL allows exporting networks to EPANET with the demanded resolution. This Work has used three levels of definition regarding the nodes introduced. As instrumentation, three pressure sensors have been used with a resolution of 1 centimetre. The situation of sensors in the network has been defined by using algorithms based on the sensitivity matrix. Background leakage has been modelled using EPANET emitter coefficients. The value of these coefficients has been calculated based on the overall performance of the sector. They have been calculated individually for each node weighted by the lengths of the pipes linking to each node. The combination of a network with a high density of nodes, a distribution of background leakage balancing the emitting coefficients has allowed to adjust the model with errors in the pressures in the three control nodes of the order of 17 centimetres. A previous macrocalibration phase was required because the sensitivity of the model became high enough to detect the existence of a tank that had not been considered due to its little effects. To obtain the flow attributed to punctual leak, a fictional reservoir has been used to subsequently calculate the most likely area where it is located from a thorough search on all nodes. At points where the leak situation is most likely, the average error of the three pressure sensors has been below 11.5 cm