Multi-leak detection with wavelet analysis of pressure sensitivities in water distribution networks.

Leak detection becomes an important issue for managers of water supply networks. They need to detect quickly all the unexpected events that could occur in the network, such as leakages, damage, or sensor malfunction. The cost of water is increasing; therefore loss of water by leaks must be reduced because damages are often expensive. In most water distribution networks, a large percentage of water is lost in transit from treatments units to consumers. Around 25% of production is lost or unaccounted due to several causes but mainly leakages, false measurements errors, public usage such as fire-fighting, earthquakes and sometimes severely cold weather. Most of the research until now proposes several methods for leak detection, considering only one leak in the system. In this work, detection of several leaks is proposed, using an extended horizon analysis of pressure sensitivities. The proposed method is a combination of different detection methods, such as pressure sensitivities matrix, wavelet analysis, phase-quadrant demodulation code, and finally a weighting and voting system. This approach is tested in simulations for two different networks; a network with high consumption, Hanoi network, and a larger network, Quebra. Simulation results showed that in presence of two leaks, the detection of these two leaks is around 80%, detecting the leak node or one of the neighbors nodes around, and of 95% detecting the leak node or the second order neighbors nodes, being these the neighbors of the neighbors; in presence of three leaks, the detection of the three leaks is around 97% detecting the leak node or the second order neighbors nodes. Extensive simulations were realized for each of the water networks to validate the algorithm performance.