Les réseaux de distribution d’eau consistent en de grandes infrastructures réparties dans l’espace qui assurent la distribution d’eau potable en quantité et en qualité suffisantes. Les modèles mathématiques de ces systèmes sont caractérisés par un grand nombre de variables d’état et de paramètres dont la plupart sont incertains. Les temps de calcul peuvent s’avérer conséquents pour les réseaux de taille importante et la propagation d’incertitude par des méthodes de Monte Carlo. Par conséquent, les deux principaux objectifs de cette thèse sont l’étude des techniques de modélisation à ordre réduit par projection ainsi que la propagation spectrale des incertitudes des paramètres. La thèse donne tout d’abord un aperçu des méthodes mathématiques utilisées. Ensuite, les équations permanentes des réseaux hydrauliques sont présentées et une nouvelle méthode de calcul des sensibilités est dérivée sur la base de la méthode adjointe. Les objectifs spécifiques du développement de modèles d’ordre réduit sont l’application de méthodes basées sur la projection, le développement de stratégies d’échantillonnage adaptatives plus efficaces et l’utilisation de méthodes d’hyper-réduction pour l’évaluation rapide des termes résiduels non linéaires. Pour la propagation des incertitudes, des méthodes spectrales sont introduites dans le modèle hydraulique et un modèle hydraulique intrusif est formulé. Dans le but d’une analyse plus efficace des incertitudes des paramètres, la propagation spectrale est ensuite évaluée sur la base du modèle réduit. Les résultats montrent que les modèles d’ordre réduit basés sur des projections offrent un avantage considérable par rapport à l’effort de calcul. Bien que l’utilisation de l’échantillonnage adaptatif permette une utilisation plus efficace des états système pré-calculés, l’utilisation de méthodes d’hyper-réduction n’a pas permis d’améliorer la charge de calcul. La propagation des incertitudes des paramètres sur la base des méthodes spectrales est comparable aux simulations de Monte Carlo en termes de précision, tout en réduisant considérablement l’effort de calcul. / Water distribution systems are large, spatially distributed infrastructures that ensure the distribution of potable water of sufficient quantity and quality. Mathematical models of these systems are characterized by a large number of state variables and parameter. Two major challenges are given by the time constraints for the solution and the uncertain character of the model parameters. The main objectives of this thesis are thus the investigation of projection based reduced order modelling techniques for the time efficient solution of the hydraulic system as well as the spectral propagation of parameter uncertainties for the improved quantification of uncertainties. The thesis gives an overview of the mathematical methods that are being used. This is followed by the definition and discussion of the hydraulic network model, for which a new method for the derivation of the sensitivities is presented based on the adjoint method. The specific objectives for the development of reduced order models are the application of projection based methods, the development of more efficient adaptive sampling strategies and the use of hyper-reduction methods for the fast evaluation of non-linear residual terms. For the propagation of uncertainties spectral methods are introduced to the hydraulic model and an intrusive hydraulic model is formulated. With the objective of a more efficient analysis of the parameter uncertainties, the spectral propagation is then evaluated on the basis of the reduced model. The results show that projection based reduced order models give a considerable benefit with respect to the computational effort. While the use of adaptive sampling resulted in a more efficient use of pre-calculated system states, the use of hyper-reduction methods could not improve the computational burden and has to be explored further. The propagation of the parameter uncertainties on the basis of the spectral methods is shown to be comparable to Monte Carlo simulations in accuracy, while significantly reducing the computational effort.

Made available in DSpace on 2014-07-29T15:01:49Z (GMT). No. of bitstreams: 1 Dissertacao Maria Eulina.pdf: 268672 bytes, checksum: c0eee8e291e9fdcbef88ed3cb0d6d969 (MD5) Previous issue date: 2008-08-29 / Increasing population united the behaviour of man carefree about the environmental preservation has led to a scarcity of natural resources. A key resource for human survival has been directly affected by these desmazelos, water. Based on this context arises as a commitment to operational excellence of water supply systems, seeking greater efficiency in the establishment of operational rules. To this end, the general objective of this research is to develop a study of water distribution networks model calibration, because it is believed to be the best technique for tracking this problem by adjusting the physical parameters that have changed over time and dictate strategies. This work aims to develop a technique based on the inverse of calibration using GAs as a tool for optimization, using multiple goals: pressure and flow. The parameters adjusted were roughness coefficients and coefficients of losses by leaks. To evaluate the proposed methodology were employed two networks often used in literature. The first network employed is a theoretical system proposed by Tucciarelli (1999) and was used to evaluate the behavior of multiobjectives methods and their parameters. The second network is located in Campo Grande (MS) has been studied by Cheung (2004) and Soares et al. (2004). This example is a real system that had its data measured in situ and presents all the complications inherent in the calibration real problems. The results were very satisfactory, since the optimization multiobjective shown to be able to improve the accuracy of the calibration of the model. / O aumento populacional unido ao comportamento despreocupado do homem quanto à preservação ambiental levou a uma escassez dos recursos naturais. Um recurso fundamental à sobrevivência humana está sendo diretamente afetado por esses desmazelos, a água. Com base nesse contexto nasce um comprometimento quanto a excelência operacional dos sistemas de distribuição de água, buscando uma maior eficiência no estabelecimento de regras operacionais. Para tanto, o objetivo geral desta pesquisa é desenvolver um estudo de calibração de modelos de redes de distribuição de água, pois acredita-se ser a melhor técnica de monitoramento deste problema, por ajustar os parâmetros físicos que foram alterados com o tempo e ditar estratégias para auxiliar a tomada de decisão dos operadores.O presente trabalho visa desenvolver uma técnica de calibração inversa baseada nos AGs como ferramenta de otimização, fazendo uso de objetivos múltiplos: pressão e vazão. Os parâmetros ajustados são: coeficientes de rugosidades e coeficientes de perdas por vazamentos. Para avaliação da metodologia proposta foram empregadas duas redes frequentemente usadas na literatura. A primeira rede empregada por Tucciarelli et al. (1999), é uma rede teórica, e servirá para avaliar o comportamento dos métodos multiobjetivos e seus parâmetros. A segunda rede está localizada na cidade de Campo Grande (MS) foi estudada por Cheung (2004) e Soares et al. (2004). Este exemplo é um sistema real que teve os seus dados medidos em loco e apresenta todas as complicações inerentes aos problemas de calibração real. Os resultados encontrados foram bastante satisfatórios, uma vez que a otimização multiobjetivo demonstrou ser capaz de melhorar a acurácia da calibração do modelo.

Water distribution systems convey drinking water from treatment plant and make available to consumers’ taps. It consists of essential components like pipes, valves, pumps, tanks and reservoirs etc. The main concern in the working of a water distribution system is to assure customer demands under a choice of quantity and quality throughout the complete life span for the probable loading situations. However, in some cases, the existing infrastructure may not be adequate to meet the customer’s requirements. In such cases, system modeling plays an important role in proper management of water supply systems. In present scenario, modeling plays a significant task in appropriate execution of water distribution system. From the angle of taking management decisions valve throttling control and pumps speed control are very important. These operational problems can be addressed by manual control or by automatic control. The problem is the use of manual controls that slow down the effectiveness of the system. It reduces the efficiency of operation of valve or pump. To improve the efficiency of such water distribution systems, an automatic control based technology has been developed that links the operation of the variable speed pump control or valve throttling control. By employing an automatic control, the pump can adjust its speed at all times to meet the actual flow requirements of each load served. In case of real system design Simulink is the most widely used tool. Commercial software package Matlab/Simulink used for creation of WDS model. The goal was to produce a model that could numerically analyze the dynamic performance of a water distribution system. A Comparison of single platform methodology (Simulink based control) and double platform methodology (Matlab and EPANET based control) has been done. Nonlinear Dynamic Inversion (DI) Control system model is developed for WDS model in Matlab/Simulink environment. Controller gain parameters are the very important value in control prospective. If the controller gain parameters are chosen incorrectly, the controlled process input can be unstable, i.e. its output diverges, with or without oscillation Tuning is the adjustment of control parameters (gains) to the optimum values for the desired control response. There are several methods for tuning controller like manual tuning (Trial and error procedure), Ziegler-Nichols method, Output Constraint Tuning (OCT) etc. Establishment of a pump operational policy by which all the reservoirs can be fed simultaneously to meet their requirements without creating undue transients. Tune the gain of DI controllers by different tuning methods and evaluate the best tuning method on the basis of controller performance. Development of meaningful additional objective is search of lower bound pump speed on the basis of control time or settling time. To bring the pump speeds in feasible range, application of constraint in pumps speed is introduced. The magnitude of constraints can be found using Monte Carlo methods. Monte Carlo methods are frequently used in simulating physical and mathematical systems. This method may be the most commonly applied statistical method in engineering and science disciplines. Another benefit is providing increased confidence that a model is robust using Monte Carlo testing. Model development for generalized control system for water distribution network provides the simplification needed for the simulation of large systems. Model development is based on the study of symmetric and non symmetric small, irregular networks, as well as large, regular and open bifurcating water distribution system. The problem considered in this section is that of flow dynamics in simple to complex, regular network which bifurcates in the form of a branching tree. In addition the control application of the flow network is investigated using valves as the manipulated variables to control branch flow rates. Communication between the network hydraulics coming from EPANET and control algorithm develop on Matlab (Programming Language) can be generalized with the help of development of general purpose control algorithm model.

Water distribution networks are a fundamental part of any modern city and their daily operations constitute a significant expenditure in terms of energy and maintenance costs. Careful scheduling of pump operations may lead to significant energy savings and prevent wear and tear. By means of computer simulation, an optimal schedule of pumps can be found by an optimisation algorithm. The subject of this thesis is the study of pump scheduling as an optimisation problem. New representations of pump schedules are investigated for restricting the number of potential schedules. Recombination and mutation operators are proposed, in order to use the new representations in evolutionary algorithms. These new representations are empirically compared to traditional representations using different network instances, one of them being a large and complex network from UK. By means of the new representations, the evolutionary algorithm developed during this thesis finds new best-known solutions for both networks. Pump scheduling as the multi-objective problem of minimising energy and maintenance costs in terms of Pareto optimality is also investigated in this thesis. Two alternative surrogate measures of maintenance cost are considered: the minimisation of the number of pump switches and the maximisation of the shortest idle time. A single run of the multi-objective evolutionary algorithm obtains pump schedules with lower electrical cost and lower number of pump switches than those found in the literature. Alternatively, schedules with very long idle times may be found with slightly higher electrical cost. Finally, ant colony optimisation is also adapted to the pump scheduling problem. Both Ant System and Max-Min Ant System are tested. Max-Min Ant System, in particular, outperforms all other algorithms in the large real-world network instance and obtains competitive results in the smallest test network. Computation time is further reduced by parallel simulation of pump schedules.

Advances in information technology in the past two decades have seen innovations in the field of domestic and industrial computing that led to a paradigm shift in the management and operation of urban water systems by water utility companies. The traditional public management policy that focused on ensuring a minimum quality of service regardless of the costs associated with the processes of catchment, treatment and distribution of water, in many cases even unknown, have evolved towards more efficient cost sensitive models. These new wholly or partly public funded management systems improve not only the quality of service offered to users, but also optimize resources by reducing the cost and causing the minimum environmental impact. The new challenges raised by the European Water Framework1 Directive by imposing cost recovery to improve water efficiency and environmental sustainability have led to a significant change at all levels of water management. Consequently, new priorities have been established in terms of infrastructure management that require the reduction of water losses and the improvement of the water efficiency in urban networks for human consumption. Likewise, in a broader context which includes the water--energy binomial, it is also desirable to improve the energy efficiency and carbon emissions of these systems. Today, network sectoring is the most commonly used strategy to improve management and increase network performance. It basically consists of dividing the network into several smaller hydraulic sectors, where water inlets and outlets are perfectly controlled. This simplifies the task of carrying out periodic water balances in each of the sectors, and allows water loss volume to be assessed for a given period of time. As configuring network sectors is not a trivial task, it is therefore important to have appropriate tools to perform the task efficiently and effectively. Mathematical models can play an important role as decision support tools to help water managers assess the performance of water network distribution systems. This thesis aims to address the current problems of managing urban water networks by combining new information-processing technologies with innovative network modelling techniques. It intends to facilitate the system diagnosis and extend the use of models on the decision-making process to provide better solutions to the management of urban water networks. For this purpose a software extension that works on a geographic information system (GIS) has been developed. It integrates: the hydraulic and water quality simulation program EPANET 2, innovative tools for model analysis and diagnostic, automatic tools for sectoring and computing tools to conduct water balances in the sectors using actual measurements. The work demonstrates the compatibility and complementarity of GIS and hydraulic models as technologies that can be used to support the assessment and diagnosis of water distribution networks. Considering that the majority of information linked to the network system has some geographic reference, it is not surprising that GIS has become a popular tool for dealing with such information. At the same time, the integration of mathematical modelling and simulation tools, offers the GIS a new dimension in the realm of hydraulic study of water networks. Furthermore, if this specific integration is provided with new features aimed not only to facilitate the model building, but also to assist the user in decision-making using powerful algorithms based on the application of the graph theory, the result is a powerful up-to-date analytical tool, which opens up new possibilities in the field of management and efficient operation of urban water supply systems. / Bartolín Ayala, HJ. (2013). Confección de modelos de redes de distribución de agua desde un Sig y desarrollo de herramientas de apoyo a la toma de decisiones [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/33152