Fast and Practical Method for Model Reduction of Large-Scale Water-Distribution Networks

The paper presents a method for the reduction of network models described by a system of non-linear algebraic equations. Such models are, for example, present when modeling water networks, electrical networks and gas networks. The approach calculates a network model, equivalent to the original one, but which contains fewer components. This procedure has an advantage compared to straightforward linearization because the reduced non-linear model preserves the non-linearity of the original model and approximates the original model in a wide range of operating conditions. The method is applicable to hydraulic analysis especially for preparing reduced models for the optimal scheduling studies and has been validated by simplifying many practical water network models for optimization studies.This research was supported by Engineering and Physical Sciences Research Council (EPSRC) grant GR/N26005 and by the Spanish Ministry of Science and Technology, grant BIA2004-06444.Martínez Alzamora, F.; Ulanicki, B.; Salomons, E. (2014). Fast and Practical Method for Model Reduction of Large-Scale Water-Distribution Networks. Journal of Water Resources Planning and Management. 140(4):444-456. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000333444456140

Improving the performance of water distribution systems’ simulation on multicore systems

The final publication is available at Springer via http://dx.doi.org/10.1007/s11227-015-1607-5Hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDS) are used extensively, and their computational performance is key when considering optimization problems. This paper presents an approach to speedup the hydraulic solver using OpenMP with two efficient methods for WDS simulation. The paper identifies the different tasks carried out in the simulation, showing their contribution to the execution time, and selecting the target tasks for parallelization. After describing the algorithms for the selected tasks, parallel OpenMP versions are derived, with emphasis on the task of linear system update. Results are presented for four different large WDS models, showing considerable reduction in computing timeThis work has been partially supported by Ministerio de Economia y Competitividad from Spain, under the project TEC2012-38142-C04-01, and by project PROMETEO FASE II 2014/003 of Generalitat Valenciana.Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2016). Improving the performance of water distribution systems’ simulation on multicore systems. Journal of Supercomputing. 1-13. https://doi.org/10.1007/s11227-015-1607-5S113Abraham E, Stoianov I (2015) Efficient preconditioned iterative methods for hydraulic simulation of large scale water distribution networks. Proc Eng 119:623–632Abraham E, Stoianov I (2015) Sparse null space algorithms for hydraulic analysis of large-scale water supply networks. J Hydraul Eng. doi: 10.1061/(ASCE)HY.1943-7900.0001089Alonso JM, Alvarruiz F, Guerrero D et al (2000) Parallel computing in water network analysis and leakage minimization. J Water Resour Plan Manag 126(4):251–260Alvarruiz F, Martínez-Alzamora F, Vidal AM (2015) Efficient simulation of water distribution systems using openmp. In: 15th International conference computational and mathematical methods in computational mathematics, science and engineering, pp 125–129Alvarruiz F, Martínez-Alzamora F, Vidal AM (2015) Improving the efficiency of the loop method for the simulation of water distribution systems. J Water Resour Plan Manag 141(10):04015019Burger G, Sitzenfrei R, Kleidorfer M, Rauch W (2015) Quest for a new solver for EPANET 2. J Water Resour Plan Manag. doi: 10.1061/(ASCE)WR.1943-5452.0000596Creaco E, Franchini M (2014) Comparison of Newton–Raphson global and loop algorithms for water distribution network resolution. J Hydraul Eng 140(3):313–321Creaco E, Franchini M (2015) The identification of loops in water distribution networks. Proc Eng 119:506–515 Computing and Control for the Water Industry (CCWI2015) Sharing the best practice in water managementCrous PA, van Zyl JE, Roodt Y (2012) The potential of graphical processing units to solve hydraulic network equations. J Hydroinf 14:603–612Elhay S, Simpson A, Deuerlein J, Alexander B, Schilders W (2014) Reformulated co-tree flows method competitive with the global gradient algorithm for solving water distribution system equations. J Water Resour Plan Manag 140(12):04014040Epp R, Fowler AG (1970) Efficient code for steady-state flows in networks. J Hydraul Div 96(1):43–56Guidolin M, Burovskiy P, Kapelan Z, Savić D (2010) Cwsnet: an object-oriented toolkit for water distribution system simulations. In: Proceedings of 12th water distribution system analysis symposium, ASCE, Reston, VAGuidolin M, Kapelan Z, Savic D (2013) Using high performance techniques to accelerate demand-driven hydraulic solvers. J Hydroinf 15(1):38–54Guidolin M, Kapelan Z, Savic D, Giustolisi O (2010) High performance hydraulic simulations with epanet on graphics processing units. In: Proceedings of 9th international conference on hydroinformaticsOstfeld A, Uber J, Salomons E et al (2008) The battle of the water sensor networks (BWSN): a design challenge for engineers and algorithms. J Water Resour Plan Manag 134(6):556–568Rossman AL (2000) Epanet 2 users manual. Water Supply and Water Resources Division, US Environment Protection AgencyTodini E, Pilati S (1988) Computer applications in water supply: vol. 1—systems analysis and simulation. In: Coulbeck B, Orr CH (eds) A gradient algorithm for the analysis of pipe networks. Research Studies Press Ltd, Letchworth, Hertfordshire, UK, pp 1–2

Efficient Modeling of Active Control Valves in Water Distribution Systems Using the Loop Method

[EN] This paper presents a novel approach to model pressure- and flow-regulating devices in the context of the Newton-Raphson loop method for water distribution network simulation. The proposed approach uses a symmetric matrix for the underlying linear systems, which enables simpler implementation and faster solution, while producing iterations very close to the global gradient algorithm of EPANET. The structure of the matrix is kept unchanged regardless of the operational status of the valves. The paper presents results that validate its formulation, accuracy, and speed in various case studies.Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2018). Efficient Modeling of Active Control Valves in Water Distribution Systems Using the Loop Method. Journal of Water Resources Planning and Management. 144(10):1-9. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000982S191441

Improving the efficiency of the loop method for the simulation of water distribution networks

Efficiency of hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDSs) is very important, especially in the context of optimization and risk analysis problems, where the hydraulic simulation has to be repeated many times. Among the methods used for hydraulic solvers, the most prominent nowadays is the global gradient algorithm (GGA), based on a hybrid node-loop formulation. Previously, another method based just on loop flow equations was proposed, which presents the advantage that it leads to a system matrix that is in most cases much smaller than in the GGA method, but has also some disadvantages, mainly a less sparse system matrix and the fact that introducing some types of valves requires the redefinition of the set of network loops initially defined. The contribution of this paper is to present solutions for overcoming the mentioned disadvantages of the method based on loop flow equations. In particular, efficient procedures are shown for selecting the network loops so as to achieve a highly sparse matrix and methods are presented to incorporate check valves and automatic control valves while avoiding the need to redefine the loops initially selected. (C) 2015 American Society of Civil Engineers.This work has been partially supported by "Ministerio de Economia y Competitividad" from Spain, under the project TEC2012-38142-C04-01 and by PROMETEO FASE II 2014/003 project of Generalitat Valenciana.Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2015). Improving the efficiency of the loop method for the simulation of water distribution networks. Journal of Water Resources Planning and Management. 141(10):1-10. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000539S1101411

Digital Twins-A new paradigm for water supply and distribution networks

[EN] A digital twin (DT) is a virtual copy (a digital model) of a real system continuously fed with data to mimic the systems¿ past, present and future behaviour. This makes it possible to detect anomalies, test new ideas and changes in the virtual system and assess how it reacts, minimizing the risks to the real system. In this sense, the DT can be seen as a playground to explore the effects of different scenarios and to practice how to best react and operate the physical system under these circumstances. The concept of DT has been used traditionally in the industry field but it can also be developed and exploited in a city management context, and in particular in Water Supply and Distribution Networks (WSDN), where it can be applied to all aspects of the system.Martínez Alzamora, F.; Conejos Fuertes, MP.; Castro-Gama, M.; Vertommen, I. (2021). Digital Twins - A new paradigm for water supply and distribution networks. Hydrolink Magazine. 2:48-54. http://hdl.handle.net/10251/1901594854

A Decision Support Tool for Water Supply System Decentralization via Distribution Network Sectorization

[EN] Many water supply systems, conceived to operate in centralized manner, face difficulties to adapt to dynamic changes, such as population growth, city extension, and industrial development. Decentralization of these systems may be an effective solution. Known techniques for distribution network sectorization design can help to achieve such a goal, but this has not been recognized in the literature. None of those known techniques considers the conversion of a centralized system to a decentralized one. In this paper, two new distinct yet complementary methodologies for water supply system decentralization by distribution network sectorization are proposed and implemented in a software decision support tool freely available on internet. The first methodology identifies the main flow paths from water sources to some strategic nodes and considers the nodes in these paths as new potential sources for dividing the rest of the network. The second methodology sectorizes the network according to the contribution of sources to the consumption at nodes, based on mass balance equations for the transport of a hypothetical conservative constituent in a steady state. Both methods were applied to two real network models. The results obtained were better, for decentralizing the supply, compared to those obtained by other methodologies proposed in the literature.The main author of this paper wishes to thank the National Studentship Program of Peru for financing his doctoral studies at the Polytechnic University of Valencia, Spain.Vegas Niño, OT.; Martínez Alzamora, F.; Tzatchkov, VG. (2021). A Decision Support Tool for Water Supply System Decentralization via Distribution Network Sectorization. Processes. 9(4):1-15. https://doi.org/10.3390/pr9040642S1159

Real-time energy optimization of irrigation scheduling by parallel multi-objective genetic algorithms

[EN] The present work is motivated by the need to reduce the energy costs arising from the pressure demands of drip and sprinkling irrigation, compounded by the increase in the energy price in recent years. Researchers have demonstrated that proper operation of the irrigation network reduces associated pumping costs. The main challenge was to obtain the optimal operation parameters on near real-time due to the fact that the high complexity of the optimization problem requires a great computational effort. The classic approach to the problem imposes a strict fulfilment of minimum pressures as a restriction. This study, however, presents a new methodology for the reordering of irrigation scheduling, incorporating the constraint of daily volume requests for each hydrant. The methodology is capable of minimizing the cost of energy while maximizing pressures at the critical hydrants. Cost reductions of about 6¿7% were reached for scenarios without pressure deficit for the case study. Greater computational efficiency was achieved by posing the problem from a multi-objective approach, on the one hand, and by establishing the parallel evaluation of the objective function, on the other. The speed-up obtained by combining a reduction in the number of function evaluations thanks to the faster convergence of the multi-objective approach and the reduction of the computational time due to the parallelization of the algorithm achieved results about 10 times faster. This improvement allowed the tool to be implemented for the daily optimization of irrigation requests.This work has been supported by the VALi+D R&D Program of the Generalitat Valenciana (Spain).Alonso-Campos, J.; Jiménez Bello, MA.; Martínez Alzamora, F. (2020). Real-time energy optimization of irrigation scheduling by parallel multi-objective genetic algorithms. Agricultural Water Management. 227:1-8. https://doi.org/10.1016/j.agwat.2019.105857S1822

iDistritos: Sectorización de modelos de redes hidráulicas de Epanet

[ES] La sectorización de una red de suministro de agua es una técnica muy utilizada para mejorar la eficiencia hidráulica del sistema (localización de fugas, gestión de la presión, etc.). Numerosas metodologías se han desarrollado para abordar este problema. Sin embargo, no todas se pueden aplicar a las necesidades particulares de cada sistema de suministro. Por ello se ha desarrollado una herramienta informática (iDistritos), basada en los algoritmos de búsqueda de la teoría de grafos y el simulador hidráulico de Epanet, para proponer e identificar sectores de demanda. La herramienta se ha aplicado en dos redes de agua potable reales en España y México.[EN] Water distribution network sectorization is a widely used technique to improve water system hydraulic efficiency (for leak location, pressure management, etc.). Several methodologies have been developed to address this problem. Not all of them can be applied to solve the particular needs of every supply system, however. Thus, a software tool (iDistricts) was developed, based on graph theory search algorithms and the Epanet hydraulic simulator, to propose and identify demand sectors. The tool has been applied two models of drinking water networks in Spain and Mexico.Vegas, O.; Martínez Alzamora, F.; Tzatchkov, V. (2021). iDistritos: Sectorización de modelos de redes hidráulicas de Epanet. Revista Hidrolatinoamericana de Jóvenes Investigadores y Profesionales. 5:13-15. http://hdl.handle.net/10251/1898981315

Building and exploiting a Digital Twin for the management of drinking water distribution networks

[EN] Digital Twins (DTs) are starting to be exploited to improve the management of water distribution systems (WDSs) and, in the future, they will be crucial for decision making. In this paper, the authors propose several requirements that a DT of a water distribution system should accomplish. Developing a DT is a challenge, and a continuous process of adjustments and learning is required. Due to the advantages of having a DT of the WDS always available, during the last years a strategy to build and maintain a DT of the water distribution network of Valencia (Spain) and its Metropolitan Area (1.6 million inhabitants) was developed. This is one of the first DTs built of a water utility, being currently in operation. The great benefits of their use in the daily operation of the system ensure that they will begin to be usual in the most advanced smart cities.Conejos Fuertes, P.; Martínez Alzamora, F.; Hervás-Carot, M.; Alonso Campos, JC. (2020). Building and exploiting a Digital Twin for the management of drinking water distribution networks. Urban Water Journal. 17(8):704-713. https://doi.org/10.1080/1573062X.2020.1771382S704713178Chacón Ramírez, E., Albarrán, J. C., & Cruz Salazar, L. A. (2019). The Control of Water Distribution Systems as a Holonic System. Studies in Computational Intelligence, 352-365. doi:10.1007/978-3-030-27477-1_27Grieves, M., et al. 2015. Virtually Intelligent Product Systems: Digital and Physical Twins. In Complex Systems Engineering: Theory and Practice, edited by S. Flumerfelt, et al., 175–200. American Institute of Aeronautics and Astronautics.Hatchett, S., J. Uber, D. Boccelli, T. Haxton, R. Janke, A. Kramer, A. Matracia, and S. Panguluri. 2011. “Real-Time Distribution System Modeling: Development, Application, and Insights.” Urban Water Management: Challenges and Oppurtunities - 11thInternational Conference on Computing and Control for the Water Industry, CCWI 2011 July.Kartakis, S., Abraham, E., & McCann, J. A. (2015). WaterBox. Proceedings of the 1st ACM International Workshop on Cyber-Physical Systems for Smart Water Networks. doi:10.1145/2738935.2738939Lin, J., Sedigh, S., & Miller, A. (2009). Towards Integrated Simulation of Cyber-Physical Systems: A Case Study on Intelligent Water Distribution. 2009 Eighth IEEE International Conference on Dependable, Autonomic and Secure Computing. doi:10.1109/dasc.2009.140Qi, Q., & Tao, F. (2018). Digital Twin and Big Data Towards Smart Manufacturing and Industry 4.0: 360 Degree Comparison. IEEE Access, 6, 3585-3593. doi:10.1109/access.2018.2793265Alac, M. (2008). Working with Brain Scans. Social Studies of Science, 38(4), 483-508. doi:10.1177/0306312708089715Shi, Y., Xu, J., & Du, W. (2019). Discussion on the New Operation Management Mode of Hydraulic Engineering Based on the Digital Twin Technique. Journal of Physics: Conference Series, 1168, 022044. doi:10.1088/1742-6596/1168/2/022044Tao, F., Zhang, H., Liu, A., & Nee, A. Y. C. (2019). Digital Twin in Industry: State-of-the-Art. IEEE Transactions on Industrial Informatics, 15(4), 2405-2415. doi:10.1109/tii.2018.2873186Tao, F., Cheng, J., Qi, Q., Zhang, M., Zhang, H., & Sui, F. (2017). Digital twin-driven product design, manufacturing and service with big data. The International Journal of Advanced Manufacturing Technology, 94(9-12), 3563-3576. doi:10.1007/s00170-017-0233-1Tao, F., & Qi, Q. (2019). Make more digital twins. Nature, 573(7775), 490-491. doi:10.1038/d41586-019-02849-1Uber, J., S. Hatchett, S. Hooper, D. Boccelli, H. Woo, and R. Janke. 2014. Water Utility Case Study of Real-Time Network Hydaulic and Water Qualilty Modeling Using EPANET-RTX Libraries. EPA 6007R-14/350 Report. Cincinnati, Ohio: Environmental Protection Agency.Wang, Z., Song, H., Watkins, D. W., Ong, K. G., Xue, P., Yang, Q., & Shi, X. (2015). Cyber-physical systems for water sustainability: challenges and opportunities. IEEE Communications Magazine, 53(5), 216-222. doi:10.1109/mcom.2015.710566

Efficient Simulation of Water Distribution Systems using OpenMP

[EN] Hydraulic solvers for the simulation of flows and pressures in water distribution systems (WDS) are used extensively, and their computational performance is key when considering optimization problems. This paper presents an approach to speedup the hydrualic solver using OpenMP. The procedure is based on a parallel algorithm for the generation of the linear system of equations. Preliminary results show the validity of the approach.The authors would like to thank the Spanish “Ministerio de Economía y Competitividad” fort he project “Migrable Elastic Virtual Clusters on Hybrid Cloud Infrastructures” (TIN2013-44390-R).Alvarruiz Bermejo, F.; Martínez Alzamora, F.; Vidal Maciá, AM. (2015). Efficient Simulation of Water Distribution Systems using OpenMP. CMMSE. http://hdl.handle.net/10251/75303