Papers by Edevar Luvizotto
Anais do Congresso de Iniciação Científica da Unicamp, Oct 21, 2017
Integrated management of water supply systems with efficient use of resources requires optimizati... more Integrated management of water supply systems with efficient use of resources requires optimization of operational performances. Clustering the water supply networks into small units, so-called district metered areas (DMAs), is a strategy that allows the development of specific operational rules, responsible for improving the network performance. In this context, clustering methods congregate neighboring nodes in groups according to similar features, such as elevation or distance to the water source. Taking into account hydraulic, operational and mathematical criteria to determine the configuration of DMAs, this work presents k-means model and a hybrid model, that combines a self-organizing map (SOM) with k-means algorithm, as clustering methods, comparing four clustering mathematical criteria, namely Silhouette, GAP, Calinski-Harabasz and Davies-Bouldin; and analyzing the influence of varying three clustering topological criteria, the water demand, node elevation and pipe length, in order to determine the optimal number of clusters. Furthermore, to identify the best DMA configuration, the particle swarm optimization (PSO) method is applied to determine the number and location of DMA entrances.
Social Science Research Network, Nov 30, 2017
Spanish Abstract: Los sistemas de abastecimiento de agua estan frecuentemente expuestos a problem... more Spanish Abstract: Los sistemas de abastecimiento de agua estan frecuentemente expuestos a problemas operacionales que llevan a comportamientos inesperados (eventos anomalos). La deteccion de eventos anomalos puede ser de gran importancia para las empresas de abastecimiento porque permiten la rapida restitucion del servicio en condiciones adecuadas, reduciendo las perdidas fisicas por la ocurrencia de fugas y aumentando la satisfaccion de los usuarios finales. Teniendo como base un estudio de caso para un distrito de medicion en la ciudad de Santa Barbara do Oeste (SP-Brasil), este trabajo presenta una metodologia para la deteccion de eventos anomalos en la operacion de redes de abastecimiento de agua utilizando el analisis de datos de demanda de la entrada del sector, para lo cual se ha implementado un modelo de prevision de demanda en tiempo real basado en redes neuronales recurrentes no-lineales (NARX). Posteriormente se aplican dos metodologias para analizar el error: Puntos de Cambios Abruptos y mapas de Sumas Acumulativas. Con el modelo de prevision es posible estimar la curva de prevision de demanda y junto con el analisis del error de este modelo, es posible identificar los eventos anomalos de baja magnitud que no son evidentes de forma grafica en una primera aproximacion. La comparacion entre la curva de prevision de demanda y los datos reales de demanda permite definir intervalos de variacion del error con los cuales es posible identificar las anomalias con una mayor precision. English Abstract: The water supply systems are currently exposed to operational problems, which cause unexpected behaviors (anomalous events). The anomalous events detection may be relevant for the water supply companies because they allow rapid restitution of the service in suitable conditions, reducing the leaks and increasing the users’ satisfaction. Based on the case of study of the Santa Barbara do Oeste city (SP-Brazil), this work presents a methodology for anomalous events detection in the operation of water supply networks using demand data analysis in the sector entrance by implementing a forecasting demand model based in neural networks nonlinear autoregressive (NARX). Afterwards, two methodologies are applied to analyze the error: Abrupt Change Points and Cumulative Sums Maps (CUSUM). With the forecasting model is possible to identify the anomalous events of low scale, which are not graphically evident at first view. The comparison between the forecasting demand curve and the real demand data allows to define intervals of error variation making possible to identify the anomalous events with greater accuracy.
Universal access to drinkable water is a constitutional right guaranteed in Brazil. However, not ... more Universal access to drinkable water is a constitutional right guaranteed in Brazil. However, not all cities in this country are able to supply the population with the expected quality. Important actions should be taken to improve the supply of drinkable water. To define a strategic plan for this purpose, classification tools can facilitate the design of plans, by grouping cities with similar quality conditions. During the last decades, neural network approaches have been used in environmental models, allowing more accurate representation of some complex systems. This work proposes the use of self-organizing maps (SOM's) coupled with the k-means algorithm to determine city groups (clusters) based on water quality features available at the National System of Sanitation Information (SNIS). Using the Calinski-Harabaz (CH) index for clustering performance analysis, an optimal number of clusters is defined. The objective of this clustering is to clarify the real conditions, to understand the main service deficits from the water quality perspective, and to plan suitable strategies to reduce these deficits.
Water distribution network (WDN) operation may be improved by district metered area (DMA) design ... more Water distribution network (WDN) operation may be improved by district metered area (DMA) design [1]. A first step to create DMAs uses graph theory and non-supervised learning, where physical features of the WDN, such as node coordinates, elevation and demand, are used for clustering purposes [2]. A second step is related to the necessary isolation of the clustered elements. For isolation purposes, it is important to determine the DMA entrances and, consequently, the needed cut-off valves. Closure of pipes and definition of DMA entrances can be set as an optimization problem with the costs associated to the valves, which are linked to pipe diameters, as a primary objective. However, placement and operation of pressure reducing valves (PRVs) change the hydraulic conditions, and the optimization process should respect operation limits, such as minimum and maximum pressure and minimum and maximum tank levels. Constrained problems are frequently handled by using penalty functions. However, as discussed in [3], penalty approaches modify the search space, impairing the search process by the creation of new local minima. To solve this problem, a bio-inspired algorithm widely applied in water distribution problems [4], adapted for a multi-objective approach, is applied. In this context, constraints become objectives to be reached, which turns the problem unconstrained. Moreover, as observed in [5], such crucial water distribution parameters as resilience, pressure uniformity and water quality strongly depend on DMA configurations. These parameters are known to depend on pressures and water tank levels and, together with cost, will be the other objectives of our optimization. A multi-objective approach gives a set of solutions, the so-called Pareto front. To select, within that front, which non-dominated solution will be implemented may be hard task. To help this process, this work presents: a) multi-level optimization process for entrance location and set point definition of PRVs, and b) a post-processing based on a multi-criteria method, which ranks the non-dominated solutions based on the relative importance of the said four main objectives: implementation cost, resilience, pressure uniformity and water quality. Among the wide range of MCDM (multi-criteria decision-making) methods used in the literature, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) effectively works across various application areas [6]. Such a technique was developed by Hwang and Yoon [7] as a simple way to solve decision-making problems by means of the ranking of various decision alternatives [8,9]. In this context, the objective of the TOPSIS application to the multi-objective problem consists in selecting the solution representing the best trade-off (among the set of optimal solutions belonging to the Pareto front) under the perspective of the considered evaluation criteria
Anais do Congresso de Iniciação Científica da Unicamp, Nov 20, 2015
The water distribution networks play a key role in the urban water supply systems. With the curre... more The water distribution networks play a key role in the urban water supply systems. With the current urban growth, when designing or expanding any distribution network it is extremely important that water demand is provided according to the standards and with the lowest cost possible of implementation. In order to find the most economical diameters to satisfy supply networks projects, this research developed an optimization algorithm, based on the meta-heuristics optimization technique called Simulated Annealing, combined with a hydraulic simulator, called Epanet toolkit, which was developed by USA EPA. This hydraulic simulator ensured that the solution found by the optimizer was consistent with operational constraints, such as the service pressure. Several tests with the Hanoi network were performed to evaluate the algorithm that resulted in a solution next to those found in the literature.
Proceedings of the 34th World Congress of the International Association for Hydro- Environment Research and Engineering: 33rd Hydrology and Water Resources Symposium and 10th Conference on Hydraulics in Water Engineering, 2011
This paper presents a case study of a water main system located at Jundia , SP, Brazil that suppl... more This paper presents a case study of a water main system located at Jundia , SP, Brazil that supplies a group of four tanks. The water main supplies five neighborhoods. The system has nine pipes and ten nodes. The four tanks work simultaneously and all of them have altitude valves installed on their inlets. The tanks work under different water demands and pressures and are located on different places (nodes). Software was developed to study the undesirable hydraulic transients produced on the water main due to wrong altitude valve settings on the four tank inlets and to yield a solution to control the hydraulic transients.
Revista Brasileira de Recursos Hídricos, May 28, 2018
This is an Open Access article distributed under the terms of the Creative Commons Attribution Li... more This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Gauging flow velocity in 2 positions for discharge calculation in pipes Medindo a velocidade de escoamento em 2 posições para o cálculo da vazão em tubos
Journal of Hydraulic Engineering, Aug 1, 2017
AbstractModeling of hydraulic machines is fundamental in steady and unsteady analysis. The simula... more AbstractModeling of hydraulic machines is fundamental in steady and unsteady analysis. The simulations carried out in different scenarios will define the need for protection devices or other mechan...
IOP conference series, Aug 1, 2010
There are several governor architectures, but in general, all of them are designed to maintain th... more There are several governor architectures, but in general, all of them are designed to maintain the controlled variable fluctuations within acceptable range. The Proportional, Integral and Derivative (PID) governor is one of the types used to regulate a hydraulic turbine, in which the deviation of the variable controlled is corrected through earnings proportional, integral and derivative. For a definition of the governor parameters and its stability analysis there are several methods that in general can be classified into a time domain and frequency domain. The frequency domain method, based on the control theory, have ease application, expeditious manner of obtaining the parameters, but the physical phenomena involved are linearized. However the time domain methods are more difficult to be applied, but have the advantage of being able to take into account the non-linearities presents in physical phenomena. Despite the time-domain method offers advantages, it does not provides a structured way to optimize the parameters of the governor, since the parameters are obtained through simulations with adopted values. This paper presents a methodology to obtain the turbine governor appropriate parameters through a hybrid model (simulation and optimization model), based on method of characteristic to the hydraulic simulation (time domain) and Genetic Algorithm (GA) to obtain appropriate values. Examples are presented showing the application of the proposed methodology.
In Pumped Storage Schemes (PSS) it is necessary to know the hydrodynamic personality of the whole... more In Pumped Storage Schemes (PSS) it is necessary to know the hydrodynamic personality of the whole installation, in extensive and transient period of operation, in order to prevent inadequate pressure surges and to provide the operational optimization for energy production.
Managing water distribution systems includes detection of leaks to improve the effectiveness of t... more Managing water distribution systems includes detection of leaks to improve the effectiveness of the service. The section of a hydraulic network where a leak occurs can be detected if the SCADA SYSTEM is coupled to a software based on the Method of Characteristics (MOC), which is, presently, the best one to simulate steady and unsteady flows, as shown by illustrative examples in this paper. The paper shows the basic equations and describes the basis of the computer program and corresponding network topology description that provide the engineer with the easiest way to simulate network operation. The use of MOC, for both steady and unsteady flow monitoring, facilitates the network calibration in order to reduce the sensitivity of the data errors due to inaccuracy in the value of friction factors.
Revista Brasileira de Recursos Hídricos, 2006
Este trabalho apresenta um modelo matricial inelástico que calcula redes hidráulicas, baseado no ... more Este trabalho apresenta um modelo matricial inelástico que calcula redes hidráulicas, baseado no método criado por Nahavandi e Catanzaro (1973). Trata-se de um método que permite o cálculo de vazões e da distribuição da pressão em uma rede para o regime permanente, para o regime extensivo e para o regime transitório lento. Este método leva vantagem sobre o método de Cross pelo fato deste último não permitir o cálculo das situações transitórias que ocorrem, por exemplo, durante a abertura e fechamento de uma válvula, partida e parada de um "booster", rompimento de uma tubulação, etc. Foi ampliada a aplicabilidade do método criado por Nahavandi e Catanzaro (1973), pois foram desenvolvidas a programação e a entrada de dados para contemplar a existência de válvulas, reservatórios ou "boosters" na rede. Além disto, toda a formulação matemática e a programação para o cálculo do regime transitório e do regime extensivo também tiveram que ser desenvolvidas. O modelo matricial está funcionando a contento, pois os valores obtidos pelo modelo para as redes utilizadas como exemplo estão próximos dos valores originais obtidos da literatura pesquisada.
Revista Brasileira de Recursos Hídricos, 2006
O problema de cavitação nas estruturas hidráulicas é particularmente importante e em especial, as... more O problema de cavitação nas estruturas hidráulicas é particularmente importante e em especial, as áreas superficiais devem ser resistentes. Em muitos casos, o dano provocado é tão grande que reduz a vida útil da obra e também obriga a longos períodos de interrupção de funcionamento. A erosão provocada por este fenômeno vem acompanhada de outros efeitos indesejáveis que são as vibrações estruturais e o ruído acústico. O objetivo deste trabalho foi desenvolver um equipamento que permita avaliar o desgaste ocasionado pela cavitação em amostras de concreto empregados em estruturas hidráulicas. Um banco de ensaio foi montado utilizando bomba de deslocamento direto e bomba centrífuga. O emprego da bomba de deslocamento direto permitiu o desenvolvimento da cavitação. O equipamento mostrou-se adequado para a realização de ensaios de resistências de concretos, obtendo-se dano nas amostras com tempos de ensaio muito menores que os necessários com outros dispositivos permitindo, portanto, economia de energia e mão de obra. O uso da bomba centrífuga não foi adequado. Conclui-se que para obtenção de desgaste nas amostras de concreto é necessária uma combinação de tempo de ensaio, características da amostra (resistência e componentes) e valores apropriados do índice de cavitação. Os testes com amostras de concretos especiais são necessários para definir a melhor performance e poder empregar com eficiência tanto na construção como no reparo das estruturas sujeitas a este tipo de situação.
IOP Conference Series: Earth and Environmental Science, 2014
The energy generated by wind or solar photovoltaic (PV system) can be used by PSP to accumulate w... more The energy generated by wind or solar photovoltaic (PV system) can be used by PSP to accumulate water in the upper reservoir, in the form of potential energy to be used later, during periods of high energy demand. This procedure offers the advantage of enabling the use of intermittent renewable energy source in times of growing needs of the electric power supply. The location of the PSP, the environmental aspects involved, their possible use for various purposes (stability of the power system at peak times, associate the turbine water for public supply purposes, among others) and the discussion of regulatory issues needs to be debated in the current context, where environmental issues require reliable sources of power generation and demand shows strong growth rates. A dynamic model is used to analyze the behavior of a PSP proposal for a site in Brazil, analyzing a complete cycle of its operation as a pump or turbine. The existing difficulties to use this proposal based on existing regulatory policies are also discussed, and a list of recommended adjustments is provided to allow the penetrations of PSP projects in the Brazilian institutional framework, coupled with other intermittent energy sources.
Water
Valves are widely used in several areas, and their application in building installations is commo... more Valves are widely used in several areas, and their application in building installations is common, e.g., as shower control valves. Rapid technological advances have resulted in improvements to valve performance, reducing water and energy consumption. Removing parts external to the masonry improves space use and ergonomics in valve operation. Front access to the internal parts of a valve facilitates maintenance. The objective of this study is to present a new model of hydraulic valve for building installations, designed to decrease head loss, increase controllability, and eliminate parts outside the masonry. Three geometries were initially designed using SolidWorks, and a CFD model was used to specify the pressures at the inlet and outlet of the analyzed sections. As a result, the third valve geometry presented a pressure drop coefficient when 100% open that was roughly one third of that typically seen in globe valves. The pumps and the reduction in head loss implied that lower powe...
Water
Leakages in distribution networks reach more than 30% of the water supplied, entailing important ... more Leakages in distribution networks reach more than 30% of the water supplied, entailing important risks for the water infrastructure with water contamination issues. Therefore, it is necessary to develop new methods to mitigate the amount of water wastes. This study proposes to seek new sources of information that can help for a more sustainable water use. Hence, an analysis of the network is presented, showing the hydraulic behavior during leaks occurrence, placing emphasis on how these events affect and modify water quality parameters, such as water age and chlorine concentration. The study enhances that water quality data can be an effective source of information in the case of leaks, being a possible source of information for future detection systems. In addition, this study proposes to use graph theory on the water network. The results highlight how an analysis of the shortest path between the leak location and the reservoir could provide meaningful information for future detect...
Journal of Water Resources Planning and Management
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Papers by Edevar Luvizotto