Heber Pimentel Gomes

Generalized Minimum Variance Control for Water Distribution System

This paper presents the project of an adaptive control system to modeling and controlling, in real time, a water distribution system. The controllers act in determining the turning speed of the motor/pump set and in the opening angle of control valves. An experimental workbench was set aiming at modeling and identifying parametrically a hydraulic network. The control system is a Generalized Minimum Variance self-tuning (GMV), whose parameters where real-time estimated by the recursive least squares (MQR) method according to the imposed inputs to the converter and the valves. The GMV aims at the pressure control in measuring points, which provided the reduction of energy and water in the workbench. Experimental results show the performance of adaptive control system and its ability to control the water distribution process.

Calibração multivariada de redes de abastecimento de água via algoritmo genético multiobjetivo

Este trabalho teve por objetivo propor um modelo computacional com vistas a calibracao multivariada de modelos hidraulicos de sistemas de distribuicao de agua que possibilita a identificacao de possiveis irregularidades, como: vazamentos, obstrucoes nas tubulacoes, valvulas inoperantes ou estranguladas e incompatibilidades na modelagem referente aos dados reais. Utiliza um algoritmo genetico multiobjetivo no processo de calibracao para ajustar as diferencas das variaveis de estado da rede, a fim de produzir informacoes compativeis com suas respectivas redes reais. O modelo proposto permite utilizar ate sete variaveis: a rugosidade, a demanda, a perda de carga singular, a cota topografica, os vazamentos, os diâmetros e as valvulas, simultaneamente, ou qualquer combinacao delas. A aplicacao experimental foi realizada no Laboratorio de Eficiencia Energetica e Hidraulica em Saneamento da Universidade Federal da Paraiba (LENHS/UFPB) com os dados do seu Sistema Piloto de Distribuicao de Agua (SPDA). Os resultados mostraram uma boa convergencia com relacao ao tempo de processamento e a aproximacao dos dados medidos e calculados, assim como possibilitaram a identificacao de problemas mediante analise dos parâmetros resultantes da calibracao, o que proporciona subsidios para uma reabilitacao mais precisa.

Sistema de controle adaptativo aplicado a um sistema de distribuição de água com ênfase na eficiência energética

Esta pesquisa objetivou projetar um sistema de controle adaptativo para o modelamento e controle, em tempo real, de um sistema de distribuicao de agua. Os controladores atuaram no controle da pressao por meio da variacao da velocidade de rotacao do sistema de bombeamento e do ângulo de abertura de valvulas de controle. O sistema de controle e do tipo Variância Minima Generalizado (GMV) autoajustavel, cujos parâmetros foram estimados em tempo real pelo metodo dos minimos quadrados recursivo (MQR). Os ensaios realizados na bancada experimental apresentaram resultados satisfatorios, com um erro maximo no controle de pressao de 2,12% (0,42 mca) e uma reducao de 19,2% no consumo de energia eletrica para o sistema atuando na condicao mais desfavoravel.

Reabilitação de redes coletivas de sistemas pressurizados de irrigação

This paper presents a method of economic optimization aiming the rehabilitation of pressurized branched networks of water distribution for irrigation projects, which have flow and pressure deficiency at the consumption points. The method can be applied to looped networks of urban water supply, on condition that they are changed into branched ones, through the fictitious sectioning method. The methodology used is based on the Granados method of economic optimization of pressurized networks, which is an iterative process that selects step by step the possibilities of changes of the network pipe diameters, so as to optimize the investment cost of the rehabilitation system. The method was tested for a distribution network that supplies a fictitious irrigation project, in which there is pressure deficiency in almost all the consumption points. The network rehabilitation cost was 41% of the original cost.

ECONOMIA DE ENERGIA EM SISTEMAS DE BOMBEAMENTO: APLICAÇÃO DE UM SISTEMA FUZZY

This paper deals with the impact of variable speed drives on the power requirements and a system control performance of pumps. The investigation indicates that the adoption of Variable Speed Drives (VSD) reduces pump energy consumption in certain cases, reduces the pressure in the hydraulic networks and improves pump efficiency during most of the partial load conditions. The use of fuzzy system to provide new control functions that are outside the domain of traditional control is sought in this paper, where fuzzy control is likely to provide the greatest payoff. The development and application of a fuzzy control system for a pumping system, operating with variable rotational speed are presented to demonstrate the energy savings provided by the adoption of the PWM frequency inverter in an experimental system. The control system is responsible for maintaining the manometric height of the pump at an optimal value, eliminating any excess pressure at the critical point of the water distribution network. The results of the experiments show that the fuzzy systems are efficient and the control of the rotational speed resulted in a reduction of 35% in the consumption of electricity. Keywords: Fuzzy system, Water distribution system, Energy efficiency, Pressure control, Variable frequency drive. RESUMO Este artigo apresenta a influencia do uso de inversores de frequencia no consumo energetico de sistemas de bombeamentos e o desempenho de um sistema de controle para atuar nesses equipamentos. A pesquisa indica que a adocao de inversores reduz o consumo de energia em determinadas aplicacoes, reduz a pressao nas redes hidraulicas e melhora a eficiencia da bomba. O desenvolvimento e aplicacao de um sistema de controle Fuzzy para conjuntos motor-bomba operando com velocidade de rotacao variavel sao apresentados para demonstrar a economia de energia resultado da adocao do inversor de frequencia PWM em um sistema experimental. O uso deste sistema para condicoes de operacao que estao fora do dominio do controle tradicional e procurado neste trabalho, em que o controle Fuzzy e susceptivel de proporcionar maior retorno. O controlador e responsavel pela manutencao da altura manometrica da bomba em um valor otimo, eliminando qualquer excesso de pressao no ponto critico da rede de distribuicao de agua. Os resultados das experiencias mostraram que o sistema Fuzzy foi eficiente e o controle de velocidade de rotacao resultou numa reducao de 35% no consumo de eletricidade. Palavras-chaves: Sistema Fuzzy, Sistema de distribuicao de agua, Eficiencia energetica, Controle de pressao, Inversor de frequencia.

Aplicação de técnicas Fuzzy no controle de pressão em sistemas de abastecimento de água

The paper presents the development of a Fuzzy system for the pressure control of distribution of water through the use of frequency converters coupled to the motor-pump assemblies. The entire study was conducted in an instrumentalized bench trial simulating a real supply system. The use of pump-motor sets in parallel with the system generated a great number of combination possibilities of variations in speed of the motor-pump assemblies, with different speeds of rotation. The Fuzzy controller identifies the best option for the energy consumption of the system and makes the decision alluding to the state of the engines (on, off or partial rotation). This entire process is performed under the condition of meeting the demand flow system, and maintain constant pressure with the lowest possible energy consumption.

Dimensionamento de sistema de microirrigação através de programação não linear considerando-se diferentes demandas hídricas

In this work the optimum microsprinkler system design is analyzed through optimization model using non linear programming, with the objective of minimizing operational and investment costs, for three sceneries of the water demand in two localities of the Northeast region of Brazil: Iguatu, Ceara State, with annual and monthly water balances, and Joao Pessoa, Paraiba State, with monthly water balance. The model has as decision variables: the lengths of the pipe sections with their respective diameters, the daily irrigation total time, the emission uniformity, the irrigation frequency and the emitter mean operation pressure. The results evidenced that in semi-arid climate areas, as Iguatu, there are not important differences in the design system with the demands obtained through the annual or monthly water balances. The investment cost was not affected by the demands, but just the operational and total system costs. Regions with smaller daily and annual water requirement, as Joao Pessoa, allow larger number of operational units of the system and, therefore, larger reduction of the investment cost. However, for same number of the subunit and operational units the water demands differences do not affect the design. The maximum daily water demand of the crop has larger effect on the hydraulic system than the annual water demand. The system with optimum design depends on the combined analysis of the subunit number and of operational units of the system and the energy cost should not be ignored.