Simulação em tempo real de sistemas de distribuição de energia elétrica utilizando-se estruturas com descrição de hardware em software

Pós-graduação em Engenharia Elétrica - FEIS

Estimation of a preference map of new consumers for spatial load forecasting simulation methods using a spatial analysis of points

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Avaliação de plantadora de cana-de-açúcar com sulcador de desarme automático e rotação da esteira distribuidora

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Viabilidade econômica da implantação de compensadores série dinâmicos em redes de distribuição de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Estimação espaço-temporal das perdas não técnicas no sistema de distribuição de energia elétrica

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Distorções harmônicas produzidas por inversores de geração distribuída fotovoltaica em condição de ressonância paralela

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Aplicação das normas para adequação de subestação

The first approach in this work is the concept of the electric power transmission and distribution system, as well as the survey of the current condition of substations chosen to thus identify the importance of having a suitable design with respect to security due to the need to obtain the approval for the operation of the substation according to the standards valid in the country. Present the guidelines and present needs when designing improvements, thus ensuring the company for more safety and reliability. From the company's point of view is an opportunity to reduce the cost of maintenance, and the professional point of view is an opportunity that allows a comprehensive study of legal requirements for the operation of substations

Diagnóstico e proposição de medidas para o controle das perdas de água no sistema de abastecimento de Guaratinguetá

Over the past two years, Brazil has been facing a major water crisis in its history and the state of Sao Paulo is the one that has been going through worst difficulties. In this scenario, all water users should do everything possible so that the consumption of water resources is carried out in a sustainable manner. In this context, the companies responsible for the public water supply must increase the efficiency of water resource management. It is indispensable combating losses in the public supply system. When there is a non-visible leak in a pipe, the wastewater volume can be high, but in this case, the water returns to nature and continues to participate in the hydrological cycle. The economic loss corresponds to the value added to the product water, which includes the intrinsic costs of exploration, processing and distribution. This damage results in a reduced availability of financial resources of sanitation companies to invest in environmentally friendly solutions. This study aimed to diagnose the water distribution system in the city of Guaratinguetá (SP), held by the Companhia de Serviços de Água, Esgoto e Resíduos de Guaratinguetá (SAEG), to propose measures to combat water loss. Among the proposed measures, there is the monitoring of losses, planning for replacement of old pipes and company awareness as a whole in relation to combat water losses

Aplicação das normas para adequação de subestação

The first approach in this work is the concept of the electric power transmission and distribution system, as well as the survey of the current condition of substations chosen to thus identify the importance of having a suitable design with respect to security due to the need to obtain the approval for the operation of the substation according to the standards valid in the country. Present the guidelines and present needs when designing improvements, thus ensuring the company for more safety and reliability. From the company's point of view is an opportunity to reduce the cost of maintenance, and the professional point of view is an opportunity that allows a comprehensive study of legal requirements for the operation of substations

Diagnóstico e proposição de medidas para o controle das perdas de água no sistema de abastecimento de Guaratinguetá

Over the past two years, Brazil has been facing a major water crisis in its history and the state of Sao Paulo is the one that has been going through worst difficulties. In this scenario, all water users should do everything possible so that the consumption of water resources is carried out in a sustainable manner. In this context, the companies responsible for the public water supply must increase the efficiency of water resource management. It is indispensable combating losses in the public supply system. When there is a non-visible leak in a pipe, the wastewater volume can be high, but in this case, the water returns to nature and continues to participate in the hydrological cycle. The economic loss corresponds to the value added to the product water, which includes the intrinsic costs of exploration, processing and distribution. This damage results in a reduced availability of financial resources of sanitation companies to invest in environmentally friendly solutions. This study aimed to diagnose the water distribution system in the city of Guaratinguetá (SP), held by the Companhia de Serviços de Água, Esgoto e Resíduos de Guaratinguetá (SAEG), to propose measures to combat water loss. Among the proposed measures, there is the monitoring of losses, planning for replacement of old pipes and company awareness as a whole in relation to combat water losses

Efficient Forest Data Structure for Evolutionary Algorithms Applied to Network Design

The design of a network is a solution to several engineering and science problems. Several network design problems are known to be NP-hard, and population-based metaheuristics like evolutionary algorithms (EAs) have been largely investigated for such problems. Such optimization methods simultaneously generate a large number of potential solutions to investigate the search space in breadth and, consequently, to avoid local optima. Obtaining a potential solution usually involves the construction and maintenance of several spanning trees, or more generally, spanning forests. To efficiently explore the search space, special data structures have been developed to provide operations that manipulate a set of spanning trees (population). For a tree with n nodes, the most efficient data structures available in the literature require time O(n) to generate a new spanning tree that modifies an existing one and to store the new solution. We propose a new data structure, called node-depth-degree representation (NDDR), and we demonstrate that using this encoding, generating a new spanning forest requires average time O(root n). Experiments with an EA based on NDDR applied to large-scale instances of the degree-constrained minimum spanning tree problem have shown that the implementation adds small constants and lower order terms to the theoretical bound.

Performance tests of two small trigeneration pilot plants

Trigeneration systems have been used with advantage in the last years in distributed electricity generation systems as a function of a growth of natural gas pipeline network distribution system, tax incentives, and energy regulation policies. Typically, a trigeneration system is used to produce electrical power simultaneously with supplying heating and cooling load by recovering the combustion products thermal power content that otherwise would be driven to atmosphere. Concerning that, two small scale trigeneration plants have been tested for overall efficiency evaluation and operational comparison. The first system is based on a 30 kW (ISO) natural gas powered microturbine, and the second one uses a 26 kW natural gas powered internal combustion engine coupled to an electrical generator as a prime mover. The stack gases from both machines were directed to a 17.6 kW ammonia-water absorption refrigeration chiller for producing chilled water first and next to a water heat recovery boiler in order to produce hot water. Experimental results are presented along with relevant system operational parameters for appropriate operation including natural gas consumption, net electrical and thermal power production, i.e., hot and cold water production rates, primary energy saving index, and the energy utilization factor over total and partial electrical load operational conditions. (c) 2011 Elsevier Ltd. All rights reserved.

Nondetection Index of Anti-Islanding Passive Protection of Synchronous Distributed Generators

Synchronous distributed generators are prone to operate islanded after contingencies, which is usually not allowed due to safety and power-quality issues. Thus, there are several anti-islanding techniques; however, most of them present technical limitations so that they are likely to fail in certain situations. Therefore, it is important to quantify and determine whether the scheme under study is adequate or not. In this context, this paper proposes an index to evaluate the effectiveness of anti-islanding frequency-based relays commonly used to protect synchronous distributed generators. The method is based on the calculation of a numerical index that indicates the time period that the system is unprotected against islanding considering the global period of analysis. Although this index can precisely be calculated based on several electromagnetic transient simulations, a practical method is also proposed to calculate it directly from simple analytical formulas or lookup tables. The results have shown that the proposed approach can assist distribution engineers to assess and set anti-islanding protection schemes.

Nitrogen fertilizer (15N) leaching in a central pivot fertigated coffee crop

Nitrogen has a complex dynamics in the soil-plant-atmosphere system. N fertilizers are subject to chemical and microbial transformations in soils that can result in significant losses. Considering the cost of fertilizers, the adoption of good management practices like fertigation could improve the N use efficiency by crops. Water balances (WB) were applied to evaluate fertilizer N leaching using 15N labeled urea in west Bahia, Brazil. Three scenarios (2008/2009) were established: i) rainfall + irrigation the full year, ii) rainfall only; and iii) rainfall + irrigation only in the dry season. The water excess was considered equal to the deep drainage for the very flat area (runoff = 0) with a water table located several meters below soil surface (capillary rise = 0). The control volume for water balance calculations was the 0 - 1 m soil layer, considering that it involves the active root system. The water drained below 1 m was used to estimate fertilizer N leaching losses. WB calculations used the mathematic model of Penman-Monteith for evapotranspiration, considering the crop coefficient equal to unity. The high N application rate associated to the high rainfall plus irrigation was found to be the main cause for leaching, which values were 14.7 and 104.5 kg ha-1 for the rates 400 and 800 kg ha-1 of N, corresponding to 3.7 and 13.1 % of the applied fertilizer, respectively.