Conversor CA-CA de elevado fator de potência para aplicações com geradores de Ímã permanente

This paper proposes and describes a high power factor AC-AC converter for naval applications using Permanent Magnet Generator (PMG). The three-phase output voltages of the PMG vary from 260 Vrms (220 Hz) to 380 Vrms (360 Hz), depending on load conditions. The proposed converter consists of a Y-/ΔY power transformer, which provides electrical isolation between the PMG and remaining stages, and a twelve-pulse uncontrolled rectifier stage directly connected to a single-phase inverter stage, without the use of an intermediary DC-DC topology. This proposal results in more simplicity for the overall circuitry, assuring robustness, reliability and reduced costs. Furthermore, the multipulse rectifier stage is capable to provide high power factor and low total harmonic distortion for the input currents of the converter. The single-phase inverter stage was designed to operate with wide range of DC bus voltage, maintaining 120 Vrms, 60 Hz output. The control philosophy, implemented in a digital signal processor (DSP) which also contains protection routines, alows series connections between two identical converters, achieving 240 Vrms, 60 Hz total output voltage. Measured total harmonic distortion for the AC output voltage is lower than 2% and the input power factor is 0.93 at 3.6kW nominal load. © 2010 IEEE.

Electrical consumers data clustering through optimum-path forest

Non-technical losses identification has been paramount in the last decade. Since we have datasets with hundreds of legal and illegal profiles, one may have a method to group data into subprofiles in order to minimize the search for consumers that cause great frauds. In this context, a electric power company may be interested in to go deeper a specific profile of illegal consumer. In this paper, we introduce the Optimum-Path Forest (OPF) clustering technique to this task, and we evaluate the behavior of a dataset provided by a brazilian electric power company with different values of an OPF parameter. © 2011 IEEE.

Arc-flash energy: The impact of fuse link manufacturers

The traditional operational and hazard control paradigm of an electrical installation has several issues pertaining to the diversity of equipment. A large maintenance inventory is a reason for concern for any manager, but the arc-flash hazard is a particularly new phenomenon, and the effects of equipment diversity on this phenomenon are even newer. The class of arc hazard can be simply increased by changing the fuse link or circuit breaker manufacturer. Management pressure to operate as well as nonstandard practices and installations are also partly responsible. The aim of this article is to take a typical situation in an industrial plant and to statistically simulate, by means of a dedicated software program, the fuse arc-flash interruption performance of various manufacturers. The purpose of this article is to obtain a more objective indication of the influence of different fuse link manufacturers on arc-flash incident energy. © 1975-2012 IEEE.

Electrical Power Distribution System modeling with VHDL-AMS for the construction of a Real-Time Digital Simulator using FPGAS devices

This paper presents a distribution feeder simulation using VHDL-AMS, considering the standard IEEE 13 node test feeder admitted as an example. In an electronic spreadsheet all calculations are performed in order to develop the modeling in VHDL-AMS. The simulation results are compared in relation to the results from the well knowing MatLab/Simulink environment, in order to verify the feasibility of the VHDL-AMS modeling for a standard electrical distribution feeder, using the software SystemVision™. This paper aims to present the first major developments for a future Real-Time Digital Simulator applied to Electrical Power Distribution Systems. © 2012 IEEE.

Contribuições para avaliação dos impactos econômicos causados por mergulho de tensão em sistema elétrico industrial

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo comparativo de medição de força de corte no processo de retificação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise técnico-econômica da utilização de um gerador à gás natural em um sistema de cogeração: estudo de caso

Pós-graduação em Engenharia Mecânica - FEG

A produção enxuta em um sistema de fabricação contínuo: aplicação da simulação discreta estocástica na indústria de condutores elétricos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Portable meters for nutritional assessment in plants of gerbera fertigated with electrical conductivity levels

Rapid tests to assess the nutritional status of plants gerbera can make easier the decision of any adjustments in the fertilization of the substrate. The study was conducted to evaluate nutritionally fertigated gerbera plants with increasing levels of electrical conductivity (EC), using portable meters nitrate and potassium, and chlorophyll. For this, two experiments were conducted. A randomized block design with five levels of EC (0.5, 2.0, 3.5, 5.0 and 6.5 dS m-1) and four replications was used. Cherry cultivar was used in the first experiment. In the second experiment, two cultivars (Cherry and Salmon Rose) were used. In the first experiment, the sap of the leaves was subjected to rapid testing of N-NO3- (equipment Cardy Horiba C -141). N-NO3- and K+ (C-131) were determined in the substrate solution. The intensity of the green leaf, in the second experiment was evaluated with portable Chlorophyll Meter. The N content in the indicator leaf in the first and N and K contents in the plant in the second experiment were determined. Rapid tests are presented as good indicators of the level of N-NO3- and K+ in plant tissue, with the advantages of convenience and speed of determination, facilitating monitoring of fertilization of the substrate by producers and technicians.

Aumento da oferta de eletricidade no setor sucroalcooleiro: incorporação de ciclo combinado associado à gaseificador de leito fluidizado

Pós-graduação em Engenharia Mecânica - FEG

Thermodynamic and economic analysis of hydrogen production integration in the Brazilian sugar and alcohol industry

One of the biggest challenges today is to develop clean fuels, which do not emit pollutant and with viable implementation. One of the options currently under study is the hydrogen production process. In this context, this work aims to study the technical and economical aspects of the incorporation process of hydrogen producing by ethanol steam reforming in the sugar cane industry and MCFC (molten carbonate fuel cell) application on it to generate electric power. Therefore, it has been proposed a modification in the traditional process of sugar cane industry, in order to incorporate hydrogen production, besides the traditional products (sugar, ethylic, hydrated and anhydric alcohol). For this purpose, a detailed theoretical study of the ethanol production process, describing the considerations to incorporate the hydrogen production will be performed. After that, there will be a thermodynamic study for analysing the innovation of this production chain, as well as a study of economic engineering to allocate the costs of products of the new process, optimising it and considering the thermoeconomics as being as an analysis tool. This proposal aims to improve Brazil's position in the ranking of international biofuels, corroborating the nation to be a power in the hydrogen era. (C) 2013 Elsevier Ltd. All rights reserved.

Análise do consumo de energia elétrica e da eficiência energética em uma indústria de processamento de madeira

In the industries of wood processing (sawmills), where timber is sawn in equipment such as band saws, circular saws, trowel, thicknessers, among others, that mechanically transform this resource and use of electric motors, which are not unusually poorly scaled working or overloaded, often a factor that is not found in these industries and has fundamental importance in the production process is energy efficiency that is achieved by both technological innovation and through all the practices and policies that aim to lower energy consumption, lowering energy costs and increasing the amount of energy offered no change in generation. For both during the design of an electrical installation, both overall and in various sectors of the installation, investigations are necessary, considerations and uses of variables and factors that put into practice the theme of energy efficiency. Therefore, in this paper, these factors were calculated and analyzed for a wood processing industry (sawmill) in the municipality of Taquarivaí - SP, namely: active power, power factor, demand factor and load factor. Where they were small in relation to the literature, these events that occur when devices are connected at the same time and due to the conditions of processing the wood, where the engines have large variations in electricity consumption during the unfolding of the same, due to efforts with the load and idle moments between each machining operation in the equipment

Study of the removal of chemical oxygen demand of the cheese whey and wastewater from dairy industry using Spirulina platensis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Interdisciplinary project applied to engineering education: construction of a miniature ceramic industry

The greatest challenge of undergraduate engineering courses is to encourage creativity, cooperation with other students, teamwork, and motivation in the first years of their courses. While students have little or no contact with advanced disciplines, it is very difficult to attract their interests and encourage them to develop the skills in their undergraduate courses. This work aims to achieve these objectives through a mini-factory project involving the construction of a production line of ceramic tiles on a laboratory scale, from the ceramic processing using raw materials to the shipping of the final product. Having been given an established monthly demand for ceramic tiles, the students determined the construction requirements of the mini-factory, as they have created the layout, including the processing equipment, the dimensioning of equipment, and its operational structure. This article intends to describe the successful creation of the ceramic tile mini-factory, including the objectives, benefits, and inherent difficulties of the process and the receptivity of the exercise by the students involved.

Contribution of electrical parameters on the dynamical behaviour of a nonlinear electromagnetic damper

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)