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Item Aplicação do mapeamento conforme no cálculo do fator de Carter(Universidade Federal de Goiás, 2008-06-06) CALIXTO, Wesley Pacheco; BRITO, Leonardo da Cunha; http://lattes.cnpq.br/6660680440182900; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643The present work proposes a numeric formulation for the determination of Carter's factor as a function of the geometry of the slot of electric machines. This task is made by the use of the Schwarz-Christoffel transformation. In order to reach the objective, there is the need to calculate the Schwarz-Christoffel inverse transformation. This represents a non-linear optimization problem. Therefore, it is proposed a methodology to calculate the parameters of the Schwarz-Christoffel inverse transformation using genetic algorithms. The assessment of Carter s factor is achieved considering polygonal domains with many vertices. The transformation leads to a rectangular domain approach. Moreover, some case studies are proposed and the methodology results are compared to traditional formulation results for the Carter s factor, yielding some disparities.Item Aplicação da Tecnology Readiness Index para definição de escopo em projetos de automação(Universidade Federal de Goiás, 2009-06-27) CASTRO, Marcia Inocencio de; GUEDES, Leonardo Guerra Rezende; http://lattes.cnpq.br/9989795822168281The study of behavior adoption products and services - based technology by the consumer is as a great helper choices for design projects and in targeting market, represented a challenge for new products and technological services therefore means intensive growth of these products, various studies indicate also the frustration of consumers interact with technology acquired. Such evidence are particularly important as consumer beliefs are positively related to your acceptance or resistance in adopt products and technological services. In this context, the readiness to technology emerges as construct fundamental to understanding attitudes on consumer technology. This work is the general objective to propose a method to help engineers electricians in the design project automation home (AR) based on user profile technology from the analysis of personal characteristics, rather evaluating the propensity of individuals with adopt products and technological services air from drivers and inhibitors mental related optimism, inovatividade, discomfort and insecurity. We use as method technology readiness index (TRIx). With this, this work is useful in engineering project air, leading to a design of a project as close as possible claim preference and characteristic of the user / customer is aimed at greater satisfaction and quality products and solutions offered by ARItem Controle Fuzzy e acionamento a velocidade variável de sistema resfriador de leite(Universidade Federal de Goiás, 2010-06-17) CHAVES, Eric Nery; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643This work presents the application of control techniques to drive single-phase induction motors with the aim of improving the performance of cooling systems. The control system is based on Fuzzy Logic and is applied to a three-phase PWM inverter adapted to drive singlephase motors with volts per hertz technique. The main feature of the work is to control the temperature of the cooling system driven by a hermetic compressor using variable speed. A commercial milk cooling system is used to obtain the results.Item Reconhecimento Automático de Aves da Família Tinamidae Através da Vocalização(Universidade Federal de Goiás, 2012-04-11) CONCEIÇÃO, Paulo Francisco da; MACHADO, Paulo César Miranda; http://lattes.cnpq.br/8831309316416795This work presents a comprehensive approach to develop a system for recognizing birds by vocalization. The approach specifically addresses the recognition of birds of the Tinamidae family proposing the analysis of data related to the frequency and song of the bird and also classifying and determining the species of bird. The study differs from related research primarily for performing the pre-processing stage automatically. This stage determines the following characteristics: the minimum, the maximum and the stronger frequencies. It s still made a segmentation of the bird singing in periods of sound and silence. The time of singing is also used as a characteristic peculiar to each species analyzed. For the automatic determination of the characteristics of the frequency and song of the bird, an analysis of the power spectral density was made for each time period specified in the frequency using the spectrogram of the song. The recognition and classification technique adopted was the nearest neighbor, using Euclidean distance normalized by the standard deviation. The accuracy of the technique used was 94.12%.Item Operação do gerador de indução em conexão assíncrona com a rede monofásica(Universidade Federal de Goiás, 2010-03-26) LIMA, Nelio Neves; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643This text reports the effort to present a proposal of a power generation system based on cage rotor Induction Electrical Machine associated to a sinusoidally-switched PWM (Pulse Width Modulation) frequency converter responsible for maintaining constant 60 Hz frequency at the generator leads. DC side at the PWM converter is nonsynchronously connected to a single-phase utility line by means of a full-bridge current-fed thyristor inverter, employing a step-down DC-DC converter in order to turn the grid injected current into a sinusoidal waveform. The proposed system allows for the operation as cogenerator in sites fed by single-phase utility net where there is availability of energetic resources. The DC capacitor voltage (Vdc) is controlled through the DC side energy balance adjusting the amplitude of the active current sent to the utility grid. The control strategy employed was the analogic proportional-integral (PI) error compensation. The system is also able to act as reactive power compensator to the AC loads as the Cdc capacitor represents a voltage source to the inverter and the three-phase diode bridge allows for bidirectional power flow between AC and DC sides. Simulation and experimental results has corroborated system viability to provide three-phase balanced regulated voltages complying with ANEEL 505/2001 Resolution and with IEEE Std 519-1992.Item ANÁLISE ECONÔMICA E BALANÇO ENERGÉTICO DO BIOGÁS EM GRANJAS DE SUÍNOS(Universidade Federal de Goiás, 2009-02-10) LIRA, João Carlos Umbelino; MARRA, Enes Gonçalves; http://lattes.cnpq.br/8463332056679918This work presents a case analysis of energetic harnessing in a piggery, based on the use of biogas generated from pig sewage. The analysis shows that the energy from the biogas produced in the farm processes can be partially used through Clean Development Mechanisms (CDM) in order to improve the system efficiency. The utilized process presents environmental and economical benefits as carbon emissions are reduced and their credits can be traded. Moreover, an economic analysis of alternatives for biogas use was carried out taking into account technical, environmental and financial aspects. The case study was realized on a piggery farm in the south-west of the Goiás State where the economical viability of each of the presented alternatives was analyzed considering the following: total burning of biogas; generation of electrical energy; heating; or the combined heat and power generation (CHP).Item Avaliação de desempenho de medidores monofásicos de energia elétrica dos tipos eletromecânico operando com cargas não-lineares(Universidade Federal de Goiás, 2010-03-05) PINHEIRO NETO, Daywes; MACHADO, Paulo César Miranda; http://lattes.cnpq.br/8831309316416795This work analyzes the performance of single-phase and three-phase power meters, of the electromechanical and electronic types, when they are working with linear and nonlinear loads present in residence, commerce and industry. It differs from related studies mainly for making use of actual loads encountered in day-to-day, rather than sources of electronic charges as has been observed in another papers. The comparison of results is made taking as standard a meter power of high precision developed through virtual instrumentationItem Avaliação dos Impactos da Impedância de Falta e da Geração Distribuída em Estudos de Afundamentos de Tensão(Universidade Federal de Goiás, 2009-09-21) RAMOS, Alessandro Candido Lopes; LEBORGNE, Roberto Chouhy; http://lattes.cnpq.br/3938003534716565; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643This work presents an impact analysis of the fault impedance and distributed ge- neration on the amplitude and annual average quantity of voltage sags in sensitive end-users. Phase-to-ground solid and non-solid faults were simulated in 62 transmission lines at 230, 138, 69 and 13.8 kV, which made part of the electrical system of the municipality of Goiânia, the capital city of the Goiás State, Brazil. For each fault position, a resistive fault impedance was considered. This impedance was considered equal to 0, 2, 5, 10, or 15 or even random. In this case, each one of the mentioned impedance values has a specific probability to occur. The voltage-behind-reactance synchronous machine model was used to model the distributed generation units. The analysis here described is based on simulation results obtained through the Fault Position Method in combination with the Monte Carlo Method. The faults were si-mulated through a frequency-domain fault simulation software called ANAFAS. In order to overcome some limitations and increase the flexibility of the simulation tool, a computational program, called ANAFAS-GUI, was developed in Java language. This program allows the automatic simulation of several cases, with different fault characteristics, by running ANAFAS in background mode. The Monte Carlo Method was implemented in MATLAB. Thus, an efficient computational tool has resulted from the combination of the developed computational tools for the purposes of this work. The main simulation results are the tenden-cy and probability density curves of the voltage sags and their classes. From the results it can be concluded that, if the fault impedance is considered as being a random variable, then the predict voltage sags quantity and severity at the sensitive end-user bus are more accurate when compared to the cases in which this impedance is not considered as such. It can also be concluded that, the connection of a distributed generation unit next to the sensitive end-user bus may result in a decreasing of the voltage sags quantity and severity at this bus, depending on the rated power of the unitItem Algoritmo de Policiamento de Tráfego para Redes OFDM/TDMA WiMAX Baseado em Modelagem Multifractal e Cálculo de Rede(Universidade Federal de Goiás, 2011-09-29) SANTOS JUNIOR, Josemar Alves dos; VIEIRA, Flávio Henrique Teles; http://lattes.cnpq.br/0920629723928382The multifractal modeling is more appropriate in describing some features finding in traffic flows in real networks than other models. This work investigates the behavior of the traffic modeling based policing algorithms found in the literature (Leaky Bucket, Fractal Leaky Bucket, Gaussian Multifractal Leaky Bucket) regarding the buffer utilization, the efficiency for the use of buffer efficiency in describing the accumulated traffic (envelope process), packet dropping and data loss (bytes). First, we compare the envelope process of the considered policing algorithms and the proposed algorithm MAPM (Multifractal Arrival Policing Mechanism), with traffic without policing. Next, it was calculated the system loss rate for a finity buffer system with and without policing algoritm. Using the deterministic Network Calculus, it is also estimated the average queue length (backlog) and delay of bytes by applying the concept of the Min-Plus algebra that presents some differences against the conventional algebra. The proposed policing algorithm was applied to a transmission system based on OFDM (Orthogonal Frequency - Division Multiplexing) / TDMA (Time Division Multiplexing Access) system, where it was evaluated the network performance of the considered policing algorithms. Simulations were carried out with real wireless network trace (Wi-Fi) and wired network trace in order to demonstrate the efficiency of the algorithm proposed in relation to policing algorithms in the literature. The simulations shown the efficiency of the MAPM policing algorithm with traces from wired and wireless networks. We also propose the use of deterministic Network Calculus associated to multifractal envelope process to analyze the traffic behavior in terms of delay and backlog before policing algorithms application in the network. Finally we present the results of buffer utilization, link utilization, delay and backlog to a WiMAX system where the policing algorithm MAPM in general shown delay and backlog increasing in the traffic compared with anothers algorithms and low link utilizationItem Efeitos de cargas não-lineares no dimensionamento de transformadores trifásicos de distribuição(Universidade Federal de Goiás, 2012-05-30) SANTOS, Cairo Rezende dos; MACHADO, Paulo César Miranda; http://lattes.cnpq.br/8831309316416795The intense use of solid state converters that use semiconductor in processing electric power of electrical and electronic equipment brings great benefits such as lower cost, greater efficiency and comfort, but also brings disadvantages, because when connected to the distribution system of electricity produced currents distorted relative to the sinusoidal waveform.. Thus also cause nonsinusoidal voltages that produce additional losses in conductors, transformers and also in its own equipment that generated them. In transformers feeding nonlinear loads occur further losses, which increase the temperature and compromising the insulation life. The factors used and internationally recommended in UL 1561-1994 (K-factor) and IEEE Std C57.110-2008 (Harmonic Loss Factor - FHL) to calculate maximum power three-phase transformers operating in these conditions will be objects of comparison. This work, performed in the laboratory with two three-phase transformers connected in the configuration back-to-back, aims to conduct a survey of actual losses in transformers under linear and nonlinear load and also propose a new scale factor that the three-phase transformers feeding these specific charges. Another aspect to be addressed is planning the design of transformers using these factors. The measurements and data processing are performed at low voltages of the transformers and use transducers voltage and current with high accuracy and LabVIEW programming.Item Falhas e defeitos ocorridos em transformadores de potência do sistema elétrico da Celg, nos últimos 28 anos: um estudo de caso(Universidade Federal de Goiás, 2008-08-20) SOUZA, Denise Cascão Poli; RIBEIRO, Cacilda de Jesus; http://lattes.cnpq.br/8998911644222586Power transformers have a fundamental role in an electrical power system, in addition to representing a significant amount of investment required for the implantation of this system. To reduce the costs associated with a transformer s life cycle and to guarantee its reliability and durability, it is essential to monitor its operating conditions, its insulation system as well as the working conditions of its accessories and other components. Therefore, the aim of this work is to study the faults and defects that occur in power transformers of 34.5kV, 69kV, 138kV, and 230kV of Celg s electrical system, the latter being a highly important electric energy concessionaire in Goiás State, Brazil. The results of this study corroborate its contributions to the field, namely, the efficacy of the predictive technique in the maintenance area during the last twenty-eight years (from 1979 to 2007), the characterization of faults and defects during this period, and the presentation of proposals to implement improvements in the predictive technique, in order to reduce the number of interruptions in the electrical power system.Item PROJETO, IMPLEMENTAÇÃO E AUTOMAÇÃO DE UMA BANCADA PARA ENSAIOS DE MOTORES A RELUTÂNCIA CHAVEADOS(Universidade Federal de Goiás, 2009-06-30) TEIXEIRA, Weldon Carlos Elias; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643This work presents a proposal for testing Switched Reluctance Motors, which is feasible by the design and construction of an automated test bench. The test proposal intends to measure phase s resistance; to compute copper loss; to obtain the magnetizing curves for aligned and unaligned rotor and a performance test, which is based on fixing the under test motor rotor speed by a drive machine that is drove by a frequency inverter. The computational automation is restricted in changing the d.c. voltage applied to the under test switched reluctance motor by a programmable sinusoidal voltage source; changing and/or fixing the under test rotation speed of the switched reluctance; changing the semiconductor-switch switching angle; acquisition and processing of the data obtained in the tests. Computational simulations were performed for validating tests results made in an available switched reluctance motor