Engenharia Elétrica Telemática
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Navegando Engenharia Elétrica Telemática por Autor "Coelho, Roberto Francisco"
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Monografia Acesso aberto Diagnóstico em transformadores de potência através de ensaios em campo(2012) Sousa, Ismael; dos Santos, Rafael PauloTransformers are vital elements in the electric power systems. Its eventual failure is commonly associated with several problems on the power system and their consumers. Thus, it is necessary to study techniques for diagnose faults in such equipment, avoiding unexpected failures. Initially, this paper discusses about the theory necessary for understanding how a transformer works, emphasizing the power transformers, whose tests are achieved for improving their performance and reducing possible failures. Some field tests, accomplished in order to detect failure in power transformers are detailed, targeting from small problems to hard faults. In addition, these tests may determine the extension of the breakdown on the device under analysis. The results obtained from field tests are commonly employed as parameters to decide if the power transformer returns to operation or not. A case of study is presented for validate the applicability of the field tests on the power transformer failure detection.Monografia Acesso aberto Sistema de microgeração fotovoltaica(2011) Bernd, Ícaro; Tomaz, Rafael AdelinoThis work consists on the study, design and simulation of a DC/AC converter for connecting a photovoltaic array to main grid. It is accomplished by a maximum power point tracker system and a single-phase voltage inverter, operating with three-level SPWM modulation. In the proposed system, two variables are controlled: the output inductor current, in order to obtain low total harmonic distortion and consequently high power factor, and the DC input bus voltage. For achieving the proposed aims, the study begins by a brief introduction about the photovoltaic history and by an analysis concerning the physical and mathematical concepts necessary for understanding the system operation. Furthermore, the system power stages and a detailed analysis of the two employed control loops are also presented. Finally, simulation results are used for validating the theory.Monografia Acesso aberto Smart Grid: os primeiros passos para implantação do conceito no Brasil(2012) Espindola, Bruno Filippe; Demoro, Luciano PedroCurrently, new electrical equipments reach the residences around the planet, whose access is only possible due to the expansion of the generation and distribution electrical system. It is important to emphasize that the Brazilian power system is out of date, remaining based on concentrated generation through large plants. Although in Brazil the electricity generation system is predominately composed by renewable sources, it is necessary to invest in distributed generation, located near the consumption centers. The Smart Grid concept will allow the implementation of distributed generation, improving the power system control, planning, operation and bidirectionality, thus, the consumer will be able to provide active power to the system, when needed. This work consists in to analyze how the Smart Grids may impact on the Brazilian power system as well as, the applicable standards and legislations and the current Brazil situation in front this new technology, where, in order to perform some real information, LIGHT S.A, COPEL, CEMIG and CELESC S.A , were explored.