999 resultados para sistemas de energia elétrica
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In 2004 two trading environment for contracts of purchase and of electricity energy were established, the Regulated Contracting Environment (RGE) and the Free Contracting Environment (FCE). In the first one, consumers can only buy their energy directly from local electricity distribution, and in the second one, consumers can choose their delivery, amount and type of energy that they will burn through bilateral contracts. Thus, before deciding to migrate to the FCE, it is necessary understanding the rules of marketing, the risk involved and the economic viability of the two markets so can determine which environment has more benefits to the consumer. This paper aims to offer tools to support takeover decision of potentially free costumers, who have the option to migrate to market in order to evaluate the benefits and disadvantages of each market. This paper has also considered the new rules of the third rate cycle, where consumers can opt for green tax. The methodology presented is based on calculations of spending with energy and the risk of flag in captive market and free market in one year
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The questions involving environment and society have been increasingly considered into account when companies make business decisions. However many of them have not yet incorporated sustainability effectively in their business plan, sometimes performing only a few external actions and outside their area of expertise. The concept of corporate sustainability is within this context, and therefore the practice of companies consider, the environmental and social issues into their strategies, along with economic issues. This work has as main objective to identify what are the key indicators and related practices of the concept of corporate sustainability that has been introduced in companies on environmental reference of a certain sector of the Brazilian economy. The sector that was chosen is electric power, having enormous significance both in economy, society and environment. The results indicate that the main practice are in the areas of energy efficiency, security and good relationship with its key business stakeholders
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How companies can sell their surplus production capacity of electric power in Brazil? This work was developed from the question presented and focusing on clarification of procedures to enter the Brazilian electricity market by providing basic guidelines based on resolutions by National Agency of Electric Energy, National System Operator procedures and rules of the Assembly of Electric Energy Commercialization. It features subsidy to companies that fit this profile to evaluate the possibility to sell their surplus electricity. The general aim was to analyze the procedures and the necessary steps to make this sale happen. Was developed through a literature review where an overview of the Brazilian electric sector and a case study of a company that has excess capacity of electricity, but doesn’t make its marketing. Resulted in the expected clarification as well as the incentive for companies through the information presented, the entry in this trade since power is still crucial to the country's economic growth and ensure its availability in quantity demanded is a challenge of the utmost importance for satisfactory results are achieved economic development contributing to the progress of our society
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The energy crisis has affected many countries. With the growing warning with the emission in the atmosphere and the lack of resources, the seek for sustainable sources for energy genaration have become even bigger. Some Countries, as Germany, started first in this journey, creating an incentive program to self-generation with renewable sources (wind, photovoltaics, biomass, etc.), giving priority for smaller plants. In Germany the program called EEG started in 2004. In Brazil, since the beggining of 2012, the self-generators did not know how they could be beneficted for self-generation, and self-generation didn't become commun in the country. However, with NR 482, of April 17th, 2012, the parameters were defined, and the self-generator could have a guideline. Therewith, studyies can be redirected for a better knowlegde of the conditions the self-generator will be sujected, in addition to Germany's case as reference to compare with Brazil's case. In this paper these studies are made, focused in wind power (wind turbines) and photovoltaic panels
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The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading
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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
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This paper presents a study based on literature and examples found on literature of the potential of petroleum gas to be used as a primary source to generate electricity. The steady increase electricity demand in Brazil makes desirable an effective use of all available primary sources, combined with this need the momentum of the country with the discovery of the presalt reserves becomes interesting the use of this gas, often wasted, for generating electricity. The electricity generation in this work is illustrated by the cogeneration in oil refining plants that have the combined cycle thermal operation. The ultimate goal is to provide a text to identify the advantages, disadvantages and trends of this type of generation
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Pós-graduação em Engenharia Mecânica - FEIS
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Pós-graduação em Engenharia Elétrica - FEB
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This paper shows the modeling and control of a single-phase full-bridge inverter with high-frequency transformer that may be used as part of a two-stage converter with transformerless DC-DC side or as a single-stage converter (simple DC-AC converter) for grid-connected PV applications. The inverter is modeled in order to obtain a small-signal transfer function used to design the P+Resonant current controller. A highfrequency step-up transformer results in reduced voltage switches and better efficiency compared with converters in which the transformer is used on the DC-DC side. Simulations and experimental results with a 200 W prototype are shown. 1
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O presente trabalho demonstra por meio da estatística descritiva a situação de faturamento de energia elétrica de uma usina de açúcar e álcool da região de Quatá. Com o intuito de avaliar a utilização da energia elétrica da usina, foram descritos os fatores que interferem no uso da energia elétrica, dados pelo fator de carga (fc) e fator de potência (fp). Nesse trabalho optamos pela estatística descritiva, cujo objetivo básico é o de sintetizar uma série de valores de mesma natureza, permitindo dessa forma que se tenha uma visão global da variação desses valores, organizando e descrevendo os dados de três maneiras: por meio de tabelas, de gráficos e de medidas descritivas. Foi elaborada uma planilha com a média de todos os meses dos anos de 2008 a 2010 a partir dos dados fornecidos pela concessionária de energia elétrica. Foi verificado que a empresa é extremamente eficiente, fato verificado durante estes três anos pela avaliação do fator de potência que geralmente foi 1,0. A empresa foi em média considerada racional, pois seu fator de carga calculado foi avaliado como regular nestes 3 anos.
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The availability of the electrical energy, in sufficient quantities and in competitive prices is a crucial factor to the economic development. The trade-in of the excess electrical energy produced in a system of cogeneration can be seen as an alternative to the creation of an additional source of revenues for ethanol power plants sector, besides contributing to the complementation of the Brazilian electrical headquarter with renewable sources. The objective of this study was to evaluate the economic feasibility of the implementation of a cogeneration electrical central using the excess of sugar cane bagasse and selling the excess of electrical energy with prices of the market. An ethanol power plant located in the state of Sao Paulo was used to this study. It was used the case study methodology, evaluating the potential of the investment under the viewpoint of the Net Present Value (NPV), Payback and Internal Rate of Return (IRR), and complementing the results of the Accounting Results (AC). It was created three alternative scenarios to reflect the level of the risk of every studied situation: the most likely, an optimistic and a pessimistic, each one with its assumptions. The Monte Carlo Simulations was used to insert the elements of risk to each scenario. The results showed that the project is feasible in all NPV scenarios. And the Payback and IRR analysis confirmed these evidences. The valuation with the AR showed that the project is most risky at the pessimistic scenario, but is feasibly in the most likely and the optimistic scenarios. It was concluded that the project is economic viable. However, the economic viability shown in the results is based on the maintenance of the future prices on the levels of the historical prices used in the analysis.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Depuis que l'électricité a été découverte et que le secteur électrique s'est considérablement développé dans le XVIIIe siècle, jamais l'homme n'a pu se détacher de cette énergie. Pendant longtemps le système d'énergie électrique a fonctionné sans grand changement, mais avec le développement rapide des technologies, de nouvelles améliorations apparaissent. Ce mémoire traite des nouveaux concepts de réseaux d'énergie électrique appelés Réseaux intelligents ou Smart Grid. À travers un panorama de leurs développements dans le monde, cette étude porte d'une part, sur l'avancée des projets dans quelques pays et d'autre part, du niveau de développement de ce réseau au Brésil et de son intérêt pour le pays. L'étude a comme point central un des composants de ce réseau intelligent, le compteur communicant, qui est l'élément essentiel des interconnexions entre consommateurs et producteurs. Ce rapport apporte un éclaircissement sur les compteurs conventionnels et les compteurs intelligents et sur leur mode de fonctionnement. Enfin il aborde la question des consommateurs : par quels moyens leur transmettre tous ces changements à venir, puisque jusqu'à présent, leur seule participation était de payer l'énergie consommée. Avec le nouveau réseau, ils deviendront de véritables acteurs puisqu'ils seront informés en temps réel de leur consommation d'énergie électrique. Pour terminer, le mémoire montrera comment ils pourront s'adapter à cette nouvelle façon de gérer leur consommation en ésperant les inciter à une utilisation plus raisonnable de l'énergie et à modifier leur comportement en gérant de manière active leur consommation en intégrant notamment les énergies renouvelables