Engenharia Elétrica

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http://repositorio.ufes.br/handle/10/17617
Programa de Pós-Graduação em Engenharia Elétrica

Centro: CT
Telefone: (27) 4009 2663
URL do programa: https://engenhariaeletrica.ufes.br/pt-br/pos-graduacao/PPGEE

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Navegando Engenharia Elétrica por Assunto "628"

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    Análise de um Filtro Ativo em Paralelo com Cicloconversores e Filtro Passivo
    (Universidade Federal do Espírito Santo, 2008-03-25) Ferreira, Célio Geraldo; Sousa, Gilberto Costa Drumond; Simonetti, Domingos Sávio Lyrio; Aragão Filho, Wilson; Rocha, Joaquim Eloir
    In the steel industry non linear loads are frequently used such as cycloconverters for rolling mills. This kind of load influences the power quality of the supply network, resulting in distortion in the system voltage. In order to improve the power quality of the grid, passive filters are commonly used. However, a passive filter can present some drawbacks, mainly when the plant is under expansion or the operating conditions change. These drawbacks of the passive filter can be alleviated by the combined use of active and passive filters, and by appropriately coordinating their operations. That is, of the harmonic currents generated by the cycloconverter, part is absorbed by the active filter, and another by the passive filter. This provides a good harmonic compensation over the entire operating range for the varying spectrum harmonic current frequencies generated by the cycloconverter. This work analyzes a real electrical power supply of a steelmaking rolling mill, in the present conditions, as well as in a scenario of plant expansion. A digital simulation model, consisting of a passive filter, active filter, cycloconverter load and power supply system was developed, followed by a study to investigate the combined use of passive and active filters, mainly to assess their effectiveness to compensate the harmonic components and, consequently, to improve the plant power quality level.
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    Modelagem da dispersão de odores em ambientes urbanos
    (Universidade Federal do Espírito Santo, 2013) Dourado, Harerton Oliveira; Reis Junior, Neyval Costa; Santos, Jane Meri; Albuquerque, Taciana Toledo de Almeida; Nieckele, Angela Ourivio; Harion, Jean Luc; Moreira, Davidson Martins
    The present work investigated odour dispersion modelling in the presence of obstacles (cubical and complex-shaped buildings) under neutral atmospheric conditions employing numerical modelling based on the transport equations (CFD8) as well as on algebraic Gaussian- based models (AERMOD9, CALPUFF10 and FPM11) and using field and wind tunnel data to validate the models results and evaluate the models performance. To include atmospheric turbulence effects on dispersion, two different subgrid scale models associated to the Large Eddy Simulation (LES) technique were investigated (Dynamic Smagorinsk and WALE12) and to include the building effects on dispersion in the Gaussian-based models, PRIME13 was used. The use of PRIME was also proposed for FPM as a novelty. Overall, results indicate the use of the CFD/LES might be a useful tool for assessment of odour dispersion and impact in the presence of obstacles and also for the development of Gaussian models. Results also indicate that the proposed FPM, which included the effects of the obstacle based on the PRIME model, is a very useful tool in odour dispersion modelling, due to its simplicity and easy set up if compared to the more complex CFD modelling and even regulatory models AERMOD and CALPUFF. The great advantage of FPM is the possibility of estimating intermittency and also the peak-to-mean (P/M) concentration ratio, which are useful parameters for odour impact assessment. Results obtained in the present work indicate the determination of the plume segments dispersion parameters, as well as the long term dispersion parameters in the near field of the source and obstacle in FPM might be improved and CFD could be used as development tool for this purpose. Key words: Odour control, dispersion, computational fluid dynamics (CFD), mathematical modelling, fluctuating plume Gaussian modelling, Large Eddy Simulation (LES).