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 Autor "Almeida, Carlos Frederico Meschini"

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    Modelagem de cargas harmonicamente acopladas para o sistema elétrico
    (Universidade Federal do Espírito Santo, 2018-01-09) Brunoro, Marcelo; Fardin, Jussara Farias; Encarnação, Lucas Frizera; https://orcid.org/0000-0002-5842-4047; Vieira, José Luiz de Freitas; Salles, José Leandro Félix; Costa, Wagner Teixeira da; Almeida, Carlos Frederico Meschini
    Modeling of electrical systems is important to allow carrying out several studies aiming at reducing losses and improving energy quality, among others factors. In the current scenario, performing harmonic analyses has become necessary due to the increasing insertion of nonlinear loads in the system. Since the voltage and current profiles of the networks are strongly affected by the load behavior, their modeling is essential to carry out such analyses. Differently from the other harmonic models found in the relevant literature, this thesis presents two new proposals for load modeling. The first proposal combines the ZIP model and a cross admittance matrix. This combination brings together the benefits of load characterization using the traditional ZIP model, which provides some physical knowledge about the load, as well as the frequency crossing given by an admittance matrix. In this case, ZIP coefficients are intended to be limited in order to identify the power ratio in terms of constant impedance, constant current and constant power. In addition, we discussed the method for determining the model parameters, using exhaustive search and multiple linear regression. In the second proposal, the new model is based on a circuit that aggregates components of impedance, current and power, in a configuration different from those found in the relevant literature. Coupling between various harmonic orders is provided by a constant current matrix. The multiple linear regression method is used to determine the model parameters. Aspects related to data selection and number of samples are addressed in both proposals. In both cases it was possible to accurately determine the harmonic injection in the load bus, by understanding its voltage supply. Case studies with a real load, using data obtained with a power quality meter, exemplify the application of the models in an electronic load. Several other case studies were implemented using electromagnetic transient simulator software to demonstrate the effectiveness of the proposed models in different loads. In one of these studies, the proposed methodology was applied for the harmonic modeling of a set of loads connected to a radial network. The results obtained in the study of the experimental load, as well as in the other case studies, showed that the proposed models were able to represent the harmonic behavior of the evaluated loads with high accuracy. Keywords: Load modeling. Harmonic load modeling. Electrical power system. Parameter estimation.