Navegando por Assunto "Experimentos em campo"

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Acesso aberto (Open Access)
Desenvolvimento e implementação de gerador de surto e sua aplicação na análise numérico-experimental do comportamento transitório de sistemas de aterramento elétrico.
(Universidade Federal do Pará, 2015-09-21) ARAÚJO, Ramon Cristian Fernandes; OLIVEIRA, Rodrigo Melo e Silva de; http://lattes.cnpq.br/4768904697900863
In this work, the design and construction steps of a voltage surge generator are detailed based on established international standards (IEC 61000-4-5). The waveforms of the two output signals implemented are representative of surges due to the first and subsequent lightning strokes, respectively. Also, their parameters meet the requirements imposed by the standards IEC 60060-1 and IEEE Std-4. In order to validate the surge generator, it was analyzed the transient and steady-state behaviors of several grounding systems when subjected to lightning strokes, using the developed generator as the source of the injection signal. The grounding systems were analyzed by field experiments, and each experiment was reproduced numerically using the FDTD method. Low percentage errors were obtained between the signals measured during the field experiments and the corresponding numerical signals. Moreover, the analyzed grounding systems behaved as expected in literature. Those two facts validade the surge generator built in this work.
Acesso aberto (Open Access)
Estudo experimental de transitórios eletromagnéticos em sistemas de aterramento elétrico devidos a pulsos de descargas atmosféricas
(Universidade Federal do Pará, 2015-05-29) CARVALHO, Lorena de Fátima Pinheiro de; OLIVEIRA, Rodrigo Melo e Silva de; http://lattes.cnpq.br/1450994881555781
In this dissertation, we present a study on the transient and steady-state behaviors of grounding systems when subjected to surges with the waveform of a lightning discharge. The analyses of grounding systems were made using data obtained through experiments conducted in the field and numerical simulations based on the finite-difference method applied to solve Maxwell’s equations in the time domain. In numerical simulations, the experimental setup (rods, cables, resistor and injected signal) and the electromagnetic parameters (conductivity, permittivity and magnetic permeability) of soil and vacuum were modeled numerically. There was good agreement between the measured signals during the experimental tests and their respective signals obtained numerically. This agreement between measured and simulated transient signals was obtained by taking certain technical precautions when designing the experimental setup. Such technical precautions, which are usually not explicitly mentioned in technical literature, are properly addressed and discussed in this dissertation.