GONÇALVES, M. F. B. R.; GONCALVES, MARCONNI.; GONÇALVES, M.F.B.R.; http://lattes.cnpq.br/7635381387080045; GONÇALVES, Marconni Freitas Barroso Ribeiro.
Resumen:
In this work, a methodology of evaluation of grounding systems subjected to current
impulses is proposed based on the amplitude and frequency of the impulse, the
configuration of the grounding system and the resistivity of the soil that surrounds the
grounding system. Experimental field tests and computational simulations were
performed on grounding systems subjected to impulse currents with amplitudes between
1 kA and 2.5 kA and front time between ͳͲ μs and ͵Ͳ μs. Field tests were performed for
two different configurations of grounding systems and different electrical characteristics
of the soil. The results in the field were used to propose two models that represent the
grounding system from the characteristic curve of the relation between measured voltage
and applied current (V×I). In comparison to a reference model in the literature, the
proposed models presented greater ease of calculation of their parameters and
implementation with only linear elements. By presenting themselves as a simple and
reliable configuration, the proposed models can be coupled, with greater ease and
flexibility, to programs of electromagnetic transient analysis and in insulation
coordination studies. The results obtained from the field tests were also used to prove
computational simulations performed in XGSLab® software. The simulation of the
grounding system was generalized considering the variation of the input parameters and
the inductive and capacitive effects. As proof of concept, a methodological procedure was
proposed for the grounding systems evaluation capable of identifying the effects caused
by high intensity and high frequency phenomena. The methodological procedure allows
the representation of the performance of grounding systems, through the use of models
obtained from tests, as well as of computational simulations, in traditional programs of
electromagnetic transient analysis.