ARAÚJO, F. J. L.; http://lattes.cnpq.br/2043306930186654; ARAÚJO, Felipe José Lucena de.
Abstract:
In this work, an experimental assessment of a ground grid behavior when
subjected to impulsive currents was performed, both in the time and in the frequency
domain, analyzing transient impedance and pulse impedance (time domain), and
harmonic impedance (frequency domain) relative to the front time, fall time and
amplitude of the current injected into the ground grid under test, in order to evaluate its
quality under high frequency applications, and also validate the obtained results by
using computer models in the time and frequency domain. For this purpose, four
different pulse generator settings were used, resulting in four distinct impulsive current
wave forms, wherein each wave form was injected into 3 different amplitudes.
The results showed that when the analysis variable was the injected current
amplitude, the impulsive impedance had no significant variation. It was also shown that
when the analysis variable was the front time of the applied current signal, the
impulsive impedance varied inversely proportional to the front time of the applied
current signal. When the harmonic impedance module related to the three impulsive
current amplitudes injected was analyzed, it was concluded that: the harmonic
impedance module had no significant changes compared to the injected current
amplitude, to the current waveforms with the same front time. When the harmonic
impedance module related to the four waveforms was analyzed, it was observed that: for
all studied cases, the harmonic impedance module is constant for frequencies below 100
kHz and, above this frequency, the module had its value increased, reaching its highest
value at around 1 MHz. The phase of the harmonic impedance had no significant
changes compared the amplitude of the injected current. When we analyzed the phase of
the harmonic impedance with respect to the waveforms observed that electric grounding
is predominantly inductive behavior.
