Impulse Characteristics of Ground Electrodes in Low Resistivity Soil

Soil properties have been known to be the factors that influence the ionization process in soil, which cause the impulse impedance, Z(impulse) to be lower than that at steady state resistance, R-DC. Many studies have established the relationship between the percentage reduction of Z(impulse) from R-DC in such that the percentage reduction is more pronounced in high resistivity soil, or in high R-DC, than that at low resistivity soils. Nevertheless, Z(impulse) is not the only parameter in representing the characteristics of soil under high impulse conditions, where from the voltage and current waveforms, the current rise and discharged times can also be established, where more accurate and extensive analysis of the electrical characteristics of ground electrodes subjected to high impulse currents can be achieved. This paper presents the experimental results of four ground electrodes, installed in agricultural land, with soil resistivity, of below 3 Omega m, subjected to high impulse currents, where the parameters of current rise times, Z(impulse) and current discharged times were investigated. Two of these ground electrodes are having close R-DC values, despite having different electrode's configurations, were also investigated. (c) 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.