| Title |
Improvements of Grounding Performances Associated with Soil Ionization under Impulse Voltages |
| Authors |
김회구(Kim, Hoe-Gu) ; 이복희(Lee, Bok-Hee) |
| DOI |
https://doi.org/10.5370/KIEE.2016.65.12.1971 |
| Keywords |
Impulse voltages ; Grounding resistance ; Soil ionization ; R-t curve ; V-I curve ; Ionization development |
| Abstract |
In this paper, electrical and physical characteristics associated with the ionization growth of soil under impulse voltages in a coaxial cylindrical electrode system to simulate a horizontally-buried ground electrode were experimentally investigated. The results were summarized as follows: Transient ground resistances decreased significantly by soil ionization. The voltage-current (V-I) curves for non-ionization in soil lined up in a straight line with the nearly same slope that is the ground resistance, but they showed a 'cross-closed loop' of ∞-shape under ionization. The conventional ground resistance and equivalent soil resistivity were inversely proportional to the peak value of injected impulse currents. On the other hand, the equivalent ionization radius and time-lag to the maximum value of ionization radius were increased with increasing the incident impulse voltages. An analysis method for the transient ground resistances of the ground electrode based on the ionization phenomena was proposed. The proposed method can be applied to analyze the transient performances of grounding systems for lightning protection in power system installations. |