Experimental study of current-dependent grounding resistance of rod electrode

This paper has experimentally investigated transient behavior of grounding electrode systems especially for a high impulse current up to 40 kA in particular reference with a mutual grounding resistance between the electrodes. The experimental results show that the mutual grounding resistance depends on the applied current similarly to the current dependence of the self-grounding resistance. The phenomenon can be explained by the increase of an effective rod radius and an effective length. The selfgrounding resistance greatly depends on the rod dimension and on the soil resistivity for low currents as analytically well known. However, the parameters cause a less effect on the nonlinear characteristic for high currents exceeding 10 kA.