Transient impedance of grounding rods

The aim of this paper is the correlation of the transient impedance and its parameters with the stationary resistance of simple grounding systems. Impulse current tests of the standard form 8/20 μs were performed on several types of equilateral triangles and single driven rods of different lengths. The injected current in the grounding system and the developed potential were recorded, resulting in the determination of the time variation of the transient impedance. Further mathematical analysis of the experimental results led to simple linear relations between the parameter of transient impedance and the stationary resistance. The results provide useful information for the design of a grounding system and the measures for the protection of installations from lightning strokes