Transient impedance of grounding rods encased in ground enhancing compounds

The aim of this research work is the correlation of the transient impedance and its parameters with the power frequency resistance of grounding rods driven in ground enhancing compounds. Full scale impulse current tests of a standard form have been performed on single grounding rods driven both into soil and in ground enhancing compounds. The injected current into the grounding system and the developed electric potential on it have been recorded, resulting in the determination of the time variation of the transient impedance. The results provide useful information for the design and the behavior of a grounding system, encased in bentonite and conductive concrete under lightning impulse currents, as well as for the protection measures of installations from lightning strokes.