Behaviour of grounding loop with bentonite during a ground fault at an overhead line tower

The results of a single-phase short-circuit experiment at a 35 kV overhead line are presented. During the experiment, the grounding loops, backfilled with bentonite and waste drilling mud, were exposed to real ground fault currents. As a consequence of the increased thermal stresses of bentonite and waste drilling mud, only short time increases of the resistance of the grounding loops were registered. It is shown that, independently of the manner of the neutral point grounding in 35 kV and 110 kV networks, as a backfill material, bentonite retains its positive characteristics even after being exposed to real ground fault currents