Effects of fulgurites on the earthing system

This paper presents results that demonstrate the effects of fulgurites on the earthing system of a power system. The importance of grounding in power systems cannot be over emphasized. Although studies of fulgurites have been done in the past, no research work has reported on the impact of fulgurites on electrical grounding. The backfill materials used to enhance an earthing system play a pivotal role in controlling ground impedance of the soil by lowering the impedance of the earth. The impedance of the grounding is the sum of the static and dynamic impedance. The results of this work show that the static impedance of the backfill material increased in the event of fulgurite formation. Regarding the soil sample studied from a Swaziland 11 kV feeder, this occurred for lightning impulse currents equal to or greater than 30 kA. Swaziland is a country that experiences frequent power failures due to lightning, especially during the rainy season. It is thus essential to have a sound grounding system that is able to withstand all types of fault conditions and hence, the need for this study. The long-term aim of this research is to characterize a backfill material that will address the performance requirements of the network earthing system.