Transient investigations on lightning overvoltages applied on oil tanks roof considering grounding configurations

This paper is treated with the lightning overvoltages (LOVs) applied to the roof oil tanks in low voltage distribution systems. Since the oil tanks and electric distribution towers are not usually protected by guard wires, they may be more exposed to lightning strikes. In this way, the grounding system configurations, soil resistivity, the oil tank diameter and even the inherent characteristics of lightning strikes play an important role in the possibility of malfunctioning caused by overvoltages. The simulation results represent that the distance between indirect lightning stroke points discharging to the ground and the oil tank locations can also create destructive LOVs on them, if the grounding system is not well selected and implemented. Power system protection equipment such as surge arresters can greatly reduce these effects, but due to economic limitations, it is not possible to use them extensively and, therefore, it is necessary to limit LOVs using the minimum available facilities like grounding system variation. This paper represents that using meshed grounding systems can better mitigate the corrosion and the hazards of lightning surges than conventional vertical rods with effective length. All mathematical equations and formulations are solved using numerical methods implemented in Fortran.