A comparative study on the shielding effect of tree, concrete building on direct lightning strokes to medium voltage distribution line

Lightning overvoltages are responsible for the majority of faults and outages that occur in Medium Voltage (MV) distribution networks. The overhead lines can be protected from the above phenomena with adequate installation of surge arresters and shield wires. Insulation enhancement can also play a significant role in minimizing outage rates of the lines, though it will not be so effective. However, high and grounded structures such as trees or buildings will naturally protect the lines from direct lightning strokes, if adequate clearance between the lines and the structures is considered. This paper presents the experimental study and electro-geometric modeling on the shielding effect of trees on direct strokes to medium voltage distribution lines. The shielding effect of a nearby tree on an MV distribution conductor is compared with that of a concrete building which has been previously investigated in the literature. It is expected that the results of the comparison will serve as good recommendations for the enhancement of lightning protection in power distribution circuits.