Experimental performance of induced voltage on power line due to lightning discharge to nearby tree

With continually increasing emphasis on the reliability of power systems, further understanding of the main causes of lightning faults in medium voltage lines is required for effective protection. Lightning-induced voltage on power distribution lines or telecommunication lines has been a subject that has received critical attention in the literature for years. However, very few investigations have been carried out on the influence of very close and tall structures, such as trees, buildings and other high structures on the lightning performance of power distribution lines. Recent measurements have revealed that a tree can intersect a lightning stroke in the vicinity of a power line, but not in all situations. In addition, induced voltage exists even when the power line is perfectly shielded by the nearby tree. This paper presents the results of experimental findings on the induced voltages existing between a lightning-struck tree and a power distribution line. The effects of; tree-to-line clearance, change in lightning time characteristics and polarities on the induced voltages are investigated.