Experiments of lightning induced overvoltages on a real-size overhead power distribution line

The authors produced induced voltages on a real-size distribution line, the height of which is 10meters. A balloon filled with helium gas lifted a 150 meter-long copper conductor near the overhead distribution line. A pulse current was applied to the above conductor. Induced voltages on the overhead distribution line were observed at three points. As the distance between the grounding point of a copper wire and an overhead distribution line becomes large, the induced voltages on an overhead distribution line become small. The induced voltage is the largest at the nearest point to the balloon. As the distance from the nearest point to the balloon on the distribution line becomes large, the peak value of the induced voltage becomes small. Experimental results agree roughly well with calculated results obtained by a numerical analysis.