Laboratory investigation on lightning flashes to high voltage transmission lines

This paper presents an investigation on factors, which have an impact on the incidence of lightning flashes to transmission lines. The investigation was performed by the method of laboratory experiments using model tests at the Mississippi State University High Voltage Laboratory. For laboratory experiments, negative and positive switching impulses were applied to a conducting rod, which represented a lightning downward leader. Different tested models of transmission lines in a scale of 1:100 were used. The effect of overhead ground wires, tower structures, and the magnitude and polarity of lightning strokes were studied. According to experimental results, the lightning attractive distance gradually increased with the height of ground wires and towers as well as the magnitude of lightning stroke current. Impulse polarity also had an impact, and the attractive distance for negative polarity was larger than that for positive polarity. Taller towers had more contribution on flash distribution to transmission lines than shorter ones.