A contribution to the investigation of the shielding effect of transmission line conductors to lightning strikes

The electrogeometric model has been used to calculate the transmission line lightning shielding characteristics. However, actual UHV design transmission line accidents and the lightning observation results indicate that there are differences between what actually happens and theoretical results. In this paper, long-gap discharge tests were conducted to better understand lightning shielding characteristics, mainly of UHV design transmission lines. As far as the test method is concerned, the arrangements of transmission line conductors were reduced, and simulated as ground electrodes, and a switching impulse voltage was applied to rod electrodes. As a result, discharges occurred most frequently to the conductors with the smallest gaps with the rod electrodes. On the other hand, it was seen that the electric field strength of the transmission lines and their position with respect to ground might have some influence. These results might also be valuable for long air gap dielectrics.