FDTD simulation of back-flashover at the transmission-line tower struck by lightning considering ground-wire corona

In this paper, we have simulated back-flashover at transmission line tower struck by lightning in the presence of corona emanated at the ground wire. In the simulations, three two-circuit 60-m high towers, separated by 400 m, with two overhead ground wires, and six phase conductors (two three-phase circuits) are employed. A simplified (engineering) model of corona discharge is applied to the analysis of transient voltages across insulators of transmission line. Back-flashover is assumed to occur at upper-, middle-, or lower phase. On the basis of computed results, the effect of corona space charge emanated from ground wires on transient voltages across insulators in the presence of back-flashover is discussed.