New type lightning protection schemes of substation incoming lines and their simulations

Lightning failures on incoming lines have serious impact on the safety of power substation. In some mountain areas, where the lightning activity is strong and the soil resistance is high, it is difficult to have its enough efficiency in taking traditional protective measures against lightning discharges. Two new protection measures of incoming lines are proposed and analyzed in this paper: line ZnO arrester and coupling grounding wire. Rationally installed ZnO arresters brings about both safety and economical effect on the protection of incoming lines. The coupling grounding wire is installed under the phase conductor. The electromagnetic coupling effects are improved because of coupling ground wire. The electromagnetic transient calculations are made to analyze these two measures´ protective effects. According to the results of simulation, the over-voltage on the equipments is reduced significantly with the installation of line arrester. And the coupling grounding wires improve lightning protective level effectively. The computational methods are introduced and the results are compared.