Effect of Wiring Installation System on Overvoltage at the Distribution Boards of a Building Struck Directly by Lightning

To protect electric and electronic equipment in buildings impacted by direct lightning strikes, surge protective devices are installed at the power substation, between the neutral and earth lines in a TT earthing system. We investigated the mechanism of overvoltage generation at distribution boards and analyzed the flow of lightning currents through the earth lines in the system using electromagnetic analysis. The over voltages were found to be smaller when the power substation was installed at the top floor than that on the first floor. We confirmed that the overvoltage could be suppressed by designing the electric pipe-shaft position at the center part of the building structure.