Measures to Suppress the Overvoltage of Low-Voltage Circuits Caused by Lightning Strikes on Communication Tower in Electric-Supply Stations

Inhalt:
This paper describes the results of injecting an impulse current simulating a lightning strike into the top of a communica-tion tower at a electric-supply station and measuring the surge voltage entering the low-voltage circuit. The facility tar-geted in this study is electric-supply station that have experienced insulation failures on low-voltage circuits in the past due to lightning strikes on communication towers. In addition, a method to reduce surge voltages in low-voltage circuits by arranging the grounding structure of the electric-supply station include: To equalize the current flowing through the four tower legs and the building wall, To reduce the current flowing through the building grounding wire, To suppress the ground potential difference that occurs between the transformer for the on-site power supply and the building ground was studied and empirically verified. As a result of the experimental verification, we have confirmed that each method was expected to be effective in reducing the surge voltage generated in low-voltage circuits.