Study on induced voltages on an aerial wire due to a current flowing through a grounding grid

摘要

Recently, the operating voltages of low-voltage control circuits on power plants and substations have become lower due to the installation of digital-control equipment. This significantly increases the risk of faults and malfunctions of the circuits due to overvoltages in the control circuits induced by lightning and switching surges. Consequently, the prediction of such induced voltages is required to protect the circuits properly In this paper, we calculate ground-potential rises of a grounding grid with respect to a voltage-reference wire and induced voltages on a control wire above the grounding grid using the FDTD (Finite Difference Time Domain) method, when a lightning current flows through the grounding grid. The calculated results are compared with those measured using a test system composed of the grounding grid and the control wire for validation purpose.