Lightning Current Simulation of 66-kV Substation With Power Cables Using the Three-Dimensional FDTD Method

Lightning currents may cause damage to power equipment in a substation and a transmission line (TL), and thus, to protect power equipment properly, it is required to install effective lightning protection measures on the basis of the prediction of electromagnetic transient phenomena through numerical simulations. In this article, using an electromagnetic transient simulation code developed on the basis of the 3-D finite-difference time-domain (FDTD) method, we simulate a 66-kV TL, 66-kV substation, and 6.6-kV distribution line, and carried out FDTD simulations by modeling a direct lightning strike to the TL tower. First, we study the effect of the lightning current waveform on the lightning currents flowing through the sheath voltage limiters (SVLs) of the power cables installed between the cable sheath and the tower structure and the lightning current flowing out of the substation into the distribution line through a surge arrester (SA) installed between the grounding structure of the substation and the distribution line. Second, we propose a technique for taking into account the influence of the lightning current flowing into the other TL towers via the shield wire for a long-duration lightning current, and we evaluate the effectiveness of some countermeasures to reduce the lightning currents flowing through the SVLs and SA.