Lightning Surge Analysis of a Transmission Line Tower With an XLPE Power Cable and Metallic Cleats Using the FDTD Method

A direct lightning strike to a transmission line tower may cause overvoltages and insulation failures, and to avoid unexpected insulation failures and protect power equipment, it is necessary to install effective lightning protection measures. To design effective countermeasures, the prediction of lightning surge phenomena is required. The finite-difference time-domain (FDTD) method, one of the full-wave numerical approaches, which do not require the assumption of the transversal electromagnetic mode, has been an effective tool for predicting electromagnetic transient phenomena in 3-D structures, such as transmission line towers. In this article, using a technique for representing coaxial cables in the FDTD method, we simulate a reduced-scale model of a transmission line tower with a power cable, calculate the surge phenomena in the tower model when a surge current is injected into the top of the tower, and compare the FDTD results with the measured results for validation. Furthermore, we propose a technique for simulating the influence of using metallic cleats to fix a power cable to a transmission line tower for FDTD simulations in a 3-D arrangement, and we calculate surge phenomena in practical cross-linked polyethylene power cables placed over a ground plane and installed in a real-scale 77 kV transmission line tower. The FDTD results are validated through the comparison with measured results obtained in a previous study.