Grid design depends mainly on bringing grounding resistance, mesh voltage, and step voltage below tolerable limits when
subjected to any ground fault. But, it should be noticed that the grid performance has to be tested when subjected to lightning
stroke. The performance of the grid under impulse current differs than that of under power–frequency fault. In this paper
ATP-EMTP software is used to analyze the performance of the ground grid when subjected to lightning stroke. Different
methods are suggested to mitigate the lightning overvoltage, all of these methods depend mainly on modifying the design by
adding more conductors or rods at specific places. The case study under consideration is Al-Mostakbal substation 220/22 kV
which is located in Al-Mostakbal city, Cairo, Egypt. |
