Abstract— When an overhead Transmission line is energized, transients overvoltages are generated in the electrical networks including the line and the supply network that can be dangerous and may lead to insulation failure. Therefore, it would be of great importance to study these overvoltages and the different factors affecting on it and the different methods and techniques used to reduce these overvoltages and its undesirable effects. In this paper, the overvoltages due to energization of a typical Egyptian 500kV single line from A_Mousa to Taba are investigated. The effects of the various parameters on the switching overvoltages are analyzed. The power system under study and its components are simulated using ATP/EMTP software package. The statistical distributions of the switching overvoltages for the different cases under study are derived. The techniques of mitigation for the switching overvoltages by shunt reactors, pre-insertion resistor, surge arrestors and point on wave controlled switching are demonstrated.