Back-flashover analysis of overhead transmission lines for different tower and lightning models

Lightning can produce a large number of outages in an electric power system through the back-flashover phenomenon. The paper is devoted to the back-flashover study and analysis of overhead transmission lines using different tower and lightning models. Simulation results were obtained using the EMTP software package linked to external computer routines, which were developed by the authors, converting specified sets of lightning parameters into mathematical functions, avoiding the editing of large text files to represent user sources. Three different functions were created in order to generate concave, double-exponential or triangular wave shapes, with specified lightning current parameters. Different, constant or non-linear, footing resistance values were assumed. Finally, the solutions are compared and some important conclusions to the back-flashover effect in overhead transmission lines are pointed out.