The grounding of a conductor etc. Most of the over voltages are not of large magnitude but may still be important because of their effect on the performance of circuit interrupting equipment and protective devices. An appreciable number of these over voltages are of sufficient magnitude to cause insulation breakdown of the equipment in the power system .Lightning is one of the most significant source of over voltages in overhead transmission lines. The lightning over voltages could lead to failure of the devices connected to the transmission line. Surge arresters are an important means of lightning protection in distribution systems. Therefore, it is necessary to analyze influence of such over voltages in order to applying the line surge arrester for improving the reliability of transmission line system. Determination of the maximum voltages induced on the overhead line by direct stroke is a complex problem. For estimating the flashover due to direct strokes, it is necessary to calculate the maximum voltage induced on the line. The effect of direct lightning on transmission lines have been analyzed with and without the help of surge arrester.