Over the last few decades, the electric utilities have seen a very significant increase in the application of not only for industrial but also for domestic and commercial purpose. With the significant in power generation to meet growing demand, the transmission system has to be augmented to transfer the bulk power generated to the load centre. The general transmission lines gets very much affected by lightening thunder (leader stroke) while working steadily at its normal working period.\\ Lightening effects on transmission line have always been a matter of concern in studies of power distribution, transmission and up gradation of transmission system. The magnitude and shape of the lightening on transmission line will be in undetermined and unpredictable form. It takes place for some microseconds to milliseconds and as it arises (immerges on object), it causes an serious damage to the system where it immerges.\\ The analysis of lightening leader (strokes) arising in distribution and transmisssion system is assuming increased importance. This is mainly because such studies yield neccessary information about the possible damage on different component which will determine their proper design as well as their persistance protection strategies .Height dependent model is universally accepted production Industry standard for both distribution and transmission. In this report general studies carried out to obtain analysis of 220kV/400kV and 765kV transmission line structure models compared them with existing configuration of 220kV/400kV and 765k transmission line.\\ Several parts of an overhead transmission line have to be included in a model adequate for lightning studies. Along with the study about the transmission lines study and their structure analysis. Some calculation has given which explains the protectiveness of given structure . The main purpose of this report is about studying the structure of generalised transmission lines which are existing for comertial Benefits. i.e transmission of huge ammount of energy from source to destination. "Including the protective study of HV (more than 100kV) and EHV(345 to 765kV) lines. "