Software development for the evaluation of the lightning performance of overhead transmission lines

A useful tool for the evaluation of the lightning performance of overhead transmission lines has been developed in Matlab. The software (LPTL) runs as a Microsoft Windows application and features a user-friendly graphics interface. For given overhead transmission line parameters, ground flash density and lightning crest current distribution the lightning performance of the line can be easily evaluated according to several lightning attachment models. Through an application to a typical 400 kV double circuit line of the Hellenic transmission system the effects of lightning attachment model and lightning crest current distribution on the lightning performance of the line are quantified. Generally, electrogeometric models yield the highest shielding failure flashover rate whereas the lowest backflashover rate. As the median value of the lightning crest current distribution increases the shielding failure flashover rate decreases whereas backflashover rate increases. The application software is a useful tool for utilities and can also be used for educational purposes in high voltage engineering courses.