Shielding failure analysis of extra high voltage unconventional transmission lines with increased power delivery capability.

Lightning is a natural phenomenon, and extra high voltage (EHV) transmission lines (TL) are prone to it due to the high altitude of EHV towers and lines. Though adequate steps are taken to minimize its effect, many incidents occur where lightning is the main cause of the line outage. On the verge of an era where the distribution and generation sectors are undergoing drastic changes, the transmission line must also modify its design to cope with this wave. In this context, unconventional high surge impedance loading (HSIL) lines emerge as a potential game changer. Various electrical, mechanical, and structural aspects need to be studied to realize a new overhead line. Among them, a question is raised about the performance of these new unconventional HSIL lines against lightning. Especially this paper aims to answer the key question of whether insulation coordination and protective equipment employed for traditional lines is sufficient when using unconventional HSIL lines in addressing shielding failure. To the best of our knowledge, such a study has not been conducted to date.