Mahmoud Eshagh Ahmadi - Vahdat Institute of Higher Education, Torbat-e Jam, Iran
Mohsen Niasati - Department of Electrical and Computer Engineering, Semnan university, Semnan,Iran
Mahmoud Bargharar-Roudi - Vahdat Institute of Higher Education, Torbat-e Jam, Iran

Lightning is the main cause of low reliability in overhead transmission lines. Studies show that the most power transmission line outages caused by lightning. Often exposure of shield wire, reducing tower footing resistance, and line arrester is used for improving the performance of transmission lines against lightning strike. Upper shield wire in presence lower shield wire has been considered for lightning protection. EGLA and insulators distance dependent on the number of EGLA in the tower. Hence, EGLA with external fixed gap due to the rings at it’s gap terminals is located in different phases of the tower in parallel with the insulators that has been struck by lightning. This minimum transverse distance simulated with EMTP-RV software and determined using disruptive discharge voltage equation in the IEC 60060-1 standard. Eventually, after downstream shield wire evaluation, the minimum distance between this two transmission line equipment is determined by try and error for preventing transverse discharge phenomenon is caused by the proximity effect of the discharging ring of the line arrester.

Lightning; Line arrester; EGLA; transmission line; EMTP-RV