A lightning stroke which reaches a peak current of 30kA in 1S strikes a 25 m tower
Question:
A lightning stroke which reaches a peak current of 30kA in 1μS strikes a 25 m
tower on a 275kV transmission line. The line has a ground wire joining the tops of the towers; its
surge impedance is 500 Ω . The tower surge impedance is 120 Ω and the ground footing
resistance is 60 Ω . Determine whether the line insulators will flashover as a consequence of
the surge, assuming that their impulse flashover strength is 1050 kV. A coupling factor 0.3 with
the phase conductor can be assumed; the impedance of the stroke channel can be ignored; a wave
velocity on the tower of 2.98 x 10^8 m/s can be assumed. Show the surge progressions in the
form of Bewley lattice diagram.
Vector Mechanics for Engineers Statics and Dynamics
ISBN: 978-0073212227
8th Edition
Authors: Ferdinand Beer, E. Russell Johnston, Jr., Elliot Eisenberg, William Clausen, David Mazurek, Phillip Cornwell