ABSTRACT
This chapter determines the current and voltage which can be induced on the line due to a lightning stroke in order to optimize the protecting devices. It explores the relative importance of the coupling to the horizontal and to the vertical part of the line. The chapter describes the various approximations which can be used to get an efficient numerical code to determine the electromagnetic field radiated by a cloud to ground discharge. The telecommunication network and telecommunication cables behave as very long interconnected antennas on which the disturbing electromagnetic fields induce currents in a wide frequency range. The experiments are planned at the St. Privat d'Allier triggering station to measure the disturbing surges on other telecommunication lines near the station to compare the measurements to the theoretical results for various positions of the illuminated line with regard to the ground strike point.
