Experimental Investigation of Lightning Transients Entering a Swedish Railway Facility

Transients caused by lightning in railway facilities have not received much attention. In this paper, we describe the measurements of lightning transients entering a Swedish railway facility during the summer of 2003. The measurements of the transients were made in a technical house that provides an uninterrupted power supply for telecommunication systems and the signal systems. An analysis of the data has shown that transients in excess of 7 kV (peak to peak) can appear across the line-to-neutral supply system due to an indirect lightning strike. Some typical characteristics of the line-to-neutral transient voltages in terms of stroke locations and stroke amplitudes are presented. Further, from the experimental data, an empirical relation for predicting the line-to-neutral transient voltage in terms of stroke location and stroke current amplitude is obtained. Simple induced voltage calculations are presented to identify the levels of induced voltages appearing at the input of the technical house. The influence of ground conductivity on those induced voltages is also presented. The information presented in the paper is an important electromagnetic-compatibility issue associated with the lightning protection for railway systems