Usually the crosstalk or field to wire coupling mechanisms in multiconductor transmission lines (MTL) are studied considering lumped loads or devices connected at the line terminations (at source and load ends) or as shunt load to ground along the lines, as seen in conventional power system networks e.g. [1-3]. However there are practical systems, e.g. in typical Swedish railway systems, wherein discrete devices exist in series with the line (booster transformers) or in shunt between the lines (auto transformers and track circuits). With lightning transients various parameters that influence crosstalk in MTL systems, such as the ground conductivity, have been analyzed e.g. in .
We shall present various cases of crosstalk mechanisms when the devices are connected either in series with the line or in shunt between the lines. The method used for simulating the voltage and current pulse propagation along the MTL systems is the FDTD method  in conjunction with the recursive convolution proposed in  for inclusion of ground losses. The passive series components connected along the MTL are simulated by the circuit solver ATP/EMTP [6, 7]. Emphasis will be given to present the model that connects the FDTD routine with the circuit solver in a more efficient way. The currents entering or leaving a given type of component at a given position along the lines are modeled as time dependant current sources in the circuit solver and the terminal voltages appearing in the circuit are returned to the FDTD routine as node voltages.
We shall also present the efficacy of the proposed method and mathematically discuss the validity of the present work. The influence of finitely conducting ground on the current pulse propagation is also included in the analysis. From the crosstalk analysis it is also shown that the series connected passive devices cannot be disregarded as they largely influence pulses propagating on the lines in the event of transient phenomena due to lightning or switching. This study could be beneficial for future practical studies of surge protection and insulation coordination.
European electromagnetics (EUROEM), 2008. Lausanne. July 21-25 2008