Theory of field-excited networks

The analysis of the transient response of multiconductor transmission line networks excited by electromagnetic (EM) fields can be performed either in the time- or in the frequency-domain. The transient analysis of field-excited networks having complex configurations and nonlinear loads is performed by using a combined frequency- and time-domain procedure. The simulation models of the line-sections are defined in the frequency-domain based on the exact formulation of Maxwell´s equations. New expressions of the per-unit-length (p.u.l.) series impedances and shunt admittances are used in order to overcome the limitation of the Carson (1926) formulation in the case of a poorly conducting ground-plane and in the presence of very fast transients. An efficient procedure is applied for reducing the computation effort of the procedure in the case of complex large-dimension networks. Calculations are carried out to predict the overvoltages induced by an EMP-plane wave on a 20 kV-power network above a highly lossy ground and on a signal 18-port-multiconductor network