and, therefore, in the case of transient analysis, a variable function of time.
The own resistance of the earthling network, considered to be constant in the time in previous papers, is computed, in the present model, through the use of an algorithm, which is based upon the "Korsunchev similarity approach" [6], [7].
The analysis of the equivalent lumped-constants
network, through which the protection system is simulated, is effected through the use of SPICE. In this analysis each branch of the system is divided in a suitable number of elements, in order to take into account the propagation phenomena. The distributions of the currents due to the stroke upon a point of the structure are put into evidence and subjected to analysis. Finally the influence of the ground resistivity upon said distributions is examined.