One-port nonlinear electric circuit for simulating grounding systems under impulse current

• One-port electric circuit for simulating linear and nonlinear behaviors of power grounding systems.
• Circuit parameters obtained from real scale models experiments.
• Similarity between simulated and experimental results of more than 90%.

A one-port nonlinear electric circuit to simulate grounding systems behaviors under high impulse currents is presented. The circuit is based on Loboda's and Pochanke's equations, which describe nonlinear behaviors of soil ionization phenomena. One of the major features of this nonlinear circuit is the possibility to simulate both ionization regions (linear and nonlinear) as a complete grounding system, in commercial simulation software such as Pspice, WorkBench®, ATP or EMTP. In order to determine the linear and nonlinear circuit parameters, two known impulse current curves i(t) were applied on scale models and the corresponding impulse voltages U(t) were measured. From these circuit parameters, the U(t) × i(t) experimental curves were compared with one-port simulated results and the similarities, evaluated using the Area Under Curve (AUC) method, varied in the range 92–99%. In order to compare simulations with experimental data, a field circuit was elaborated to test three experimental scale models using single rods of different lengths.