Combined TACS-MODELS for Footing Tower Resistance considering ground ionization

Abstract

Voltages produced by atmospheric discharges are considered the main causes of electric power outages. The study of atmospheric discharges should be analyzed and studied in order to make good insulator coordination. In this context, Footing Tower Resistance (FTR) is a crucial parameter in lightning strokes studies. FTR performance is variable with the time, thus their value is not constant. Therefore, it is necessary to visualize the impedance change when a lightning hits overhead lines. This paper presents a model implemented using Transient Analysis of Control Systems (TACS)-MODELS to determine the impedance value considering their non-linear performance. Taking the impedance value equation and considering the current value, the FTR value is estimated during contingency simulation. The model considers a threshold current value for ground ionization phenomena initiation. Results show that the proposed model is effective, emulating with high precision the non-linear ground resistance behavior.