Combined TACS-MODELS for Footing Tower Resistance considering ground ionization

MORALES, JOHN; ORDUÑA, EDUARDO A.; CABRAL, R.J.; BRETAS, A.S.

Simposio; 2014 North American Power Symposium (NAPS); 2014

Voltages produced by atmospheric discharges areconsidered the main causes of electric power outages. The studyof atmospheric discharges should be analyzed and studied inorder to make good insulator coordination. In this context,Footing Tower Resistance (FTR) is a crucial parameter inlightning strokes studies. FTR performance is variable with thetime, thus their value is not constant. Therefore, it is necessary tovisualize the impedance change when a lightning hits overheadlines.This paper presents a model implemented using TransientAnalysis of Control Systems (TACS)-MODELS to determinethe impedance value considering their non-linear performance.Taking the impedance value equation and considering the currentvalue, the FTR value is estimated during contingency simulation.The model considers a threshold current value for groundionization phenomena initiation.Results show that the proposed model is effective, emulatingwith high precision the non-linear ground resistance behavior.