Joule Heating in Grounding Electrodes Under Fault Conditions: Effects on System Potentials and Electrode Efficiency  
[PERSON]  
Educardo Faleiro  
[PERSON]  
[PERSON]  
[PERSON]  
Educardo Faleiro  
electrical stress due to Joule heating, which can significantly impact their performance and the overall system potentials [1; 2; 3]. Joule heating, also known as resistive heating, occurs when electrical current passes through a conductor, generating heat due to the material resistance. In grounding electrodes, this phenomenon can cause a temperature increase that affects soil conductivity, electrode integrity, and grounding resistance [4; 5]. As temperature increases, the surrounding soil may dry out, reducing its conductivity and increasing the overall ground resistance. This change can compromise the efficiency of the grounding system, potentially leading to higher step and touch voltages that pose safety risks. Under high-current fault conditions, the localized heating of both the electrode and adjacent soil modifies their electrical resistivity, introducing nonlinear temperature-dependent feedback that affects current distribution and voltage gradients. These thermal effects are particularly pronounced near geometric discontinuities such as corners and ends of electrodes, where current density tends to be highest. Over time, repeated fault events or a single high-intensity event may cause the localized degradation or even melting of electrode materials, especially if the thermal response is not adequately considered during design. Previous studies have explored various aspects of electrode performance under fault currents, including analytical and numerical modeling of current dispersion and soil resistivity [6; 7]. However, comparatively few works incorporate the dynamic thermal-electrical coupling that arises from temperature-dependent resistivity, especially in realistic multilayer or heterogeneous soil conditions [8; 9; 10]. The inherent complexity of this coupled process requires numerical approaches capable of simultaneously solving for the evolving thermal and electrical fields. Nevertheless, thermal effects on grounding systems under high fault current have been investigated in some papers. For instance, in references [11; 12; 13], the authors examined the transient thermal response of grounding rods and found that prolonged fault conditions could cause structural degradation due to repeated thermal cycling. Similarly, in [14], [PERSON] et al. highlighted that materials such as copper and galvanized steel experience significant changes in electrical resistance at elevated temperatures, affecting the dissipation of fault currents. Moreover, the interaction between thermal and electrical phenomena in soil has been studied, showing that localized soil ionization and dehydration can lead to an increase in ground potential rise (GPR), further impacting grounding system performance [15]. The heat dissipation and electrical performance of buried conductors under load are discussed in [16; 17]. Finally, the foundational study [18] uses a finite-difference method to model temperature distribution in soil around HVDC ground electrodes. It provides numerical profiles of heat dissipation under continuous current injection. Given the critical role of grounding electrodes in electrical safety, understanding the effects of Joule heating under fault conditions is essential for designing more resilient grounding systems. This study aims to analyze the impact of fault-induced heating on system potentials and electrode performance through numerical simulations and experimental validation. This research focuses on evaluating temperature rise, material degradation, and variations in soil conductivity under fault conditions. The findings of this study will contribute to the optimization of grounding system design and enhance fault management strategies in modern power networks. For this purpose, the present paper is structured as follows.