“ANÁLISE DE LINHAS DE TRANSMISSÃO DE ENERGIA EM REGIÕES EQUATORIAIS DURANTE A TEMPESTADE GEOMAGNÉTICA DE 10-11 DE MAIO DE 2024

Abstract

Abstract

ANALYSIS OF ELECTRICAL POWER TRANSMISSION LINES IN EQUATORIAL REGIONS DURING THE GEOMAGNETIC STORM OF 10–11 MAY 2024

Éfren Mota de Souza

October 2025

Geomagnetically induced currents (GICs) represent an increasing risk to the integrity of electrical power systems, particularly high-voltage transmission lines (TLs). Generated by rapid variations in the geomagnetic field, these currents can penetrate electrical networks through grounded neutral points of substation transformers. This study investigates the relationship between electrical parameters from two TLs in northern Brazil, near the magnetic equator, and magnetic parameters from nearby observatories during the severe geomagnetic storm of 10–11 May 2024. In addition, a comparative analysis, restricted to the statistical procedure, was conducted for a geomagnetically moderate period on 24 March 2024. The analysis included current and voltage data from the TLs and magnetic records (H-component) from the Tatuoca (TTB), Kourou (KOU), and São Luís (SLZ) observatories, with emphasis on the influence of the Equatorial Electrojet (EEJ). The temporal derivative of the horizontal component (dH/dt) was used as an indicator of the intensity of geomagnetic disturbances capable of inducing GICs, while Pearson’s correlation coefficient quantified the relationships between electrical and magnetic variables.

The results revealed dH/dt peaks exceeding 60 nT/min at TTB and SLZ, particularly at the sudden commencement of the storm (17:05 UTC), associated with the arrival of a Coronal Mass Ejection (CME). KOU, being the observatory farthest from the EEJ influence, displayed the lowest peak among all. An increase in dH/dt with proximity to the magnetic equator was observed, highlighting the role of the EEJ. A threshold value of 30 nT/min (associated with the risk of inducing GICs) was exceeded multiple times at all magnetic observatories during the analyzed period. Correlations were strong to very strong (r > |0.80|) during the initial and main phases of the storm, and weaker to moderate durin g the recovery phase (|0.39| ≤ r ≤ |0.55|), revealing phase-dependent patterns. Comparison with the moderate period (24 March 2024) indicated similar r patterns between current and H-component to those observed during the initial and main storm phases (r < –0.91), but weak and inverse correlations between H-component and voltage (–0.10 ≤ r ≤ –0.16). Although preliminary, these results emphasize the importance of regional factors in GIC risk assessment and demonstrate the potential of integrating raw electrical TL data with geomagnetic observations for preventive strategies in power systems.

Keywords: Power transmission lines; Pearson correlation; Equatorial electrojet; GICs.