Analysis of geomagnetically induced currents at a low-latitude region over the solar cycles 23 and 24: comparison between measurements and calculations

Geomagnetically Induced Currents (GIC) are a space weather effect, which affects ground-based technological structures at all latitudes on the Earth’s surface. GIC occurrence and amplitudes have been monitored in power grids located at high and middle latitudes since 1970s and 1980s, respectively. This monitoring provides information about the GIC intensity and the frequency of occurrence during geomagnetic storms. In this paper, we investigate GIC occurrence in a power network at low latitudes (in the central Brazilian region) during the solar cycles 23 and 24. Calculated and measured GIC data are compared for the most intense geomagnetic storms (i.e. −50 q- exponential Tsallis distribution fits the calculated GIC frequency distribution for more than 99% of the data. This analysis provides an overview of the long-term GIC monitoring at low latitudes and suggests new insight into critical phenomena involved in the GIC generation.