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

Abstract

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. À50 < Dst < À50 nT) of the solar cycle 24. The results obtained from this comparison show a good agreement. The success of the model employed for the calculation of GIC leads to the possibility of determining GIC for events during the solar cycle 23 as well. Calculated GIC in one transformer reached ca. 30 A during the ''Halloween storm'' in 2003 whilst most frequent intensities lie below 10 A. The normalized inverse cumulative frequency for GIC data was calculated for the solar cycle 23 in order to perform a statistical analysis. It was found that a 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.

Long‐term geomagnetically induced current observations in New Zealand: Earth return corrections and geomagnetic field driver

“…We focus on the geomagnetic storm from 0 to 6 UT on 2 October 2013, during which Kp reached a maximum value of 8−, the local (to New Zealand) Eyrewell K index peaked at 6 (from 3 to 6 UT), and we have GIC observations from 49 distinct locations (the remaining 7 transformers have no measurements available in that 6 h period). Across this time period the HVDC link was continuously operating in single wire Earth return mode, with currents ranging from ~100 A up to values as high as ~1020 A. GIC modeling and observations from a single location in Brazil during this storm have appeared in the literature [ Barbosa et al ., ].…”

Space Weather Effects Produced by the Ring Current Particles

“…Kappenman 2003;Trivedi et al 2007;Marshall et al 2012;Zhang et al 2015;Barbosa et al 2015;Watari 2015). The presence of the enhanced ring current during storms may be directly related to the GIC generation at these latitudes.…”

Use of spherical elementary currents to map the polar current systems associated with the geomagnetic sudden commencements on 2013 and 2015 St. Patrick's Day storms

“…After the work of Pulkkinen et al . [], SECS have been extensively used to model rapidly varying ionospheric currents with the interest put into the effects they have on technological conductor systems at the Earth's surface due to geomagnetically induced currents (GICs) [e.g., Viljanen et al ., ; Bernhardi et al ., ; Wik et al ., ; Beggan et al ., ; Vanhamäki et al ., ; Caraballo et al ., ; Wei et al ., ; Liu et al ., ; Barbosa et al ., ; Viljanen et al ., ; Juusola et al ., ]. The method can also be used as a means to interpolate magnetic field variations over large areas [ McLay and Beggan , ] and has found its application to reduce geomagnetic repeat station surveys [ Vujić and Brkić , ].…”