Numerical modeling of geomagnetically induced currents in a Brazilian transmission line

Author(s)

Barbosa, Cleiton da Silva ^[1] ; Hartmann, Gelvam Andre ^{[1, 2]} ; Pinheiro, Katia Jasbinschek ^{[1, 3]}

Affiliation

^[1] Observ Nacl, BR-20921400 Rio De Janeiro - Brazil

^[2] Univ Sao Paulo, Dept Geofis, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil

^[3] Nantes Atlantiques Univ, Univ Nantes, UMR CNRS 6112, Lab Planetol & Geodynam, F-44000 Nantes - France

• Document type: Journal article
• Source: Advances in Space Research; v. 55, n. 4, p. 1168-1179, FEB 15 2015.
• Web of Science Citations: 12

Abstract

Rapid changes in the external geomagnetic field induce electric currents in conducting materials at the Earth's surface. These geomagnetically induced currents (GIC) are mostly studied in transmission lines at high-latitude due to their frequent hazards. However, recent studies have shown that low- and middle-latitude regions may also be subject to problems due to GIC occurrences. In this work we apply a numerical model, using plane wave theory and a one-dimensional electrical resistivity model of the region, to calculate the geoelectric field and the GIC measured directly at the Itumbiara-Sao Simao (IS) transmission line (Southeast Brazil) during a magnetic storm occurred between 7-10th November 2004. We use two electrical resistivity models: (a) one-layer model, in which our results do not reproduce the measured GIC directly in the IS transmission. line, and (b) four-layer model, which presents similar patterns of temporal variation and intensities of the measured electric fields and GIC. After validating the four-layer numerical model, we calculate the electric fields and GIC during the ``Halloween storm{''} (29th October-1st November 2003). Our results of the Halloween storm show maximum GIC amplitudes of 25 A, which are higher than registered in other middle latitude countries, such as South Africa and Uruguay. These results indicate that the Brazilian power network might be subjected to the GIC hazards in the future due to strong magnetic storms. In addition, our numerical model might be used as a potential tool for different geological sets, electrical resistivity models, transmission lines with distinct characteristics and for a range of magnetic storms intensities. (C) 2014 COSPAR. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 10/10754-4 - Evolution of the Earth Magnetic Field in South America for the past 500 years
• Grantee: Gelvam André Hartmann
• Support Opportunities: Scholarships in Brazil - Post-Doctoral