Articles | Volume 35, issue 3
Ann. Geophys., 35, 751–761, 2017

Special issue: The Earth’s magnetic field: measurements, data, and applications...

Ann. Geophys., 35, 751–761, 2017

Regular paper 22 Jun 2017

Regular paper | 22 Jun 2017

Modelling geomagnetically induced currents in midlatitude Central Europe using a thin-sheet approach

Rachel L. Bailey1, Thomas S. Halbedl2, Ingrid Schattauer3, Alexander Römer3, Georg Achleitner4, Ciaran D. Beggan5, Viktor Wesztergom6, Ramon Egli1, and Roman Leonhardt1 Rachel L. Bailey et al.
  • 1Zentralanstalt für Meteorologie und Geodynamik, Vienna, Austria
  • 2Institute of Electrical Power Systems, Graz University of Technology, Graz, Austria
  • 3Geologische Bundesanstalt, Vienna, Austria
  • 4Austrian Power Grid AG, Vienna, Austria
  • 5British Geological Survey, Edinburgh, Scotland
  • 6MTA CSFK Geodetic and Geophysical Institute, Sopron, Hungary

Abstract. Geomagnetically induced currents (GICs) in power systems, which can lead to transformer damage over the short and the long term, are a result of space weather events and geomagnetic variations. For a long time, only high-latitude areas were considered to be at risk from these currents, but recent studies show that considerable GICs also appear in midlatitude and equatorial countries. In this paper, we present initial results from a GIC model using a thin-sheet approach with detailed surface and subsurface conductivity models to compute the induced geoelectric field. The results are compared to measurements of direct currents in a transformer neutral and show very good agreement for short-period variations such as geomagnetic storms. Long-period signals such as quiet-day diurnal variations are not represented accurately, and we examine the cause of this misfit. The modelling of GICs from regionally varying geoelectric fields is discussed and shown to be an important factor contributing to overall model accuracy. We demonstrate that the Austrian power grid is susceptible to large GICs in the range of tens of amperes, particularly from strong geomagnetic variations in the east–west direction.

Short summary
This paper describes the study of the effects of solar wind and solar storms on the national electrical power transmission grid in Austria. These storms result in currents in the ground that can cause damage to power grids, particularly those at high latitudes. Results show that very strong solar storms could result in problems in Austria as well, and this information is important to the grid operators to properly implement mitigation strategies in the future.