Continental scale modelling of geomagnetically induced currents

¹ Finnish Meteorological Institute, Helsinki, Finland
² Natural Resources Canada, Ottawa, Canada
³ NeuroSpace, Malmö, Sweden
⁴ Research Centre for Astronomy and Earth Sciences of the Hungarian Academy of Sciences, Sopron, Hungary
⁵ Polar Geophysical Institute, Apatity, Russia

^* corresponding author: e-mail: ari.viljanen@fmi.fi

Received: 23 May 2012
Accepted: 17 September 2012

Abstract

The EURISGIC project (European Risk from Geomagnetically Induced Currents) aims at deriving statistics of geomagnetically induced currents (GIC) in the European high-voltage power grids. Such a continent-wide system of more than 1500 substations and transmission lines requires updates of the previous modelling, which has dealt with national grids in fairly small geographic areas. We present here how GIC modelling can be conveniently performed on a spherical surface with minor changes in the previous technique. We derive the exact formulation to calculate geovoltages on the surface of a sphere and show its practical approximation in a fast vectorised form. Using the model of the old Finnish power grid and a much larger prototype model of European high-voltage power grids, we validate the new technique by comparing it to the old one. We also compare model results to measured data in the following cases: geoelectric field at the Nagycenk observatory, Hungary; GIC at a Russian transformer; GIC along the Finnish natural gas pipeline. In all cases, the new method works reasonably well.