Observations of Geomagnetic Induced Currents in Northwestern Russia: Case Studies

This paper analyzes a number of events of recorded intense geomagnetically induced currents (GICs) in transformers at stations located on the Karelia–Kola power transmission line in northwestern Russia and in a magnetometer at a gas pipeline compressor station located near the city of Mäntsälä in Finland. Located in the auroral and subauroral zones, these two different GIC recording systems made it possible to trace the occurrence and dynamics of GICs from subauroral to high latitudes and compare them with the motion of the substorm westward electrojet according to data obtained by the Scandinavian network of IMAGE magnetometers. For a detailed study, two events were considered (March 15, 2012 and March 17, 2013), when intense GICs were observed in the technological networks under consideration. It is shown that the development of GICs on the meridional observation profile is consistent with the latitudinal motion of the westward electrojet and corresponded to the appearance of successive substorm intensifications. In addition, a relationship has been established between the appearance of GICs and an increase in the intensity and wave activity of a substorm, determined from the IL and Wp geomagnetic indices.