Аннотация:Influence of the substorm and its fine structure on GIC growth has been considered for the geomagnetic storm 7-8 September 2017. GIC were registered in electric power lines of Kola Peninsula and Karelia by the system of Polar Geophysical Institute and Kola Scientific Center. Geomagnetic field variability was examined using data from the IMAGE magnetometer array. It is shown that during the considered impulsive events the ionospheric currents fluctuate in both the East-West and North-South directions, and they do induce GIC in latitudinally extended electric power line. The both vortex-like currents connected with the field-aligned currents and auroral electrojet have significant contribution into the strong GIC variations. The spatial-temporal distribution of the geomagnetic field variations are does not coincide with the spatial-temporal distribution of its derivation. So the strong GIC is not always associated with the strong geomagnetic disturbance but it associated with fast geomagnetic disturbances embedded
into strong magnetic bay.