Influence of a Geomagnetic Storm on the ELF Field of Power Lines

It has been suggested that extremely low frequency (ELF) emissions can serve as an indirect remote means of detecting overloads in the operation of energy networks caused by geomagnetically induced currents (GICs). An analysis of the data from the recording system for GIC in power line transformers, a magnetometer, and an ELF receiver on the Kola Peninsula during a magnetic storm on September 7–8, 2017, showed that the intensity of radiation at an industrial frequency of 50 Hz and its third harmonic of 150 Hz increases with increasing GIC. Apparently, under the influence of GIC, the transmitted currents in power transmission lines (PTLs) are unbalanced, so that the PTL becomes a large-scale antenna and radiates both at the fundamental frequency of alternating current (50 Hz) and its harmonics. The discovered effect of the increasing imbalance of currents in PTLs has not previously been noted as a possible factor in the impact of space weather on energy systems.