The Geomagnetically Induced Current Extremal Values Estimation Based on Baygazan Magnetical Station Data

Based on the Baygazan magnetic station data, geomagnetically induced currents (GIC) in the 500 kV Sayano-Shushenskaya HPP (SSHPP) – Novokuznetsk substation power line were simulated during very strong and extreme magnetic storms (planetary geomagnetic index activity ≥ 8) for the period 2012–2024. The 1D Earth's crust conductivity distribution model is used for calculation. It is shown that, the GIC in the transformer neutral can reach 17 A for the SSHPP, and 8 A for the Novokuznetsk substation. The main sources of GIC are rapid high-amplitude bay-like disturbances (up to 17 A) and SSC (up to 5 A). A specificity has been found in the reaction of power line grounding nodes to geomagnetic activity caused by the network topology. A noticeable contribution of various pulsations classes to the GIC generation (up to 5 A) was noted.