Modelling Geomagnetically Induced Currents in the German Transmission Grid for 2023 Geomagnetic Storms

Geomagnetically Induced Currents (GICs) are a form of low-frequency parasitic current resulting from geomagnetic dis-turbances that pose a risk to grounded power systems. Changes in the Earth's magnetic field induce an electric field that drives the GICs. Due to their particularly low-frequencies, GICs are considered quasi-DC in relation to the power grid frequency, so they can lead to half-cycle saturation of transformers and have the potential to damage the grid. The hazard GICs may pose to the German power grid is still unknown. This study serves as a first step towards quantifying the GIC risk in Germany by providing new modelling results for GICs generated by geomagnetic storms that occurred in 2023, together with DC measurements at transformer neutral points during the same period.