Impact of 1D vs 3D Earth Conductivity Based Electric Fields on Geomagnetically Induced Currents

Electric fields that drive geomagnetically induced currents (GICs) depend on the deep earth conductivity. In a power system GIC study, the model used to represent this conductivity thus influences the GIC results. In this paper, we evaluate the differences between the commonly used lD conductivity model and the more complex 3D transfer functions, in terms of their impact on simulated GICs, by validating them against actual GIC measurements. The goal is to provide illustrative results on the performance of these models, in order to show the present capabilities and areas for improvement of conductivity models, and power system GIC modeling. The paper highlights the importance of data availability for model validation research, in order to mitigate the GMD risk.