Power Grid Sensitivity Analysis of Geomagnetically Induced Currents

Geomagnetically induced currents (GICs) have the potential to severely disrupt power grid operations, and hence their impact needs to be assessed through planning studies. This paper presents a methodology for determining the sensitivity of the GICs calculated for individual and/or groups of transformers to the assumed quasi-dc electric fields on the transmission lines that induce the GICs. Example calculations are provided for two small systems and for the North American Eastern Interconnect model. Results indicate that transformer GICs are mostly due to the electric fields on nearby transmission lines, implying localized electric field models may be appropriate for such studies.