Grid Impact Evaluation of Localized Geomagnetic Field Enhancements Using Sensitivity Analysis

Geomagnetic disturbances (GMDs) can impose great challenges on power system operations due to geomagnetically induced currents (GICs). During the peak periods of a GMD event, geomagnetic fields may substantially increase in some areas. This phenomenon, known as localized geomagnetic field enhancement, causes the localized augmentation of geoelectric fields and the flow of “extra” GICs. Using the principle of superposition, this paper defines a sensitivity associated with the “extra” GICs to quantify the impact of local enhancements on transformers. Sensitivity analysis is performed on a 20-bus benchmark system and a 10k-bus synthetic network, respectively. The results show that “extra” GICs are localized and suggest that the impact scope of a square local enhancement area is generally less than one and a half times its width.