Evaluating Static and Dynamic Impacts of Geomagnetic Disturbances on Interconnected Power Grids

Abstract

Geomagnetic disturbances (GMDs) can potentially impose operational challenges on power systems and cause damage to essential grid assets through geomagnetically induced currents (GICs). Therefore, to maintain power system efficiency and reliability, it is essential to study how GMDs impact power systems. This work contains two separate research topics related to GMDs. The first research topic is associated with a spatially non-uniform GMD event called localized geomagnetic field enhancement. Characterized by geomagnetic fields substantially increasing in some areas, localized geomagnetic field enhancements cause the localized augmentation of geoelectric fields and flow of “extra” GICs in power grids. Considering that the distribution of the “extra” GICs directly affects the planning and operations of the grids, this work utilizes the superposition principle and defines a sensitivity associated with the “extra” GICs to study the impact scopes of localized geomagnetic field enhancements. Sensitivity analysis is performed on a small 20-bus benchmark system and a large 10k-bus synthetic network, respectively. The results show that the impact scope of a square localized geomagnetic field enhancement area is generally less than one and a half times its width. In other words, the “extra” GICs are localized. The second research topic focuses on studying the impacts of GMDs/GICs on power system transient stability under different contingent conditions. In the work, various contingencies are applied to the 10k-bus synthetic network individually in the presence of time-invariant GMDs, while the changes in the transient stability margin are evaluated using different metrics. Several case studies are presented as examples of the potential effects of GMDs. The results show that GMDs can alter power system transient margin. Therefore, this work suggests that relevant transient stability studies may need to be conducted to ensure secure power system operations under the effect of GMDs.