Voltage Stability Impacts of Geomagnetically Induced Currents

Geomagnetic disturbances (GMDs) have the potential to impact the operation of the high voltage power grid by causing geomagnetically induced currents (GICs) to flow in the transmission lines and transform- ers. These GICs can cause half-cycle saturation in the transformers, resulting in increased transformer reactive power losses. In their 2012 report NERC noted that there are two major risk caused by GICs. The first is the potential for damage to transmission system assets, primarily the high voltage transform- ers. The second is the loss of reactive power support leading to the potential for a voltage collapse. This panel session focuses on the second risk, considering the modeling needed to provide an assessment of GIC related to small and larger disturbance voltage stability.