Event Details

Our modern society depends as never before on a reliable electric grid, and usually it works as expected. However, there is the potential for what the North America Electric Reliability Corporation (NERC) calls High-Impact, Low-Frequency (HILF) events to plunge us into darkness. This presentation covers one such HILF risk, geomagnetic disturbances (GMDs). GMDs, which are caused by corona mass ejections (CMEs) from the sun, have the potential to affect the power grid. This is due to the CMEs impacting the earth’s magnetic field, which in turn can induce quasi-dc electric fields in the earth (with frequencies usually much below 1 Hz). These electric fields then cause geomagnetically induced currents to flow in the high voltage grid that can cause halfcycle saturation in the power transformers, resulting in increased transformer reactive power losses resulting in widespread blackouts and, perhaps, transformer damage. This presentation provides an overview of the impact of GMDs on the grid, shows how this impact can be modeled and visualized, and discusses mitigation strategies.