Solar Storms and Power Grids
- A geomagnetic storm is a temporary disturbance in the Earth’s magnetic field caused by charged particles from the Sun. Besides producing auroras, these storms can induce strong, short-lived currents in power grids.
- A new study in Space Weather found that geomagnetic storms can place power grids under unexpected long-duration stress, which may not be fully captured by existing assessment methods.
- The study examined a June 2015 G4 (“severe”) geomagnetic storm that produced an unusual effect in New Zealand, where geomagnetically induced currents persisted for over 90 minutes.
- Researchers from the University of Gothenburg, Sweden, traced the prolonged currents to a possible “mid-latitude ionospheric current wedge”, where part of the ring current in space was diverted into the ionosphere.
- The researchers concluded that current methods for monitoring geomagnetic storms should be updated, as the risk depends on local ground conductivity and the layout of power lines, and protective measures should not focus only on peak current spikes.