Solar Storms Pose Unexpected Slow-Burn Threat to Power Grids, Study Reveals
A new study in 'Space Weather' journal highlights an unexpected "slow-burn" threat to power grids from geomagnetic storms, challenging existing tools for assessment. The research focused on a G4-rated geomagnetic storm in June 2015 that caused geomagnetically induced currents to ramp up over 90 minutes in New Zealand's South Island power grid, rather than intensely spiking. While the currents were only 20 amperes, their prolonged duration can saturate transformer magnetic cores, leading to overheating and wear. The study suggests that a "mid-latitude ionospheric current wedge" caused this diversion, and experts need to update their understanding and protective measures for such unusual, long-duration events.
Key Points
- Geomagnetic storms can pose a "slow-burn" threat to power grids through prolonged, lower-intensity currents, not just intense spikes.
- A June 2015 G4-rated storm in New Zealand caused currents to ramp up over 90 minutes, leading to transformer stress.
- Existing tools and parameters like H' may not accurately capture the effects of these unusual, long-duration events.
- The phenomenon is linked to a "mid-latitude ionospheric current wedge" diverting electric current into the ionosphere.
Exam Facts
- Journal: 'Space Weather'
- Event: G4-rated geomagnetic storm (June 2015)
- Location: New Zealand (South Island power grid)
- Research institution: University of Gothenburg, Sweden
- Agency for space weather prediction: U.S. Space Weather Prediction Centre
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