Transpower lifts grid emergency after solar storm hits South Island

Transpower issued a grid emergency and took some South Island electricity transmission lines out of service because of a severe geomagnetic storm yesterday. Photo / Michael Craig

Transpower has lifted a grid emergency put in place because of a severe geomagnetic storm that risked damaging South Island transmission lines.

The G4 geomagnetic storm that sparked the move yesterday afternoon was now less severe, Transpower said this morning.

“The South Island electricity transmission lines that were removed from service as a precaution to prevent damage to equipment have now been returned to service.

“There was no impact on consumers’ electricity as a result of the storm.”

Removing transmission lines from service was part of Transpower’s response plan to space weather, developed over several years’ work with Otago University, international space agencies and others in the electricity industry.

“Although New Zealand is well prepared for geomagnetic storms ... it is a timely reminder to Kiwis that they should be prepared for a natural disaster or other major event that could interrupt their power supply and damage other infrastructure.”

What is space weather?

Transpower said it monitors weather in New Zealand and weather in space that can affect our power system.

“Space weather is when the sun ejects plasma and other matter in Earth’s direction. These coronal mass ejections [CME] are rare, and most people won’t notice because our planet’s magnetic field shields us from the particles.

“However, these CMEs can cause geomagnetic storms on Earth and these storms can send unwanted currents through the long electricity circuits that we manage,” Transpower said.

When the currents reach transformers in the Transpower substations or the large hydroelectric dams, they have the potential to cause significant damage.

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