Transpower takes action to protect grid during G4 solar storm

Transpower issued a grid emergency notice this afternoon as it removed some South Island electricity transmission lines from service due to the onset of a severe (G4) geomagnetic storm.  

Removing the circuits from service does not have any impact on consumers’ electricity supply but is an important step to prevent damage to critical equipment should the solar storm get worse. 

Transpower will issue further operational notices either when the storm passes to remove the grid emergency or to provide additional information should the situation change materially or further actions be required. 

 
Background 
Transpower not only monitors weather here in Aotearoa but also 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. When the currents reach transformers in our substations or the large hydroelectric dams, they have the potential to cause extensive damage.  

To minimise the risk of damage to critical equipment, Transpower may work with industry to switch off some parts of the power system for a time in an extreme solar storm. These events are rare, but we are prepared for them and have a plan in place.   

If we don’t do this and equipment is damaged, it could require expensive and time-consuming repairs or the total replacement of equipment. 
  

ENDS  

For more information: please email Transpower’s Communications team at [email protected] or call 021 195 8613.