Kaikohe substation equipment failure – 6 November

What happened

• Around 5.20pm, an equipment failure inside the Kaikohe substation caused a major outage affecting about 23,000 customers.
• A protection breaker catastrophically failed, which triggered the fire suppression system and damaged part of the 33kV switchboard.
• The failure caused significant arcing and heat but no fire and no widespread physical damage, but:
  
  • Half of the 33kV switchboard is out of service.
  • We are currently running on our smallest transformer at Kaikohe.
  • Ngāwhā generation is offline for planned annual maintenance, so we don’t have our usual backup
  • We’re using diesel generation at Omanaia to help support the southern part of the network.

Key point:

This was an internal equipment failure at the substation.

What we’re doing now

• Assessing the damaged switchboard and planning repairs and replacements.
• Reviewing the equipment failure to understand exactly what went wrong and how to reduce the chance of it happening again.
• Working to restore full backup and security of supply as quickly and safely as possible.
• At this stage we do not know how long it will take to replace the damaged equipment and reinstate full backup.

How you can help

While capacity is reduced – which may be for a week while equipment is repaired:

• Use power wisely – especially during morning and evening peaks.
• Avoid unnecessary heavy use (e.g. multiple large appliances at once).
• Turn appliances off at the wall if you don’t need them.
• You can see more tips at: www.topenergy.co.nz/tell-me-about/power-and-saving

If you or someone you support is medically dependent on electricity:

• Please make sure your back-up plan is ready.
• If health or safety is at risk, call 111 immediately.

Mount Pokaka 33kV line – 31 October

What happened

• Around 4pm, a tree fell onto the 33kV line to Mount Pokaka, cutting supply to around 23,000 customers.
• The primary protection for the line didn’t operate as expected, so the backup protection tripped the rest of the substation, causing a wider outage on all of the lines.
• Crews removed the tree, inspected the line, and restored power.

Key point:

This was a weather/vegetation incident on the line, not a substation equipment problem.

Talk with us

We’re here at the Bay of Islands P&I Show on Saturday 8 November to answer your questions and listen to your feedback.

Thank you for your patience and understanding while we work through these issues and restore full security of your power supply.