Transpower plans to install spikes on its towers near the Topuni River in Northland in a bid to stop birds perching there in hopes of preventing further power outages.
File image. Photo: RNZ / Russell Palmer
The national grid operator is blaming bird droppings for tripping a high-voltage circuit breaker that caused a major power cut on Wednesday morning.
About 90,000 properties in the Northland region were without power for three hours.
Transpower chief executive Alison Andrew said an inspection of the site found excrement from large birds was the most likely problem.
"What happens is when birds, particularly large birds, such as the size of herons, take off ... their excrement can span across a couple of phases and short out the power supply ... even it might be something it's carrying is large enough to span across a couple of phases, it can short out the electricity," Ms Andrew said.
"What we will be doing is making sure we have got good bird deterrents on the tower. We will try to make the towers as uninhabitable for birds as possible. We're also looking at other innovations, ways we can actually deter the birds from our towers.
"In some instances we have auto-reclose on our systems which would have cleared the fault and normally when we'd have this instance you'd have the other circuit available so we would have kept supply to Northland.
"So this was a circumstance that was unique with one circuit down for maintenance and the second circuit has tripped (and) we had (the auto-reclose) disabled for safety reasons, safety of equipment and people."
She said bird deterrents would be installed on the towers in the next few days.