Powerco and Tenix lineworkers battled a “once in a lifetime” arctic storm in New Zealand to keep power on to approximately 420,000 consumers across the upper central and lower central North Island.
A polar blast of snow, sleet and gales blocked roads, grounded flights, closed schools and cut power across much of New Zealand earlier this year.
The country’s largest city, Auckland, witnessed its first snowflakes since the 1930s while Wellington was covered to an extent not seen since the 1970s. Fifteen to 17 cm of snow covered most of the lower North Island.
State Highway One, the main road link between the capital Wellington and Auckland, was severed when snow blanketed the Mt Ruapehu volcanic plateau in the centre of the North Island.
The intensely cold weather was due to a large high pressure system stretching more than 6000 km from the tropics to Antarctica merging with three neighbouring low-pressure systems.
Tenix employees were quickly assembled to manage the impact of the snowstorm and support the electricity network owner Powerco, to many of its 420,000 North Island consumers.
Staff and contractors excelled in responding to faults caused by the winter storm, having to manage 163 high-voltage faults, or roughly a month’s work in six days, and all without any major injuries.
“We had 84 employees, 14 subcontractors and 32 vegetation contractors helping with the work, some into the night,” Tenix executive general manager Jacob Bonisch said.
“Wanganui and Taranaki were the areas with the most damage, although Wairarapa, Manawatu, Wanganui all had damage to some degree,” he said.
Most of the damage was caused by trees breaking under the weight of snow and falling onto wires or trees falling straight through lines breaking poles and wires. Helicopters were also used to re-erect lines and more than 300 trees were cleared.
In Tauranga and Palmerston North the mercury fell well into negatives degrees celsius, the lowest since the 1940s, ensuring that power supplies needed to be fixed fast and efficiently. This was the priority for the Tenix crews.
In one location a helicopter was used to circulate air and to remove the snow loading, eventually restoring supply to the Tasman, Ngariki and Pungarehu substations, affecting more than 3000 consumers. The outage caused the shutdown of the Maui gas supply, creating a gas shortage emergency during peak times.
Calling in support from neighbouring areas while dealing with multiple calls was a logistics challenge. Access in most areas was via helicopters only and any road access was laden with black ice, creating dangerous conditions for the crews.
Supply was also lost to Taupo Quay, Beach Rd and Blink Bonnie substations following bird contact with 11kV lines immediately opposite the Blink Bonnie Substation, tripping the supply circuit breaker, further adding to the workload.
“We are proud of the whole team who have rallied together to deliver such outstanding performance in what is a rare weather event for New Zealand. It’s great to know that we can pull together to face these challenges head on” Mr Bonisch said.
Powerco network operations manager Phil Marsh said Powerco and Tenix worked safely and effectively in trying conditions to restore supply to customers quickly.
“When it’s freezing outside and you have no power, life can be pretty bleak. Tenix field staff demonstrated their commitment to our customers by working through the cold and snow to get power back on to customers in a safe and efficient manner and they are a credit to the profession,” Mr Marsh said.
“Feedback from our customers about the good work of our field services contractors reflects well on our industry and the crews can be proud of their efforts.”
While being described as a once-in-a- lifetime storm, the country may have to learn to deal with more frequent intense storms in the future.