Northpower’s Kensington substation, and the lines that feed it, supply a critical link between Transpower’s national grid, and the distribution network that feeds Whangarei city and the surrounding suburbs.
An inspection of these assets completed towards the end of winter 2022 found a major area of land subsidence near one of the large lattice towers that supports these lines. At the time, specialist inspection and monitoring of the subsidence by Northpower’s geotechnical consultants confirmed that the foundations of the tower were likely to be undermined, so work started to build a temporary solution to bypass the impacted area and ensure power supply would be uninterrupted in the event of further land movement.
Northpower’s construction teams have been working tirelessly over the last six months to engineer a solution that would remove dependency on the impacted tower. These works, which involved construction of two temporary 110kV bypass lines around the impacted tower, are now complete.
Initially one bypass line was completed before Christmas, leaving the supply to Kensington substation reliant on just one line. Earlier in April, construction of the second bypass was completed, despite the challenging terrain and ongoing wet weather we have seen over summer.
The two bypass lines are designed to last for several years, while a more permanent solution is engineered, to minimise the risk from any potential future landslips.
Northpower would like to thank Whangarei District Council, Northland Civil Defence and our customers impacted by the work for their continued support as we work to resolve this issue. If there are any concerns people are welcome to contact our customer centre on 0800 667 847.