We are focused on proactively investing in critical network infrastructure, to ensure we can provide a reliable and resilient supply that can meet the growing demands of our connected consumers in Whangārei and Kaipara.

The Kensington substation is the largest in our electricity distribution network, supplying power to more than 28,500 homes and businesses in the growing Whangārei district.

Significant upgrades to this substation are underway in anticipation of meeting future increased demand, ensuring we can continue to provide a reliable power supply that serves the energy needs of our growing communities.

Construction of the switchroom, and installation of transformers and switchgear will be done in stages. Equipment will be commissioned and livened at the completion of each of the construction stage to minimise the potential power outages for customers.

The first transformer was livened and the realignment of the last span of the high voltage conductors from Maungatapere was all done on de-energised equipment, but without any power outages to our customers. 

Significant civil work on the substation site was required to create room for the temporary pads and the additional switchroom building. With the help of local civil contractor, Steve Bowling Contracting, vegetation and embedded rock were removed from the site in late 2024. 

Towards the end of 2024 and into the start of 2025, earthworks began, the foundations for the switchroom were prepared in anticipation of precast panel installation, retaining walls were constructed and backfilled, 750 tonnes of contaminated soil was removed to a Redvale managed dump site, we excavated then poured the concrete for the new transformer foundation pad. 

In a great example of sustainable thinking, the excavated rock was cleaned and repurposed to form the new southern embankment, finished with a Terralink mattress for a strong, stable, and visually tidy edge. 

Timelapse of Kensington substation site preparation

In June 2025, construction of the transformer pads was completed with the first of the 100MVA transformers moved into place. The switchroom building construction phase was also completed before starting the internal fit out of the 33kV equipment. 

As part of the project, we are securing the main lines that get the power from the grid exit point at Maungatapere to Kensington, but land access to a tower that needed stabilising became an issue for our heavy overland machinery. The decision was made to fly in the equipment required by helicopter to the tower in the Western Hills, and use modern anchor technology to stabilise it, as opposed to concrete blocks. 

In October 2025, the second transformer was moved into its new position, and outdoor 110kV switching equipment and the indoor 33kV equipment were ready to go. The job of commissioning and livening this new equipment spanned five meticulously planned days. Our Transmission team stood the remaining section of the new gantry, removed the three phases of high voltage conductor from the old structure, and reconnected them to the new gantry. Each conductor, weighing close to 1,000kg per line, was carefully handled, tested, and verified.  

The commissioning team worked late into the night, running exhaustive tests and troubleshooting to ensure all targets were met, and that the new transformer could be safely and reliably energised on schedule. 

By the end of day three, it purred into life, with everything performing exactly as designed. The new switchroom is now live, running the newly commissioned portion of the switchyard, strengthening the network and laying the groundwork for the next phase of the project. 

Timelapse of the installation of the first new transformer

Read more from the Annual Report 2025