Kensington substation upgrade
Location: Kensington, Whangārei
Investment: $22.4 million
Start Date: October 2024
Project partners: Elsewedy Electric, MOVE Logistics, Haye Metals, Steve Bowling Contracting, ESI Group
Investing in critical infrastructure locally
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.
$22.4m
total project investment
2
three-phase transformers to be installed
750
tonnes of soil moved for expansion
1265
person-hours invested
Upgrading assets to support growth
Upgrades include the construction of an additional switchroom building, upgrading end-of-life switchyard equipment, the 110kV power transformers, and circuit breakers, and reconfiguring the switchyard to improve reliability.
We have invested $9.4 million on upgrading the substation this year. The total investment for this project is $22.4 million. It is expected to be completed by December 2026.
Preparing the site
Civil work to remove vegetation and dig out embedded rock from the site has been completed, with the help of local civil contractor, Steve Bowling Contracting to create room for the temporary pads and the additional switchroom building.
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 have been constructed and backfilled, 750 tonnes of contaminated soil has been removed to a Redvale managed dump site, excavation for the new transformer foundation pad is complete, and the site concrete has been poured – marking a significant milestone, ahead of the schedule.
Timelapse of Kensington substation site preparation
Oversized transport to site
The main part of the substation upgrade is replacing the existing transformers that have reached the end of their life. Northpower’s Network team sourced two 110/33kV three phase 100MVA transformers from Elsewedy Electric in Indonesia. These will double the capacity of the substation while providing improved security of supply.
Months of planning was involved in getting these two new 92–tonne, specialised transformers to site. On arrival at the Northland Port, the transformers were loaded onto an oversized transport truck by a shipping crane. After a two-hour journey to site, the transformers were moved using a series of specially constructed gantries onto a temporary pad, allowing for partial assembly of the transformer while the new foundations are being built.
Moving things into place
Contruction of the first transformer pad was completed in June 2025 with the first of the two 100MVA transformers moved into place. The switchroom roof has been installed, completing the construction phase, with the internal fit out getting underway. The installation of the 110kV outdoor equipment is also well underway.
As part of the project, we are securing the main transmission lines that deliver 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.
Working together and minimising the impact
The size and scale of this project has drawn on the specialist skills from a number of Northpower teams, including our Network, Transmission, Energy Services and Electrical Services teams, supported by several external contractors.
Civil works were consented by Whangārei District Council and were undertaken during regular working hours. This included the digging and levelling of the site, trenching and hydro extraction, and rock breaking, which were all done with noise-mitigation measures in place.
Kensington substation upgrade progress in June 2025
Minimising power outages
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.
Increasing the resiliency of our network
This extensive project is the biggest singular upgrade to our network in decades, shows our commitment to increasing the resiliency of our network, and the reliability of supply, for our local communities.
Full scope of works:
- Replacement and reconfiguration of 110kV outdoor switchyard, including new circuit breakers and associated equipment.
- Replacement of six 110/33kV single phase transformers (designated as T1 and T2) with two new 110/33kV three phase 100MVA transformers.
- Construction of a new 33kV switchroom building to house a replacement 33kV switchboard.
- Upgrading of all 110kV and 33kV protection at the substation.
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