Kensington substation upgrade
Location: Kensington, Whangārei
Investment: $10.6 million
Start Date: October 2024
Key people involved: Grant Lovie
Project partners: Elsewedy Electric, MOVE Logistics, Haye Metals, Steve Bowling Contracting, ESI Group
Upgrading assets for a growing population
The Kensington substation is the biggest in Northpower’s electricity distribution network, supplying power to 28,500 homes and businesses in the Whangārei district. A substantial upgrade is underway, ensuring continued reliable power supply to our growing population.
Upgrades will also include construction of an additional switchroom building, upgrading end-of-life switchyard equipment, including the high voltage circuit breakers and protection equipment.
This upgrade will not only improve efficiency but also help safeguard Northpower’s network against future challenges, ensuring homes and businesses continue to receive a stable and uninterrupted energy supply.
Oversized transport to site
The main part of the substation upgrade is replacing the existing transformers that have reached the end of their lifespan. Northpower’s Network team have taken the opportunity to improve upon the current network, by sourcing two purpose-built 110/33kV three phase 100MVA transformers from Elsewedy Electric in Indonesia. These purpose-built transformers are designed to operate more quietly in the residential area while doubling the substation’s capacity and provide improved security of supply.
Months of planning was involved in getting these huge specialised transformers to site. On arrival at the Northland Port in October 2024, the transformers were loaded onto an oversized transport truck by a shipping crane. After a two-hour journey to site, the transformers were moved by a series of constructed gantries onto a temporary pad, for partial assembly while new foundations are being built.
Preparing the site
Civil work to remove vegetation and dig out embedded rock from the site is the next part of this project, with the help of Steve Bowling Contracting. 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 approximately five weeks ahead of the schedule.
Working together and minimising the impact
Different divisions of Northpower are involved in the project, including our Network,Transmission, Contracting and Electrical Services teams, along with several other external contractors.
Civil works have been consented by Whangārei District Council and are undertaken during regular working hours. This includes the digging and levelling the site, trenching and hydro extraction, and rock breaking, which were all done with noise-mitigation measures in place.
Construction of the switchroom, and installation of transformers and switchgear will be done in stages. Equipment will be commissioned and livened at each stage completion with minimal, if any power outages to customers
The project is expected to be completed in December 2026.
Full scope of works
Replacement 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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Kensington substation upgrade
