Transpower and Unison invest in infrastructure to meet consumers’ future energy needs

27 April 2021

High voltage transmission network owner and operator, Transpower New Zealand, and Hawke’s Bay electricity distributor, Unison Networks, are investing $20 million into the Fernhill substation to ensure it can meet consumers’ future energy needs.

Providing power to the southern Hawke’s Bay region for over 93 years, the Fernhill substation supplies around 15,000 consumers in Havelock North and Hastings, including major industrial/commercial customers Alto Plastics, McCains food factory and the Hawke’s Bay Hospital. It also acts as a conduit for moving power around the region during outages, from Redclyffe through to the generation scheme at Tuai.

The upgrade encompasses two main projects to prepare the facility for future growth in load and distributed energy resources including renewable generation. The first project was completed at the end of last year with the conversion of an outdoor 33,000 Volt switchyard – used to supply Unison’s zone substations Flaxmere, Camberley, Irongate, and Havelock North – into an indoor facility.
Transpower Project Manager, Brian Carwell-Cooke says older outdoor switchyards of this voltage can prove challenging for network operators.

“The standards around electrical distancing for people and plant were only in their infancy when this substation was built. So, it’s always been a bit of a squeeze for our crews and difficult to maintain.

“We had to turn more of the switchyard off just to safely access and maintain equipment, and being outside, nesting birds caused maintenance issues. By bringing it indoors and replacing mechanics with electronics, the risk to crews has been eliminated, while also reducing maintenance costs,” says Mr Carwell-Cooke.

The new smart electronics installed also provide Unison with greater visibility and data behind any faults on their network from the Fernhill supply.

Unison General Manager Network and Operations, Jaun Park says this means quicker identification of fault type and location, resulting in faster restoration to consumers.

“The upgrade of Fernhill, together with other investments planned in the next 18 months, will make it easier for us to divert power to keep critical customers – such as the hospital – powered during any outage,” says Mr Park.

The second major project will see the smaller of the Fernhill substation’s two transformers replaced with a much larger unit, future proofing capacity for the next 20 years.

Mr Park says a decision made now has to last well into the future given a well-maintained transformer can last decades – the existing transformers are 50-60 years old.

“We initially considered a transformer of the same capacity as the original transformer. However, the marginal costs for greater capacities are insignificant, and we are mindful that electrification of industrial processes, and transport is expected within its lifetime, so we are planning to invest in a larger unit”.

While the substation won’t look much different once all work is completed (around mid-2022), if well-maintained, it will continue to service the community for many more decades.

Pictured (L-R): Unison General Manager Network and Operations, Jaun Park, and Transpower Project Manager, Brian Carwell-Cooke, at the Fernhill substation in Hawke’s Bay.