One of the inverters is craned into place at Rānui.
The installation of three 14 tonne inverters at Rānui Solar Farm in mid-August marked a significant milestone for the project, with much of the major work now completed.
The inverters which are 6.5 metres long and 2.2 metres wide convert the DC current from the solar panels into AC current which will feed into the Marlborough Lines 33 kV (33,000 volt) network.
Their installation required some planning as the wet winter made the ground muddy and soft.
Several local companies were involved in the installation: Eckford Enginering (frames for the inverters) Hydralift Crane Hire, Harvest Haulage Ltd (trucks and diggers) and MacKenzie Contracting Ltd (gravel spread). Marlborough Lines lifted the 11 kV lines to allow the cranes to operate safely.
The inverters were bolted onto frames on concrete pads, and a crane positioned the inverters within a few millimetres, allowing the 26 bolts (per unit) to be installed immediately.
“We were impressed with how accurately Eckfords had drilled the holes in the frames, with no adjustment required. It’s not uncommon to have to adjust the holes by filing them or redrilling them. Eckfords were ready to adjust the holes if they had to,” says project manager, Wayne Stronach.
Installation of the solar panels was completed by the end of May, and trenches were dug and a trunk cable installed before the wet weather, but about 100 kilometres of cable were installed in wet, muddy conditions.
The next stage of the project will be connecting and testing the DC cables and, installing and testing the 33 kV equipment required to connect to the 33 kV Marlborough Lines network.