Aurora Energy completed a new substation near Lindis Crossing, Cromwell in March 2015. The new substation caters for increased electricity demand in the surrounding area, supplying electricity to homes, farms and businesses. The Lindis Crossing substation is part of Aurora Energy’s overall network development programme with $122 million of investment planned over the next decade in the Central Otago and the Queenstown Lakes region.
Project status: completed March 2015
The Lindis Crossing substation is located on lower Maori Point Road, Cromwell, Central Otago.
What is a substation?
A substation is a part of the electricity supply system that carries electricity from generation sources (such as wind farms and hydro power stations) across the national grid transmission system to the local distribution system then onto consumers. A distribution substation takes high voltage electricity and converts it to a lower voltage. Lindis Crossing substation itakes electricity at 66,000 volts and converts it to 11,000 volts (11kV) for distribution via feeders to local transformers that convert it further to 230 volts for use in the home.
Why was a new substation needed?
Electricity demand in the Tarras, Ardgour Valley and Bendigo areas has increased as irrigation use and the local population has grown. Historically, electricity demand in the area has peaked in winter with home heating. With increased irrigation use, the highest peak is now in summer. The existing Queensberry substation that supplies the area has reached its capacity for reliable supply. The new Lindis Crossing substation on lower Maori Point Road increases the maximum capacity from 2 MVA (megavolt amperes) to 7.5 MVA to accommodate increased electricity demand and peak usage in summer and winter.
Lindis Crossing was chosen because the site is well-positioned in relation to where the electricity is being used and the wider electricity distribution network. The location allowed us to build three high voltage (11kV or 11,000 volt) distribution feeders to improve the reliability of local electricity supply (if there is an outage on one feeder, consumers on the other two feeders will be unaffected). The site is also on the path of the existing 66,000 volt (66 kV) sub-transmission line ring. Importantly, the site is flood-free, flat and easily accessed from the road.
The entire site is about 4,400 square metres. Built structures occupy about 1,500 square metres or around a third of the site and include power transformers, circuit breakers, electrical switchgear and power poles. There is one building, the switch room, approximately 10 by 6.3 metres and no more than 7 metres tall – about the size of a large double garage. The exterior will be finished in natural colours (browns, greens or greys) with screen planting.
We have taken care in the site design to minimise the visual impact. The substation is set back from the road with screen planting around the perimeter fence. The planting is a result of landscape design developed to minimise visual impact.
The tallest structures are six power poles installed inside the substation fence, similar in height to the ones already along Maori Point Road (about 9 metres). The other electrical equipment on site is free-standing and is all approximately 4 metres in height. For safety reasons, we are required to place high voltage electricity equipment at specified heights to meet the industry safety regulations.
Construction started in November 2014 and was completed in March 2015. The construction phases included cabling and overhead line construction, civil works on site (earthworks to level and shape the site, laying concrete pads and foundations), then installation of the electrical equipment, landscaping and planting, testing and commissioning.