Major construction starts on HVDC inter-island link at Benmore substation
18 May 2010
The HVDC Pole 3 project, worth up to $672 million, will increase the capacity of the HVDC link to 1000 MW in 2012 and 1200 MW in 2014. The project consists of building new converter stations at Benmore and Haywards substations, using state of the art thyristor technology to replace the 45-year old Pole 1 equipment.
Transpower’s General Manager Grid Projects Mike Carter said that the Pole 3 project is a major part of a wider investment plan to reinforce the grid.
“The link is critical for enabling renewable generation to supply the North Island and for supporting the South Island demand in dry years,” he said.
“Over the next two years, new converter stations at each end of the link will be constructed and the existing 220 kV switchyards expanded. Although we don’t expect the project to cause much disruption to residents and travellers in the Waitaki Valley, there will be periods when heavy vehicles need to travel to, and from, the substation.
The major pieces of electrical equipment for the project will be installed at Benmore between January and December 2011.Three thyristor valves weighing 17 tonnes each, will be suspended from the ceiling of the 19-metre high valve hall. Six-metre long bushings will transfer electricity between the valves and the outside converter transformers, which weigh up to 330 tonnes each when installed and operating.
Pole 3 will be commissioned in April 2012, followed by the commissioning of a Statcom at Haywards in January 2014 that will lift the capacity of the bi-pole link to 1200 MW.
Pole 1 will be fully decommissioned in late 2011.
Background
The HVDC link transports electricity between the North and South Islands. It consists of two separate circuits with major converter systems at each end. These converter systems are called Pole 1 and Pole 2. They convert electricity from alternating current (AC), which runs through most transmission lines in New Zealand, to direct current (DC) and then back again to AC at the receiving end. DC is used over the HVDC link because it is more effective for transporting power over long distances.
Key facts
- Total estimated cost of $672 million
- Capacity increased to 1000 MW in 2012
- Capacity increased to 1200 MW in 2014
- Total length of HVDC transmission line is 567 km
- Length of HVDC submarine cable is 40km
- HVDC first commissioned (Pole 1) in 1965
- Pole 2 commissioned in 1991
- Weight of new transformers is up to 350 tonnes each
Further information on the project, including photos and updates, is available at www.gridnewzealand.co.nz/hvdc-home.
For further information, please contact:
Rebecca Wilson | Communications Manager | 04 498 2695 | 021 578 608