Transpower will increase the south to north transfer capacity of Pole 2 from 500 MW to 700 MW next month by reconfiguring the three operational undersea cables of the inter-island high voltage link (HVDC).
In order to increase the capacity of Pole 2, one of the two undersea cables currently connected to the ‘stood down’ Pole 1, will be transferred to the operational Pole 2 on 13 -17 December 2007. Transpower’s General Manager National Grid David Laurie said that this step is being taken to maximize the capacity of the HVDC link while an evaluation is underway to assess whether to re-instate Pole 1 or decommission it.
“The three cables currently have the potential capacity of just over 1000 MW. Following the ‘stand down’ of Pole 1, this was reduced to 500 MW. It was decided that one of the cables from Pole 1 should be transferred to Pole 2, which would increase the link to 700 MW, leaving only a 300 MW shortfall from the original configuration.
“Increasing the capacity of Pole 2 at this time is purely a precautionary measure to ensure that there is maximum capacity should there be a need for significant northwards power transfer over the summer period.”
“In the event that there is a lot of rain over the summer period, particularly over Christmas and New Year, this arrangement will ensure that maximum use can be made of South Island water in generating power for the benefit of all of New Zealand.“
“The work to transfer the cable has been carefully planned and the necessary equipment is all in place. The System Operator has been notified of the change and is making the necessary changes to market dispatch systems to accommodate the increase in Pole 2 transfer capability.”
Transpower has commissioned an evaluation of what mitigation measures could be undertaken in order to return Pole 1 to service, and the associated costs. “Once the evaluation has been finalized, consideration will be given to the recommendations and associated costs to return Pole 1 to service, “Mr Laurie said.