$158 million programme of regional upgrades

$158 million programme of regional upgrades submitted to Electricity Commission – 20 Apr 2005

Transpower has sought Electricity Commission approval for a comprehensive programme of regional upgrades to the national electricity grid.

A number of the projects have been completed while others are in the planning stages. Electricity Commission approval will allow Transpower to recover the costs incurred through the Commission’s pricing mechanism.

Transpower Chief Executive Dr Ralph Craven says the regional upgrades submitted for Electricity Commission approval are among those identified in the document Future of the National Grid, published in December 2004.

“We have been communicating the need for these ‘tactical upgrades’ to customers and other stakeholders for the past two years. The most significant projects in terms of cost are those to deliver improved security of supply into Christchurch and the upper South Island.

“In terms of timing, the focus of these 30 projects is to address the short term issues that have already arisen or are likely to arise in the next two or three years. They do not address all the security issues forecast to occur over the next 10 years. In effect, they ‘buy us time’ for the major investments needed in the core electricity grid.

“All of these projects are aimed at extracting the maximum transmission capacity possible from Transpower’s existing assets,” Dr Craven said.

The projects fall within 5 broad categories.

Transmission Line Thermal Upgrades
Using aerial laser surveying technology it has been possible to identify those transmission lines which can be ‘run hotter’, thus increasing their capacity.

Capacitor banks
Capacitor banks installed at Transpower substations improve local voltage quality and reduce voltage instability.

Stringing additional circuits
Two projects in the upper South Island: Islington-Kikiwa and Blenheim-Stoke, involve installing second circuits on tower lines that presently are only fully strung on one side. Easements are required to be purchased as part of these projects.

Installing additional Conductors (Duplexing)
In Canterbury, the capacity of the Livingstone-Islington 220 kV line can be doubled by installing an additional set of conductors in parallel with the existing conductors.

Bussing circuits
The ability to interconnect or “bus” long lines at a convenient mid-point provides a low cost way of reducing the impact of a line outage and increases the voltage stability of the overall system.

“The overall budgeted cost of the 30 projects presented to the Electricity Commission for approval is $158 million,” Dr Craven said. “This is the most significant investment in the national grid for many years.

“We expect the Electricity Commission to consider and approve these important projects under the appropriate provisions of the Electricity Governance Rules.”

ENDS

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