National Grid Today
North Island
The main transmission grid in the North Island comprises of 220 kV and 110 kV lines connecting major demand centres with generating stations. North Island generation is spread throughout the island and is based on a number of generation technologies: hydro, conventional thermal, combined cycle gas, co-generation and geothermal.
Most of the generation plants are located some distance from the major demand centre in the Auckland region. The North Island is also supplied by the high-voltage direct current (HVDC) line that runs from Benmore substation in the South Island to Haywards substation near Wellington.
South Island
The transmission grid in the South Island consists of 220 kV, 110 kV and 66 kV lines. All major generation in the South Island is from hydro stations, with most generation sources in the Waitaki and Clutha Valleys.
The National Grid is made up of the following assets:
| Asset Description | Detail |
|---|---|
| Length of HVAC and HVDC Transmission Line | 11806 km |
| HVAC Transmission Line Voltages | 220, 110, 66, 50 kV |
| HVDC Transmission Line Voltages | 350, 270 kV |
| HVDC Link Capacity (with two cables on pole 1) | 700 MW* |
| Substations | 178 |
| Capacitor Banks | 124 |
| Transformers (Units) | 1116 |
| Transformers (Banks – excluding HVDC) | 343 |
| Synchronous Condensers | 10 |
| Static Var Compensators (SVC) | 4 |
| *Pole 1 was stood down from operation in September 2007. One half of this Pole will be made available for limited use to supply peak load periods. Approximately 270 MW additional will be made available by this action. | |
