$100m substation aims to avert power cuts

Transpower chairman Wayne Brown and Prime Minister John Key tour the new substation. Photo / Richard Robinson

Transpower has opened a $100 million substation, which had its construction accelerated following the failure of shackles that cost a few dollars.

The grid operator says the second substation at Otahuhu will help avert power outages such as the one which cut power to 700,000 people in Auckland and Northland in 2006 and cost businesses millions of dollars.

Two corroded D shackles brought two earthwires down on to transmission lines at the existing Otahuhu substation during high winds early on June 12, four years ago.

Transpower chief executive Patrick Strange said the new substation was always on the cards but the power cut was a trigger for its fast-track building.

The 220kV substation, which is separate from the existing Otahuhu substation, is a combination of gas-insulated switchgear (GIS) and an outdoor switchyard.

The substation is part of a series of projects costing $1.7 billion in and around Auckland aimed at diversifying transmission equipment and securing supply.

Major projects include an underground cable circuit between Pakuranga and Albany and the new high-voltage line into Pakuranga from the south.

Strange said within three years, when the Auckland projects were completed, he could sleep easier at night. "We can never guard against the outage in the suburb. We're paranoid about those big collapses but we'll be in much better shape."

The Otahuhu substation was a critical part of Transpower's network - with a third of New Zealand's power supply and nearly all of Auckland and Northland's power supplied through this one site.

"When you have that much going through one physical site it's too much risk. Most transmission companies around the world now have limits on how big a substation can get."

Prime Minister John Key opened the substation yesterday and said the Government had allocated $3.8 billion to capital spending by Transpower whose other projects include rebuilding part of the inter-island link.

Transpower chairman Wayne Brown said the new substation provided insurance in the event of earthwires coming down or even a plane crash into one of the substations.

"We'll have a few issues but the lights will stay on."