This morning at around 7 all power was turned off to the main substation in Kaitaia, Northland, New Zealand for a period of up to 12 Hours to do emergency maintenance by Transpower.

The incoming line is a single circuit 110 kV line feeding the Transpower substation 4 x 110 / 33 kV transformers, via the Mangamuka ranges.

My brother lives there and checked with me what was going on there, hence I checked with our Auckland controlroom / fault centre who were aware of contractors blowing rocks in the area and somehow may have damaged insulators or pylons.

It's interesting to see that not many customers up north were notified via radio as there are a couple of big timber mills like JNL Timber.

About 10,000 customers were affected, wonder how the charterclaims are going to work out re the contractor who caused the damage.

He needs a please explain and good insurance I guess.

Hi Rodalco, so this was an "Unplanned Shut down" ? Should the public ( and private sector) be warned if theres a likelihood of power-cuts due to contractors screwing up ?

You're absolutely right. Large industrial customers need to know straight away if theres a supply problem.

How would a Timber Mill know if the power goes out, wether its an internal problem or not ? Someone would have to go to the substation and check the protection equipment flags ?

Below are the actual details from that event
Quote:

Quarry blast damages Far North power line - 13 Oct 2006
Blasting at a quarry near Kaitaia this afternoon has damaged a transmission line which supplies Kaitaia and the Far North region.

The incident occurred at the Fairburn Line Quarry, about 10 km east of Kaitaia. Blasted rocks hit wires on the 110 kV transmission line that passes by the quarry.

The power has stayed on but a physical inspection by Transpower’s contractors has determined that the three conductor wires over a distance of about 150 metres have been damaged.

The transmission line is the only electricity supply into the Far North and will have to be removed from service to allow the damaged wires to be replaced. Preparations will be made at the site tonight and tomorrow, with the work likely to occur on Sunday.

Removing the line from service will cut the supply of electricity to the Kaitaia substation. An outage of up to 8 hours may be needed on Sunday in order to complete the work. The details will be worked out with the local lines company, Top Energy.

Top Energy has advised that this will affect all areas north of the Mangamuka Ranges, all of North Hokianga, except Kohukohu township, and all areas north of and including Taupo Bay.

The Police and other emergency services, Kaitaia Hospital, the Juken New Zealand Triboard Mill, Vodafone and Telecom have all been kept informed of the situation.

Details of the planned outage on Sunday will be confirmed tomorrow.

END.

Regards

Raymond

So the blasted rocks hit an overhead line ?

Is the "explosive expert" liable ?

Kiwi,

As the holder of an explosives licence myself, I would say quite possibly.
Sounds like someone mis-calculated the charge required for the blast.