It happened again, power was out in a large part of Auckland and up North towards Whangarei and Cape Reinga.

A 220 kV line going North was tripped in Onehunga while a large shipping container was within the safe M.A.D. of one of the main 220 kV lines.
A flashover occured to the container stacker.
The driver was ok but shaken.

The other main 220 kV circuit going North was out for maintanance, the trip of the other line caused a domino effect and power went off for about 1 hour.

It is being addressed that the system in Auckland needs a back up double circuit line going north which will take an other 5 years to be in place.

My question is why have a shipping container stacking yard within the easement of overhead 220 kV lines ?

http://tvnz.co.nz/national-news/major-power-cut-hits-auckland-northland-3101635

Just a new topic to get some conversation going.

Kind regards, Raymond

Woah!,
Our lights seemed a lot brighter down here in the South Island today.
We even shut 3 generation stations down and had Benmore idling.

Could this be because all the Latte machines in Auckland had no power?

Even so Ray, I think it really comes down to the people that voted and protested against the 400kV upgrade.
If that had have gone ahead, the lines would have been a lot higher.

You reap what you sow.

Overloaded Auckland lines sag a lot and the clearances are less, hence the container stacker got away with it under normal conditions but not while one circuit was out.

The 400 kV line may be built now a bit faster although this incident happened between Otahuhu and Henderson, and this power black out would also have happened if the 400 kV line was in place.

Aucklanders and myself love our latté and capuchinno and our coffee machines were off indeed :-)

Lucky that the South Island generation didn't trip off on overfrequency because of the sudden load loss on the network.
Those hard working S.I. generators probably appreciate a little break in their arduous duties for the power hungry Auckland city dwellers.

I wonder if any HV powerlines or the DC lines were swaying because of the instant drop of a large load.

Ray,
I hope you realise that most of what I posted above was in sarcasm.

Personally,
I hope that most of the affected loads have now been re-energised, although with my experience of re-connections, that would not have been an easy task.

No worries mate, I knew that coffee :-) :-) stir, but it is great for a chat and laugh.

The re-energising took a couple of hours as loads were switched on in sequence to avoid further problems.

I was working at Penrose switchyard which was not affected and is fed from another double circuit 220 kV line.
Installing a 250 MVA interconnector transformer 220/110kV to secure the CBD supply. I will post some piccies and will start a new thread about that job.

Ray, does your utility do a nip and tuck on existing transmission lines to improve clearences?

The utility that services my part of Canada is doing that on up 20 to 90 year old HV transmission lines to improve clearences brought on by the extra loads that were not there when the lines were built.

Apparently if they do it correctly they can increase transmission voltages by 100% and still have proper ground clearence.

They do.

On the 220 kV lines around Auckland they have replaced the hanging insulators on certain pole structures.
Instead of the hanging strings there is a triangular arrangement with resin insulators and increased the clearances from the conductors by several meters.

I will take a photo in my travels and post it in the photo gallery.

This issue is still under investigation but it appears that this container firm has had a line clearance warning before but that didn't cause an incident.

What is a M.A.D ?

Minimum Approach Distance??

Always good when the power goes out for a while.
Give us a chance to get the really important things done that don't need power.

OA

Oddly enough Ray,
It's not just Auckland that gets hit with power outages:

From today's Timaru Herald on-line:

Major power outage hits Timaru:

Power has been restored to Timaru and surrounding areas after a fire at a substation caused a major power blackout to around 20,000 homes this morning.

The power cut affected an area from the Opihi River to the city's east, as far northwest as Cave and Cannington, including Pleasant Point, and as far south as Otaio, including Pareora and St Andrews.

Alpine energy said all affected customers should now have power again. If anyone is still without power, they are asked to cal (03) 687 4300 or 0800 661 177.

A statement from the company said it "apologised for any inconvenience" caused by the outage and added some hot water cylinders may still be without power.

"As electricity has been turned off for some time today, hot water will not be immediately available. We will be restoring hot water power gradually throughout the night."

It is understood the fire, at the Timaru substation on the Old North Road, started at around 5.15am.

There was a cable fault in the Transpower switch room which led to a small explosion.

Firefighters were at the scene just after 7am and the fire has since been put out.

A spokesperson for Timaru Hospital said the hospital had also been affected by the outage and had a generator running.

Some schools and kindergartens in the area had closed.

Traffic lights had also been knocked out throughout the area, with police directing traffic at intersections.

Alpine Energy is still asking people to reduce the amount of power they use.

Link: Article at Timaru Herald

It was on the Tuesday 0700hrs morning radio news, and I was aware of it.
The media was talking about an 11kV fault but to affect so many customers it would be more likely a 33 or 66kV fault ??

Did it affect Ashburton at all ?!

What's all this about restoring hot water power. Is there a separate feed just for hot water cylinders in NZ? Is it at a different rate?

Gidday Ray,
No it didn't affect AshVegas, but I've been wiring a dairy shed down on the other side of Timaru, I was wasn't aware of what had happened until I turned up at work down there and the farmer told me what had happened.

I was talking to a guy that works for NetCon down there and he said it was the secondary side of a 66/33kV tranny that all of a sudden decided to go belly up.


It isn't a totally seperate feed for the hot water, but for it to work, the controls have to be energised.
Having an electricity supply to run the element also helps too.

New Zealand uses what is known as Ripple Control, where control tones are sent down the mains wires to activate and de-activate a relay in the customers meter box.

These control tones are around 1100-1200Hz and are traditionally sent out at 2300Hrs (energisation) and 0700 (de-energisation).

This system is called the Night-Rate supply and is (slightly) cheaper than the day rate electricity.

It also requires a second meter in your meter box.

Here is a pic of the meter box from the house I used to live in a while back:



The meter on the left is the General Supply meter, in the middle is the Ripple Relay and on the right is the Night Rate meter.

OK, makes sense. We poms have a system called economy 7, seven hours overnight at cheaper rate though the control generally is by a meter driven off the 50 Hz supply.

Thanks Mike for that update, the 66/33 kV makes more sense than the media woffling on about an 11kV fault.

Winston_1

In NZ we also have a pilot system which drives a relay in the meterbox which is energised all the time and switched off during high demand periods on the network.
It requires an extra control wire to the meter panel to operate that relay.
There is also an extra control wire on the poles or pillars in the street.

The UK tariff usually has one meter with two registers on the dial.
The top dial is often the night (low tariff) rate which is controlled via a ripple switch or timeclock. When this rate is active the hotwater cylinder is heated also.
The other dial is the normal or high rate.
A bypass switch allowes the hotwater to be heated at the higher rate too.