ECN Forum Forums General Topics of the Trade Non-US Electrical Systems & Trades Powercut in Auckland affecting 258,000 customers

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.