The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Locked rotor, no burnout
by andey
Today at 04:48 AM
Temporarily feeding a panel...
by Potseal
Yesterday at 11:05 PM
Massive power outage South Australia
by Meadow
Yesterday at 06:46 AM
short circuit??
by Meadow
Yesterday at 06:43 AM
Norwegian power?
by Meadow
Yesterday at 06:36 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 14
sparky 10
sparky66wv 8
gfretwell 8
Potseal 7
Who's Online
0 registered (), 300 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Page 1 of 2 1 2 >
Topic Options
Rate This Topic
#189941 - 10/30/09 12:57 AM Powercut in Auckland affecting 258,000 customers
RODALCO Offline
Member

Registered: 12/08/05
Posts: 862
Loc: Titirangi, Akld, New Zealand
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
_________________________
The product of rotation, excitation and flux produces electricty.

Top
Test Equipment:

Large Selection of Test Equipment For Electrical, HVAC, Test & Measurement
Large Selection of Test Equipment For Electrical, HVAC, Test & Measurement

#189944 - 10/30/09 01:13 AM Re: Powercut in Auckland affecting 258,000 customers [Re: RODALCO]
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8530
Loc: SI,New Zealand
Woah!,
Our lights seemed a lot brighter down here in the South Island today. grin
We even shut 3 generation stations down and had Benmore idling. yay

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.
whistle
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

Top
#189945 - 10/30/09 01:35 AM Re: Powercut in Auckland affecting 258,000 customers [Re: Trumpy]
RODALCO Offline
Member

Registered: 12/08/05
Posts: 862
Loc: Titirangi, Akld, New Zealand
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.
_________________________
The product of rotation, excitation and flux produces electricty.

Top
#189946 - 10/30/09 01:41 AM Re: Powercut in Auckland affecting 258,000 customers [Re: RODALCO]
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8530
Loc: SI,New Zealand
Ray,
I hope you realise that most of what I posted above was in sarcasm. cheers

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.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

Top
#189947 - 10/30/09 01:56 AM Re: Powercut in Auckland affecting 258,000 customers [Re: Trumpy]
RODALCO Offline
Member

Registered: 12/08/05
Posts: 862
Loc: Titirangi, Akld, New Zealand
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.
_________________________
The product of rotation, excitation and flux produces electricty.

Top
#189994 - 11/01/09 08:28 PM Re: Powercut in Auckland affecting 258,000 customers [Re: RODALCO]
mbhydro Offline
Member

Registered: 02/21/03
Posts: 340
Loc: Winnipeg MB Canada
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.

Top
#190047 - 11/04/09 03:55 AM Re: Powercut in Auckland affecting 258,000 customers [Re: mbhydro]
RODALCO Offline
Member

Registered: 12/08/05
Posts: 862
Loc: Titirangi, Akld, New Zealand
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.
_________________________
The product of rotation, excitation and flux produces electricty.

Top
#190055 - 11/04/09 11:09 AM Re: Powercut in Auckland affecting 258,000 customers [Re: RODALCO]
LarryC Offline
Member

Registered: 07/05/04
Posts: 775
Loc: Winchester, NH, US
Quote:
a large shipping container was within the safe M.A.D. of one of the main 220 kV lines.


What is a M.A.D ?

Top
#190057 - 11/04/09 12:14 PM Re: Powercut in Auckland affecting 258,000 customers [Re: LarryC]
ghost307 Offline
Member

Registered: 05/09/05
Posts: 877
Loc: Chicago Illinois USA
Minimum Approach Distance??
_________________________
Ghost307

Top
#190346 - 11/11/09 10:03 PM Re: Powercut in Auckland affecting 258,000 customers [Re: ghost307]
OldAppy Offline
Member

Registered: 08/06/06
Posts: 27
Loc: Titirangi, AKLD, NZ
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


Edited by OldAppy (11/11/09 10:04 PM)

Top
Page 1 of 2 1 2 >



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals