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11kV lines down #122936
02/09/06 11:51 PM
02/09/06 11:51 PM
Trumpy  Offline
Joined: Jul 2002
Posts: 8,260
SI,New Zealand
Photos and info submitted by RODALCO:

11 kV lines down at 753 Te Atatu rd, Te Atatu North during storm on 24.01.2006 around 16.00 hrs, 4 km from Te Atatu sub. on Harbour view feeder. Earth fault protection failed hence the damage.
185mm² Al cock roach till 1 span before ABS 638 then Cu 16mm² for the next 1.5 km's.
This is a non fused section on a 400 Amp feeder at the end of a long suburban feeder. By this ABS 4 spans of 11 kV were down and another 4 separate spans at the end of this line.
Amazingly no damage was done to the 230 / 400 volts services which I had inspected by a contract inspector during the repairs.
Power was restored at around 01.30 hrs.
25 transformers were off and about 1500 customers affected.

[Linked Image]

ABS 638 minus its 11 kV wires:

[Linked Image]

Melted cables, the storm hasn't even started to full power yet:

[Linked Image]

Melted 16mm² Cu O/H cable:

[Linked Image]

Burn marks in the grass:

[Linked Image]

[Linked Image]

[This message has been edited by Trumpy (edited 02-09-2006).]

Tools for Electricians:
Re: 11kV lines down #122937
02/10/06 12:10 AM
02/10/06 12:10 AM
Trumpy  Offline
Joined: Jul 2002
Posts: 8,260
SI,New Zealand
2nd part of post:

ABS 638 other side:

[Linked Image]

Burnt through 15 cm conctere driveway. ( NZ 20 cent piece):

[Linked Image]

[b]Other close up from burned concrete:

[Linked Image]

Damaged drive way from Tasti Products:

[Linked Image]

My apologies for the delay posting this thread,
I haven't had a working computer for a wee while. [Linked Image]

[This message has been edited by Trumpy (edited 02-10-2006).]

Re: 11kV lines down #122938
02/10/06 12:26 AM
02/10/06 12:26 AM
Radar  Offline
Joined: Apr 2004
Posts: 349
Los Angeles, CA
Wowzers this stuff is amazing. I live in a neighborhood with 12KV OH lines, old ones too. You know, the kind that fall occasionally in wind storms. Luckily none of the 12KV runs thru my yard, but one fell in my across-the-street neighbor's back yard a few years ago. Almost landed in his pool. It relayed off and on and off again before locking out, lots of arc marks on and around the house.


There are 10 types of people. Those who know binary, and those who don't.
Re: 11kV lines down #122939
02/10/06 01:48 AM
02/10/06 01:48 AM
Dave T  Offline
Joined: Jan 2005
Posts: 155
Waukesha, WI, USA
I remember years ago when I had the privilege to see a downed line burn through a concrete sidewalk. That certainly got my attention.

Re: 11kV lines down #122940
02/10/06 11:11 AM
02/10/06 11:11 AM
pauluk  Offline
Joined: Aug 2001
Posts: 7,520
Norfolk, England
I wouldn't have wanted to be standing anywhere around there when those lines came down! [Linked Image]

Re: 11kV lines down #122941
02/10/06 02:25 PM
02/10/06 02:25 PM
John Crighton  Offline
Joined: May 2005
Posts: 177
Southern California
It must have been an impressive light show, with all that arc welding going on. Too bad there were no surveillance cameras in the neighborhood.

Re: 11kV lines down #122942
02/10/06 06:23 PM
02/10/06 06:23 PM
Rewired  Offline
Joined: Jan 2006
Posts: 558
Hamilton, Ontario, Canada
Wow! It really makes you take a step back and think about the amount of energy that can be delivered over a couple of measley conductors.. In my city the O/H ranges anywhere from 4KV all the way up to 27.6 KV.. We once had a 4KV circuit knocked down just behind my house but it didn't trip the substation breaker and did not arc or spark at all but was still hot!..
Someone actually tried to move this hot wire off their driveway with a dry pice of wood just so they could get their car out... It didn't work as they recieved a good shock but it did not harm them thank God!
Some people just do not understand!


Re: 11kV lines down #122943
02/10/06 09:55 PM
02/10/06 09:55 PM
Lostazhell  Offline
Joined: Feb 2004
Posts: 1,431
Bakersfield, CA (Originally Or...
I once worked on a house where a 12KV primary broke loose and landed on the home's service drop.. Crazy things happened there! The 86 year old homeowner told me she was just sitting in her rocking chair and it sounded like someone fired a cannon in her backyard! GFI's with the faces blown off, the panel had a hole blown through the back (FPE), but strangely, some appliances survived.. others just made blue smoke when we tried plugging them into a generator.

Another time I happen to be around when 2- 33KV lines lost to gravity north of downtown Los Angeles in a storm... The arc-blast was enormous enough that the streets dept had to spot repair where the lines had fallen on the street (asphalt), where they had hit the sidewalk (concrete) it looked like it turned it to glass!


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