Hoover Dam Explosion

oldfieldguy (Electrical)

(OP)

19 Jul 22 21:36

Looks like a transformer let go.

Link

old field guy

RE: Hoover Dam Explosion

hokie66 (Structural) 19 Jul 22 21:49

So? Not a big deal.

RE: Hoover Dam Explosion

oldfieldguy (Electrical)

(OP)

19 Jul 22 22:24

hokie66-

You know that and I know that, but it made the news cycle. I don't think it was much of a transformer, judging from the smoke cloud.

OFG

old field guy

RE: Hoover Dam Explosion

Sym P. le (Mechanical) 19 Jul 22 23:26

Fortunately, there wasn't enough water behind the dam to put out the fire.

RE: Hoover Dam Explosion

cvg (Civil/Environmental) 19 Jul 22 23:35

not sure water is recommended on an electrical fire

RE: Hoover Dam Explosion

dik (Structural) 20 Jul 22 04:04

it's OK, there isn't any... lol

Actually, I think they have about ~~50'~~ 100' to go...

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Hoover Dam Explosion

JohnRBaker (Mechanical) 20 Jul 22 04:22

Yea, they played it up on the local news but as anyone could see, it was just a transformer and the photos taken afterwards didn't really show all that much damage, just a lot of soot and foam covering the area.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Hoover Dam Explosion

itsmoked (Electrical) 20 Jul 22 05:19

THS
.
.
.
.
Transformer Heat Stroke

It's over 102F (39C) there every day at the moment.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Hoover Dam Explosion

TugboatEng (Marine/Ocean) 20 Jul 22 05:33

They surely designed for a higher ambient temp in that location. 40°C is the standard ambient design for electrical machines and there are 50-65°C standards. We do 50°C for marine applications.

RE: Hoover Dam Explosion

FacEngrPE (Mechanical) 20 Jul 22 08:11

Are those the same transformers installed in 1935?

Look closely, Transformer has only left 2 bushings, right bushing you can see the power line leaving, but not the right bushing.

RE: Hoover Dam Explosion

cranky108 (Electrical) 20 Jul 22 14:12

Too bad transformer deliveries are up to three years.

RE: Hoover Dam Explosion

spsalso (Electrical) 20 Jul 22 14:41

Probably doesn't need replacement, but repair in place.

spsalso

RE: Hoover Dam Explosion

JohnRBaker (Mechanical) 20 Jul 22 15:26

Yes, that Right phase line looks like where all the action was. The insulator at the bottom of the power line leaving the station is all covered in soot and, as you noticed, the line from the transformer is missing.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Hoover Dam Explosion

itsmoked (Electrical) 21 Jul 22 10:21

How is there a big red manifold with sprayers up on the wall just for that one transformer??

Keith Cress
kcress - http://www.flaminsystems.com

RE: Hoover Dam Explosion

cranky108 (Electrical) 21 Jul 22 15:16

Soaker hose cooling system?

RE: Hoover Dam Explosion

TugboatEng (Marine/Ocean) 21 Jul 22 15:29

The transformer is different from the rest. Perhaps it has a flammable oil and the others do not.

RE: Hoover Dam Explosion

cranky108 (Electrical) 21 Jul 22 15:45

What transformer oil is not flammable?

RE: Hoover Dam Explosion

TugboatEng (Marine/Ocean) 21 Jul 22 16:15

Good question I guess. I assumed PCB's as well as other halogenated oils to be non-flammable but that appears to not be the case.

RE: Hoover Dam Explosion

FacEngrPE (Mechanical) 21 Jul 22 21:37

I don't think non/less flammable oil helps much in case of a high energy fault. It does limit the fire damage after the protection stops the arcing fault.

Quote (https://www.transformer-technology.com/community-h...)
According to studies, bushings cause 17% of all power transformer failures and are the third most common reason for transformer breakdowns. High-voltage bushings contribute 30% to all fires and explosions associated with power transformer breakdowns.

RE: Hoover Dam Explosion

JohnRBaker (Mechanical) 21 Jul 22 21:43

Since it appears that one of the bushings is 'missing' and the insulator that was securing that right-side phase line appears to be heavily charred and which would have been close to said bushing, it would seem that the bushing was indeed 'involved' in whatever happened.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Hoover Dam Explosion

dik (Structural) 21 Jul 22 22:25

That's what I thought, but I didn't notice it was missing until someone mentioned it... an electrical HV engineer informed me that activity was 'hotter than the sun'.

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Hoover Dam Explosion

TugboatEng (Marine/Ocean) 22 Jul 22 01:21

Halocarbons, including fire extinguishing agents do start to decompose above 1000°F or so. They are burning and give off some nasty fumes in the process. An electric arc is 10x that temp.

RE: Hoover Dam Explosion

dik (Structural) 22 Jul 22 01:50

It was only about 5 years back that I learned that... and had to check his answer... I didn't think it was possible... ponder

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Hoover Dam Explosion

spsalso (Electrical) 22 Jul 22 03:50

The coolest part of the sun is about 10,000 F.

Hottest is 27,000,000 F.

So I guess it depends where you choose to take your vacation.

spsalso

RE: Hoover Dam Explosion

cranky108 (Electrical) 25 Jul 22 16:07

I would only go there at night. It is much cooler.

I have heard of dry type transformers, and SF6 cooled transformers, but I don't know of any power companies that currently use them for generator GSU's or aux transformers.

But you know things do fail. And with the lack of water, it is likely that any one unit could be taken off line without a constraint that the water level doesn't already offer.

RE: Hoover Dam Explosion

FacEngrPE (Mechanical) 25 Jul 22 21:26

As some point the water gets to low to spin the turbine.

Quote (https://en.wikipedia.org/wiki/Hoover_Dam)
Under its original design, the dam would no longer be able to generate power once the water level fell below 1,050 feet (320 m), which might have occurred in 2017 had water restrictions not been enforced. To lower the minimum power pool elevation from 1,050 to 950 feet (320 to 290 m), five wide-head turbines, designed to work efficiently with less flow, were installed.[102] Water levels were maintained at over 1,075 feet (328 m) in 2018 and 2019,[103] but fell to a new record low of 1,071.55 feet (326.61 m) on June 10, 2021[104] and were projected to fall below 1,066 feet (325 m) by the end of 2021.[105]

LOWER COLORADO RIVER DAILY REPORT: Current Month (Daily Data)
If I read the report correctly, current pool elevation is 1040.69 ft

RE: Hoover Dam Explosion

dik (Structural) 25 Jul 22 21:56

I understand that happens if it drops another 100' and at 150' the river stops flowing...

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

RE: Hoover Dam Explosion

cranky108 (Electrical) 26 Jul 22 13:10

The good news is that the tail race level likely will not limit any power production.

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Hoover Dam Explosion