hadron collider 18kV failure

[avogel]

The science blog also posted an explanation from CERN spokeswoman Renilde Vanden Broeck, who explained a cable fault caused the failure in the 18 kV power supply network, which affected mainly the Meyrin site where the LHC is located, and in particular the injectors and the Computing Centre but not the LHC cryogenics. “The network was back up by 10:30 a.m. As there were knock-on effects it took time to get everything back up (the LHC etc. is a complex electrical system),” she wrote. “Power cuts are not that rare around here. There was again beam in the machine at 10:30 p.m. last night."

So I wonder if these nuclear physicists are a bit behind on cable testing practices. A comment like power failures are not that rare for a new $10 Billion accelerator seems odd to me!

 

[ScottyUK]

Depends where the power comes from - do they have on-site generation, or are they dependant on the utility network?


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If we learn from our mistakes I'm getting a great education!

 

[avogel]

I remember there was an IEEE Spectrum article on it awhile back, they seemed to be connected to both the French and Switz grids and ran somewhere inbetween 220 and 300 MW. but, this failure didn't have anything to do with where their power comes from, from the pictures it looked like a termination on a feeder in one of their switchgear.

 

[ScottyUK]

That's big load for one facility.

Agreed, looks like an MV switchgear termination problem.

I was just curious if her comment was really that 'equipment failures' aren't that rare, or 'power outages from the utility' aren't that rare.

Look what happens when spokespeople get involved: People who understand stuff start getting confused, and those who understand none of it start to know everything...


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If we learn from our mistakes I'm getting a great education!

 

[amptramp]

I doubt any nuclear physicists are terminating stress cones on HV cables...

 

[EEJaime]

How could this fail?

According to Leonard Susskind in Black Hole War, all of this, the energy, the LHC, the terminations, you, me, etc..., all of it-is nothing more than information anyway. Maybe someone forgot to inform the cable?

 

[amptramp]

Yeah, but since information is conserved (currently), into what black hole did all the smoke go ...

 

[oldfieldguy]

Looks like what happens when somebody does a poor job on a stress cone/termination.

In all the years I've tested and installed MV cables (hundreds), I've never had one do that after a "good" test. I've terribly inconvenienced some people by telling them that one of their stress cone installations was "less than optimum" and recommended it be removed and reworked.

Oh, well...

old field guy

 

[amptramp]

oldfieldguy:

In an effort to learn something, what constitutes a poor job on a stress cone termination? Thanks.

 

[Zogzog]

"I doubt any nuclear physicists are terminating stress cones on HV cables... "

I am a nuclear engineer and have done hundreds of MV cable tests and terminations.

 

[oldfieldguy]

amptramp:

Good question.

1. Know what you're doing. I follwed a crew that didn't remove the semi-conducting layer before applying the termination kit. "We was readin' about that "semi-con" an' all we saw as black rubber. We thought our cable was different from the instructions." I found this little fauz pas in acceptance testing with a DC hipot.

2. Follow the instructions with the termination kit you're actually using. I failed a whole set (two conductors per phase, three phases) that didn't pass the acceptance test. The electrician "knew what he was doing" and didn't need the instructions. Except what he "knew" was from a different type of termination kit.

3. Keep things clean and dry, including the hands (or gloves) of the electrician applying the kit. The skin oils and sweat from the electrician can form a path invisible to the naked eye. High voltage electricity will find that path, though, and over a period of time, the path will begin to heat and carbonize, until one day...




old field guy

 

[amptramp]

Zogzog:

Is a nuclear engineer the same thing as a nuclear physicist?

oldfieldguy:

Thanks for the info.

 

[EEJaime]

oldfieldguy, I get the name, but I am pretty sure you have not actually been doing this for hundreds of years:

"In all the years I've tested and installed MV cables (hundreds)"

Or..., you must be really, really good at this by now.

Just kidding, have a good day.

EEJaime