Ask me about industrial electricity 2: electric boogaloo

The Something Awful Forums > Discussion > Ask/Tell > Ask me about industrial electricity 2: electric boogaloo

Noctone: Oct 25, 2005; XO til we overdose..

Umm that's a breaker panel, not a fuse box. And if I had to guess, I'd say that fan is some idiot's idea of moisture abatement.

# ¿ Jan 7, 2013 21:27

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# ¿ Apr 28, 2024 13:45

Noctone: Oct 25, 2005; XO til we overdose..

Can't wait to read about that in the inevitable OSHA fat/cat report. :xd:

# ¿ Jan 7, 2013 22:38

Noctone: Oct 25, 2005; XO til we overdose..

Only thing that immediately comes to mind for me is arc flash boundaries. Perhaps ladders/lifts/scaffolds, too, w/r/t overhead lines.

# ¿ Jan 24, 2013 14:59

Noctone: Oct 25, 2005; XO til we overdose..

Or you can get comical situations like my last job where management understands the necessity of arc flash and coordination studies but doesn't understand the technical complexity of them, and thinks a junior engineer with very little power systems experience can just pick it up in their spare time, at no cost, as an ancillary skill.

# ¿ Feb 2, 2013 01:12

Noctone: Oct 25, 2005; XO til we overdose..

I almost wonder if there was really a problem with the relay at all. Replacing it sounds like the kind of thing you do when you have a ton of public scrutiny hanging over your head and a bunch of powerful people who want answers. e: I mean really, if they had a false trip on the relay, why did it take so long for anyone to figure that out? I gotta imagine the maintenance staff are competent enough that the relay logs are the first thing they would check.

At any rate the whole thing is amusing to me, especially since I just spent the bulk of this week testing some SEL 351s and 587s for a substation.

Noctone fucked around with this message at 02:46 on Feb 9, 2013

# ¿ Feb 9, 2013 02:39

Noctone: Oct 25, 2005; XO til we overdose..

Controls is pretty huge and it's only going to get bigger. I can't think of a single controls engineer I know that has ever struggled to find work.

# ¿ Feb 9, 2013 18:50

Noctone: Oct 25, 2005; XO til we overdose..

Big Steveo posted:

I've worked maintenance for a railway in Australia specialising in substations. I can give limited info on protocols from our company, which may or may not be similar to the New Orleans authority

If the relay sensed a fault and tripped, the first thing the operator will do in the control room is determine whether the fault caused a lockout (MTM - Multiple trip Manual) or just a pain trip (MTA - Multiple trip Automatic). A MTM fault requires field staff to do a series of tests and clear the lockout at the substation manually. MTM faults are major faults. MTA is a minor fault like a short term overcurrent.

If there is no lockout the operating centre will try to reclose the breaker, if it opens again during a specific time period then it may lockout and field staff will be called out. I am assuming that like when we have special events there are staff located at important locations to rectify the fault, so would the New Orleans authority.

The first 10 or so minutes would be purely a conversation with the field staff and the operator on the nature of the fault, staff would then go and find the faulty equipment and fix it. Once a problem is fixed there would be a procedure in place to bring the feeder back online which can take time. So after 35-40 minutes after the fault occuring power was restored and a futher 10-15 minutes needed to warm up the lights again.

As I said before, I work in the industry and in another country. I do not have any inside knowledge about the workings in American power distribution. This is just a guess.

Nah that sounds about right. I was just saying the story sounded fishy and like some people were trying to cover their asses. And now that the relay manufacturer is saying that somebody hosed up the settings, I'm inclined to think I was right.

# ¿ Feb 10, 2013 05:09

Noctone: Oct 25, 2005; XO til we overdose..

Three-Phase posted:

I was reading that throughout the world there are varying voltages used in a lot of these trains - including DC and low-frequency AC. Voltages as low as 600VDC and as high as 25kVAC.

Whatever the voltage, if for any reason you find yourself standing on top of a train, never grab or go near the power wire. There's a video (that won't be linked to) of this on YouTube and Liveleak. In that case contact was believed to be instantaneously fatal.

Know exactly which video you're talking about :
https://www.youtube.com/watch?v=tjJdE_4tgfk

# ¿ Mar 4, 2013 02:04

Noctone: Oct 25, 2005; XO til we overdose..

slorb posted:

http://entergy-neworleans.com/content/superbowl/130202_Report.pdf

I wonder what other undocumented features S&C relays have. Yeesh.

Hahahahahaha this owns.

# ¿ Mar 29, 2013 04:33

Noctone: Oct 25, 2005; XO til we overdose..

Pretty sure there's like a 0.000001% chance that a power utility would give you that information. A lot of it is going to be proprietary and/or sensitive from a security perspective.

# ¿ Apr 18, 2013 02:02

Noctone: Oct 25, 2005; XO til we overdose..

Can't say with any certainty, but my best guess would be that it's a control house.

# ¿ Apr 19, 2013 02:48

Noctone: Oct 25, 2005; XO til we overdose..

Captain Foo posted:

I didn't even know "dry steam" was a thing

It's more jargon than a "scientific" term. "Wet" and "dry" steam are referring to the relative amount of condensate in the line.

# ¿ May 2, 2013 17:01

Noctone: Oct 25, 2005; XO til we overdose..

Three-Phase posted:

I think I've found a video showing the most spectacularly dangerous way to test a high-resistance grounded system.

If there was an undetected fault on another phase to ground, it would have probably blown up in this guy's face. Even more dangerous he could have accidentally gotten that cable between the phases leading to a potentially serious arc flash.

What I would have done if I had to test it this way: get a current-limiting fuse and fuseblock rated higher than the maximum short circuit current, and a contactor. Shutdown the system, LO/TO and cordon off the testing area, and rig the device to fault to ground via the contactor and the fuse. Then I could power the contactor from a safe distance away, and if for whatever reason there was a second undetected phase to ground fault, the fuse would open. (And even if the fuse failed the area would be cordoned and everyone would be a safe distance away.

In my opinion this is an absolutely Looney-Tunes test. A lot of people in the comments section seem to agree with me.

It looks like he's wearing garden/workshop gloves too.

We really need a psyduck/science combined GIF.

The entirety of that video my face was a combination of :psyduck:

and

# ¿ May 19, 2013 01:25

Noctone: Oct 25, 2005; XO til we overdose..

Pretty sure he was making a joke there and not asking a real question.

# ¿ May 20, 2013 23:12

Noctone: Oct 25, 2005; XO til we overdose..

I think you meant to say MV cables. :v:

Coincidentally, starting yesterday and continuing on for the next couple of months I'm testing a fuckton of 25kV cables and distribution equipment at a data center. Would take pics and/or videos but I'm prohibited from doing so per a confidentiality agreement.

# ¿ Jul 12, 2013 20:18

Noctone: Oct 25, 2005; XO til we overdose..

FrozenVent posted:

Insert NSA joke here.

Not this time but we have worked at an NSA data center before I think (but not me personally).

Three-Phase posted:

drat, I'm supposed to be the one to correct people on that!

To be fair, 25kV is HV according to some standards (NEC maybe? I forget.)

# ¿ Jul 12, 2013 21:55

Noctone: Oct 25, 2005; XO til we overdose..

I'm sure there are uses for a PE in electrical engineering, but my personal experience is pretty much what Three-Phase just said. Some places it helps with moving up the ladder because it's a hoop you can jump through that's easily identifiable to middle management. It definitely helps with finding job opportunities, I remember seeing it listed as a requirement or preference on a lot of job listings (even for jobs where a PE would be completely irrelevant). My employer pays out a $1,000 bonus for getting a PE (it's mostly intended for our studies engineers, but I could do it too), so I guess there's that too.

And Three-Phase that bad termination video is loving hilarious. Whoever made up those terminations should be fired, it's not really that difficult of a task. I tested thirty-three 5kV cables last week that were terminated by a kid who had never done them on his own before, and not a single one of them came even close to failing. Like, most of them were leaking less than a tenth of a microamp at 26 kVDC, which is really really good.

Noctone fucked around with this message at 01:26 on Jul 13, 2013

# ¿ Jul 13, 2013 01:23

Noctone: Oct 25, 2005; XO til we overdose..

Over the next three days my crew and I have to test 35 runs of 25kV cable (i.e. 105 individual cables) and 11 25kV S&C fused air switches.

:suicide:

One of the electricians for our client almost got his poo poo wrecked today. We were up at 78 kVDC on a cable from the MV switchgear to the MV switch, testing from the switchgear and dead-ending at the switch. Dude ducked underneath our danger tape and warning signs at the switch and opened up the door so he could take some pictures for idk what. :stonk:

Noctone fucked around with this message at 03:48 on Jul 19, 2013

# ¿ Jul 19, 2013 03:46

Noctone: Oct 25, 2005; XO til we overdose..

Hahahahaha figures. Ironically, electricians seem to keep their distance the most on low voltage circuit breaker testing, which is far and away the least dangerous thing we do (high current but very low voltage [7VAC or so], so the only danger is burning yourself on the cables/bus connecting the test set to the breakers).

# ¿ Jul 19, 2013 04:22

Noctone: Oct 25, 2005; XO til we overdose..

CF isn't so bad, at least card readers are still readily available. One of our IR cameras uses a PCMCIA memory card. :gibs:

# ¿ Sep 22, 2013 02:27

Noctone: Oct 25, 2005; XO til we overdose..

Remember how I said my company did some testing at an NSA datacenter? Yeah, about that...

Surprisingly I actually hadn't heard that these kind of issues were coming up.

One of our guys that worked there did severely injure his hands during an arc flash event...because he tried to check a medium-voltage switch dead with a low-voltage contact meter. :v:

# ¿ Oct 9, 2013 02:33

Noctone: Oct 25, 2005; XO til we overdose..

Three-Phase posted:

There was a YouTube video about a guy at a plant who was checking a 2400V motor starter using a regular low-voltage multimeter. The theory was he absentmindedly mistook it for a 480V starter somehow. The instant he touched the voltmeter leads on the A-line and B-load side of the fuses, the meter exploded and cause an arc flash in the breaker. He was blown across the isle and slammed into the gear several feet away. He eventually made it to an office to get first aid, but he left a trail of burned clothing and melted tools in his wake. He was conscious and muttered "I messed up". He later died in the hospital from the severe burns.

The cubicle and breaker were destroyed in the incident. It's still part of the 2400V lineup, but the equipment was removed and there's a memorial plaque bolted on the cubicle door.

Charlie Morecraft spoke where I worked several years ago. He wasn't in an arc flash but a fire at a refinery. You could hear a pin drop in the auditorium when he was speaking and explaining all the stuff that happens when you get third-degree burns. You had big, tough guys who were cowering when he talked about things like skin debridement.

Yeah I was really surprised when I heard about it, he didn't have any scars or lack of functionality that I could see. Lucky bastard if there ever was one.

I asked one of my coworkers that spent a lot of time at the NSA datacenter what the deal is with the arc flash incidents, but he didn't really know anything either.

# ¿ Oct 9, 2013 15:45

Noctone: Oct 25, 2005; XO til we overdose..

I think he was being intentionally hyperbolic. Very rarely will you find a 20A breaker in a panel/switchboard that merits even an HRC 2. In a general sense, sure as poo poo people wear PPE for switching molded case circuit breakers (as well they should).

# ¿ Oct 15, 2013 05:13

Noctone: Oct 25, 2005; XO til we overdose..

You do arc flash assessments for a living and you're asking this? :psyduck:

# ¿ Oct 15, 2013 06:15

Noctone: Oct 25, 2005; XO til we overdose..

Pvt Dancer posted:

Why not? Wearing PPE for something with neglible risk is doing it wrong.

Well first of all I said in general, because molded case circuit breakers do cover quite a range.

But, yes, there are situations where it's definitely a good idea to wear PPE to do switching on a 20A breaker. 120/208 panelboard? Probably not, as I mentioned before. 480 or greater? Lot more likely. A tripped feeder breaker on a switchboard with a high available fault current is a closed-casket funeral waiting to happen.

# ¿ Oct 15, 2013 14:53

Noctone: Oct 25, 2005; XO til we overdose..

Ohhhhhh I see what you've been getting at. Yeah, I've definitely heard of places that require PPE for any and all switching regardless of the actual hazard and/or risk. It's dumb and leads to exactly what you mentioned.

# ¿ Oct 15, 2013 16:13

Noctone: Oct 25, 2005; XO til we overdose..

Groda posted:

No, I'm pretty sure you're mistaken.

Do tell.

# ¿ Dec 23, 2013 19:34

Noctone: Oct 25, 2005; XO til we overdose..

Even if what you're saying is true (which I highly doubt and can't find any reference to), it doesn't invalidate enilev's post.

# ¿ Dec 23, 2013 21:19

Noctone: Oct 25, 2005; XO til we overdose..

Speaking of bad engineering: So right now I'm doing some testing at a new 115/230 kV switchyard for an hydroelectric dam generating facility. Today we were doing some functional testing and discovered that the Local/Remote switch at each HV breaker completely bypasses all protection schemes associated with the breaker (including both the breaker and bus 86 lockouts) when it is in Local. This is by design.

:negative:

# ¿ Jul 25, 2014 04:40

Noctone: Oct 25, 2005; XO til we overdose..

Three-Phase posted:

I had a design issue with the trip/close strings for a high voltage breaker that also involved a local/remote control selector. I can't remember the exact issue. It might have been a sneak circuit.

Bypassing protection is pretty crazy - I take it they want to operate the breaker when it's isolated (for testing general operation and timing of the contacts opening and closing) and don't want it to trip free?

Not really sure what their reasoning is but apparently for now they want to keep it that way. :geno:

some texas redneck posted:

So there was a pretty awesome thunderstorm overnight. Got to drive home in it. Tons of nearby strikes, some too close for comfort even in a car (watching the morning news now, there were several fires in the immediate area I was driving through attributed to lightning).

Lightning hit a nearby line, and I saw what could best be described as a Jacob's Ladder... except it was travelling down the line until it hit the next pole. I guess it shorted to ground at that point, as there was a nice big boom and all the power for about a block went out.

It was ~~pretty~~ loving awesome to see, but what the gently caress was it? I knew enough not to look directly at the arc, and put on my sunglasses while I was watching it (Oakleys, decent UV protection).

It was at least a 13.2kV line, likely higher given the industrial area.

My best guess would be that the lightning strike produced enough of a voltage spike to cause a phase-to-phase fault between the conductors (through the air) and the arc propagated down the line until it hit the pole and faulted to ground.

As a side note, I'd be mildly surprised if the line was any greater than 13.8. Almost every industrial or commercial site I've been to has been 13.2 or 13.8. About the only places where I see higher voltages than that are data centers, where 24.9 and 34.5 are pretty common (usually only see 34.5 at very large data centers).

Noctone fucked around with this message at 17:04 on Jul 31, 2014

# ¿ Jul 31, 2014 17:01

Noctone: Oct 25, 2005; XO til we overdose..

KaiserBen posted:

That's nothing; we're putting in some 47MW motors later this year. VFDs for them too.

I'm going to a job site the next couple weeks where they'll have a couple of multi-MW Solar generators just as temporary stand-in feeds for doing functional tests.

# ¿ Aug 13, 2014 05:23

Noctone: Oct 25, 2005; XO til we overdose..

No.

# ¿ Aug 16, 2014 04:07

Noctone: Oct 25, 2005; XO til we overdose..

I'm looking at the user's guide right now and there's a fairly thorough explanation of the binary search macro in Appendix C. Do you not have that document?

Also which function are you trying to test?

# ¿ Aug 28, 2014 15:12

Noctone: Oct 25, 2005; XO til we overdose..

Yes.

# ¿ Sep 11, 2014 04:12

Noctone: Oct 25, 2005; XO til we overdose..

Definitely not a power station.

# ¿ Jan 14, 2015 09:39

Noctone: Oct 25, 2005; XO til we overdose..

If you run into more issues I might be able to help by taking a look at our RTS routine for the 311L. Don't have a routine for the 90L, unfortunately.

# ¿ Jan 28, 2015 16:51

Noctone: Oct 25, 2005; XO til we overdose..

So Doble bought ENOSERV.

# ¿ Jan 29, 2015 17:21

Noctone: Oct 25, 2005; XO til we overdose..

Nah, field engineer for a testing company. We mostly use RTS for relay testing.

# ¿ Mar 18, 2015 18:14

Noctone: Oct 25, 2005; XO til we overdose..

I really hope that just means the equipment was retired.

# ¿ May 23, 2015 04:18

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# ¿ Apr 28, 2024 13:45

Noctone: Oct 25, 2005; XO til we overdose..

Those dudes must be living in their own tiny little world then, because I've never heard anyone use "megger" as a lowercase noun/verb to refer to anything other than insulation resistance test sets/testing. It's like Kleenex and facial tissues.

# ¿ Jun 11, 2015 19:16

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