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grover posted:I love how that guy puts on all that arc-flash gear yet doesn't bother to properly velcro the front of his suit, leaving it hang open. "closing 4160 volt breaker with arc flash PPE on backwards and under rated" It's hard to see, but on the panels above the breaker below the 269 Multilins, the "ON" light and button is red, and the "OFF" light is green with a black button. I've heard of facilities with both "green means go" and "green means safe" color schemes. In this scheme, red indicates the system is on/energized and is used to imply danger. Found a video from ABB on their Arc resistant switchgear that's pretty neat. The other solution that I saw from Siemens was selling GIS switchgear for medium voltage (4160-33kV I believe). Three-Phase fucked around with this message at 12:07 on Apr 7, 2012 |
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Apr 7, 2012 11:53
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The low voltage compartment also works well as a place to keep your beer while racking a breaker.
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Apr 7, 2012 12:49
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Guy Axlerod posted:The low voltage compartment also works well as a place to keep your beer while racking a breaker. I love trade shows.
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Apr 7, 2012 13:05
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Three-Phase posted:It looks like, using his right arm, he reaches in and manipulates something, then reaches back in, and as his arm reaches the end of motion, the arc flash occurs. What is funny/creepy: after the arc flash, there does appear to be a worker nonchalantly walking behind the panel that just had an arc flash and is spewing smoke like nothing unusual has happened. Maybe at this workplace this is what nothing unusual happening looks like. With the arc-resistant switchgear, why have the panel on the same chassis as the medium-voltage gear? It seems like with some longer wires it could be in a nice air-conditioned control room. Also, are dapper bow-ties included or must they be ordered separately? Frozen Horse fucked around with this message at 08:56 on Apr 9, 2012 |
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Apr 9, 2012 08:50
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Frozen Horse posted:Maybe at this workplace this is what nothing unusual happening looks like. There is probably a lot of things in there they traditionally want to keep close to the breaker. Having long wires going to a remote location from a piece of equipment sounds fine and dandy until you need to work on the equipment. I have seen installations where the bus PTs and line CTs are sent into a control room where the protective relaying is. The problem is that the circuitry to look at the position of the breaker, and the trip/close/elevate/lower commands still need wiring right by the breaker. In many facilities, the status of the breaker is sent to a PLC or RIO system. That data would include: Breaker position (racked in or out) Control power status (may also be two statuses, one for the close circuit and one for the trip circuit) Breaker position (closed or opened) Switchgear door status (closed or opened) Assuming all the permissives are in place, you can also send a signal to close or open a circuit breaker via the PLC/SCADA system. However, in some systems you have lockout relays - if the breaker trips for some reason besides a trip command, the operator must physically go out to the breaker and flip a switch to disable the lockout before trying to close the breaker. The operator can't just hit the CLOSE BREAKER button on their computer. The idea there is it forces the personell to basically go to the breaker and make sure there isn't anything blatantly wrong or unusual. . Also, in many facilities, you don't necessarily need keys to open up a piece of equipment that can easily kill you. In many places if you're in a facility or on a factory floor, it's assumed that since you're there, you understand that opening up a cabinet with a "DANGER! HIGH VOLTAGE!" sign on it may lead to death. If you're at an institution like a school, business, or place with less than completely controlled access, that stuff would be locked away in a separate room. In a factory, I've seen metal-clad switchgear just sitting out on the shop floor. (Usually with warning signs and a "don't hang around close to me" tape on the floor around it.) Frozen Horse posted:Also, are dapper bow-ties included or must they be ordered separately? As a fun little aside - I've heard of some factories where ties are strictly prohibited, at least on the factory floor (must be removed or safely "tucked inside" a person's shirt). The reason being that with moving and rotating machinery, a tie can catch and fling/strangle/pull in a victim. The spinning rotor of even a small motor and anything connected to the shaft must be treated with the utmost respect. Even when coasting down the momentum of a large rotor weighing thousands of pounds can easily and violently tear apart an entangled victim. Three-Phase fucked around with this message at 20:42 on Apr 9, 2012 |
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Apr 9, 2012 11:40
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Three-Phase posted:As a fun little aside - I've heard of some factories where ties are strictly prohibited, at least on the factory floor (must be removed or safely "tucked inside" a person's shirt). The reason being that with moving and rotating machinery, a tie can catch and fling/strangle/pull in a victim.
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Apr 9, 2012 22:07
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grover posted:Legend has it that clip-on-ties were invented for safety. Specifically, I've heard of IBM having a tear-away tie designed to prevent their field service technicians from getting pulled into the paper feed of their printers. This from back when field service technicians were expected to wear ties, and the printers involved were attached to early mainframe computers capable of handling data fast enough to print out phone bills for the Chicago area each month. No mere desktop printer, those.
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Apr 9, 2012 22:33
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I was going to make a post saying that the bow-tie was part of the necessary PPE, but you beat me to it and with a good reason even. I work on printers myself, and would agree that ties do not belong anywhere near a roll-feed printer.
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Apr 9, 2012 22:52
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That reminds me - one of the most important tools used at my job: The laser plotter I see (and make) lots of prints in C and D size. There are still workplaces that have separate people who do CAD work, but nowadays it seems like any engineer or technician needs to at least have a year or so's experience in AutoCAD. Occasionally large color-coded layouts, diagrams, and Gantt charts get plotted on special color plotters that are oversized inkjet printers. E-paper in C or D size would be nice, but it would have to withstand oil, metal chips, dust, scratches and punctures, very high and low temperatures, and be vibration resistant to take the place of paper prints in an industrial environment.
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Apr 10, 2012 00:56
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Three-Phase posted:I see (and make) lots of prints in C and D size.  We do have an inkjet plotter cable of full-size color prints, but it's sooo slow. I've actually come to prefer A-size to half-size because it's way more convenient to store & carry. There are some drawings just need to be really huge to be intelligible, though. Especially when the draftsman ignored all standards and used the smallest font possible.
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Apr 10, 2012 02:21
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http://www.ecowattplug.com/p/63/ecopac Someone asked me today on whether or not this was a good deal. How people can get away with making such statements is beyond me. Meters don't even bill kVA, they only bill kW... Cheesemaster200 fucked around with this message at 18:11 on Apr 16, 2012 |
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Apr 16, 2012 18:08
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Cheesemaster200 posted:http://www.ecowattplug.com/p/63/ecopac Unfortunately for legal reasons I'm not going to make statements about the products. This is my personal view - any extraordinary claims require extraordinary evidence or explanation. Three-Phase fucked around with this message at 00:09 on Apr 17, 2012 |
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Apr 16, 2012 22:14
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Well... poo poo, then I guess I'll ask. How would fixing power factor help anyone directly if their utility doesn't measure their power factor their home in one way or another. Don't cap banks draw some extra power? Wouldn't any savings on power factor have to be negotiated with the utility anyways? Also, don't the utilities measure the power factor from the substation?
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Apr 17, 2012 04:17
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It's burgin' time! 
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Three-Phase posted:Unfortunately for legal reasons I'm not going to make statements about the products.
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Apr 18, 2012 00:11
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I heart bacon posted:Don't cap banks draw some extra power? A purely capacitive load would only draw reactive (leading) power, with some miniscule amount of real power through any parasitic resistance. That leading power would cancel out lagging power consumed by inductive loads like induction motors. I've only seen capacitor banks in industrial systems that have massive inductive loads. The problems I've seen with capacitor banks is they need to be applied very carefully. Closing in a massive capacitor bank can cause a voltage transient that can do things like crash electronics. The transient is a suddent spike, and then it decays down into a ringing (probably around a few hundred hertz) that fades out within two or three cycles. Three-Phase fucked around with this message at 23:05 on Apr 18, 2012 |
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Apr 18, 2012 22:59
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Capactitor banks are also used to allow induction generators (windmills) to take the required 30% reactive load. Most windfarms have huge banks that can fail in very spectacular ways.
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Apr 19, 2012 19:40
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helno posted:Capactitor banks are also used to allow induction generators (windmills) to take the required 30% reactive load. Any chance you can link to any pics or videos?
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Apr 19, 2012 19:48
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A pole-mounted capacitor bank failed rather spectacularly about 2 months ago about 2 blocks from here. Scared the poo poo out of me since I was all of about 25 ft away on a sidewalk (1 pole away on the same side of the road). Probably the fastest I've ever run. Just picture a shitload of sparks and a bunch of loud-rear end KABOOMS followed by the power going off and on for a couple of hours until the power company finally wanders out to disconnect it. At least I found out how fast the generators on campus fire up... and shut down... and fire up again.. repeat for a couple of hours. It did the typical "reclose twice then lock out" bit, but after 15 minutes the power would come back on for a few seconds and the whole cycle would repeat until whatever breaker locked out again. Oh, it's still disconnected. My UPS kicks in a lot more often since then, go figure. No I'm not pissy about my lovely smaller city municipal electric. Nor am I pissed at not being able to use their emergency line if the # you're calling from isn't recognized as one of their customers. 
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Apr 20, 2012 04:48
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some texas redneck posted:No I'm not pissy about my lovely smaller city municipal electric. Nor am I pissed at not being able to use their emergency line if the # you're calling from isn't recognized as one of their customers. Yeah, I've found the emergency reporting leaves something to be desired in a lot of situations. That generator starting/stopping is a problem. You would think that the emergency system would be configured to run for a few minutes after it detects power has been restored so that it doesn't keep stopping and restarting the generators. The disconnect switches I've seen have a timer where the power must be restored for like at least 15 seconds before it switches over then shuts down the generators. The problem too is that generators I've seen have a cool-down period where you command them to shut down, and I think what it does is run the generator for sixty seconds or so with no load and then it turns off the engine. This is for smaller 100-250kVA generators. Do generators have a starts per hour lockout? I could see that for some generators, except ones feeding mission critical loads where they'd rather possibly destroy the generator than stop powering the loads.
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Apr 20, 2012 17:02
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Three-Phase posted:Yeah, I've found the emergency reporting leaves something to be desired in a lot of situations. If they were actually starting up/shutting in rapid succession like that, they were set horribly wrong. In this size range diesel gen, they can start and come up to RPM and voltage in about a second and shut down very quickly as well. They shouldn't be doing it repeatedly, though! grover fucked around with this message at 19:47 on Apr 20, 2012 |
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Apr 20, 2012 17:12
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I'm a junior EE student and I recently got an internship at the local utility. The job is kind of lame (analyzing large amounts of data for improving substation performance) but hopefully it will be my foot in the door to getting a design-type job. My internship last year was in integrated circuit design, so I'm kind of all over the map right now. What is the market like for power engineers right now (my full-time job hunt starts this fall)? It seems to me like a solid industry to get into in the United States, since energy is a hot thing right now and you can't really outsource our utilities. The semiconductor industry, on the other hand, seems like a sinking ship in the United Stats, where only the super elite can find jobs with the titans like Intel, Texas Instruments, Qualcomm, etc. Also, is getting a masters in EE for power a good idea? alwayslost fucked around with this message at 17:38 on Apr 20, 2012 |
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Apr 20, 2012 17:33
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Electrical porn: one of ITER's (the fusion project going on in the south of France) press releases this morning was on the their switchyard. Plus a technical presentation if you're so inclined. 400kV supply, 500MW pulsed draw and a short circuit power of 10GVA 
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Apr 20, 2012 19:22
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grover posted:If they were actually starting up/shutting down, they were set horribly wrong. In this size range diesel gen, they can start and come up to RPM and voltage in about a second and shut down very quickly as well. They shouldn't be doing it repeatedly, though! They were starting/stopping because the power would come back on for up to 2-3 minutes before going back out - they'd finish their cool down period only to have to fire back up again. They're decent sized units that handle elevators and emergency lighting, plus some refrigeration. Some are natural gas, some are diesel, depending on the building. I don't think they're configured to stay on after a certain number of outages, at least not the ones I was near at the time.
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Apr 20, 2012 19:44
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alwayslost posted:I'm a junior EE student and I recently got an internship at the local utility. The job is kind of lame (analyzing large amounts of data for improving substation performance) but hopefully it will be my foot in the door to getting a design-type job. My internship last year was in integrated circuit design, so I'm kind of all over the map right now. What is the market like for power engineers right now (my full-time job hunt starts this fall)? It seems to me like a solid industry to get into in the United States, since energy is a hot thing right now and you can't really outsource our utilities. The semiconductor industry, on the other hand, seems like a sinking ship in the United Stats, where only the super elite can find jobs with the titans like Intel, Texas Instruments, Qualcomm, etc. Power engineering is a very good field. Between updating the existing infrastructure, adding capacity for the ever increasing demand for more power and implementing new technologies, there is more work than the existing workforce can handle. Getting a MSEE is a good idea, especially if your employer will pay for it.
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Apr 20, 2012 19:57
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A good % of power engineering jobs are inherently local in nature, and very unlikely to ever be outsourced. I'm not so sure of the advantages of an MS, though. A BS plus 2 years work experience would probably serve you better than an MS.
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Apr 20, 2012 20:03
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coffeetable posted:Electrical porn: one of ITER's (the fusion project going on in the south of France) press releases this morning was on the their switchyard. Plus a technical presentation if you're so inclined. 400kV supply, 500MW pulsed draw and a short circuit power of 10GVA How many feet of concrete is appropriate arc-flash protection for 10 GVA?
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Apr 21, 2012 03:52
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Frozen Horse posted:How many feet of concrete is appropriate arc-flash protection for 10 GVA? Depends on how many fractions of a cycle it is. I need to see if PowerTools will allow a utility fault (line to line) of more than 1GVA. If you're a big customer that has your own substation at a voltage greater than medium, I could see faults over 1GVA being possible. It's hard to comprehend the power of faults even in the hundreds of MVA range. This snippet of a book on Google indicated that on one of the UK's 400kV distribution systems, the maximum fault level was... 37GVA.  For those browsing through this thread and have no idea what this is like, the monitor in front of you probably consumes somewhere between, say, 20 and 150 VA. For a very short duration, a fault on that line mentioned was 37,000,000,000 VA. Three-Phase fucked around with this message at 04:34 on Apr 21, 2012 |
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Apr 21, 2012 04:24
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Oops. IEEE said that Hydro Quebec's 765kV system's maximum fault level is 53GVA.
Three-Phase fucked around with this message at 04:39 on Apr 21, 2012 |
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Apr 21, 2012 04:37
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Three-Phase posted:53GVA.
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Apr 21, 2012 16:30
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According to Wikipedia (http://en.wikipedia.org/wiki/Hydro-Qu%C3%A9bec%27s_electricity_transmission_system) it's AC, but I thought it was DC until I checked, so... I don't know poo poo. (Turns out the DC like is a 450 kV line going to New England; the more you know.)
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Apr 21, 2012 23:59
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Those are some big transformers. I've been around 50+MVA transformers where you have the big firewalls between each transformer. Wow, check this out: 1100kV (1.1MV) substation in Japan. I'm amazed at how well SF6 insulates. Three-Phase fucked around with this message at 03:27 on Apr 22, 2012 |
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Apr 22, 2012 03:22
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How is that even possible without everything exploding?
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Apr 22, 2012 08:06
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Ender.uNF posted:How is that even possible without everything exploding? It's also non-toxic, doesn't burn, and conducts heat well. It's all-around great for high voltage components. grover fucked around with this message at 14:05 on Apr 22, 2012 |
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Apr 22, 2012 14:01
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And if you breath it in it has the opposite effect of helium.
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Apr 22, 2012 15:13
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helno posted:And if you breath it in it has the opposite effect of helium. On Mythbusters: http://www.youtube.com/watch?v=d-XbjFn3aqE
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Apr 22, 2012 16:54
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I was trying to understand that fusion presentation, and correct me if I'm wrong, but it was showing an output of 5x10_8MW at peak? As in, 50 million megawatts?
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Apr 23, 2012 04:44
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MA-Horus posted:I was trying to understand that fusion presentation, and correct me if I'm wrong, but it was showing an output of 5x10_8MW at peak? Screwup with the axis labelling I suspect. 5x10^8W = 500MW.
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Apr 23, 2012 17:27
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MA-Horus posted:I was trying to understand that fusion presentation, and correct me if I'm wrong, but it was showing an output of 5x10_8MW at peak? Well, it is fusion. Maybe for a fraction of a microsecond?
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May 5, 2012 01:12
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I believe it's the power input, and 500MW Peak is also what it says in the introduction so yeah the labels are screwed up. Take a look at the chart on page 17, it settles into a nice steady 300MW consumption for 7-10 minutes at a time.
shame on an IGA fucked around with this message at 02:20 on May 5, 2012 |
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May 5, 2012 02:17
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The Proc posted:I believe it's the power input, and 500MW Peak is also what it says in the introduction so yeah the labels are screwed up. Take a look at the chart on page 17, it settles into a nice steady 300MW consumption for 7-10 minutes at a time. Oh, duh. 300MW is somewhat impressive. (On par with something like a steel mill.) If my math is right that's a nominal current of 433A at 400kV, assuming unity power factor of course. I thought that would be maybe 350kcmil. The NEC only goes up to 35kV, and that's for insulated wires. Did a little research. For most low-voltage applications, you use 60C as the teperature of the conductor. Medium voltage it goes up to I think 105 or 115C. For the overhead lines I saw, the ampacity was at 200C (with 25C ambinet temperature, and some specifications for sunlight and wind). So you could easily feed that whole thing with 266kcmil aluminum "Partridge" wires. I didn't see ampacities lower than about 800A. (I'd check the presentation but Firefox just poo poo itself.)
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May 5, 2012 04:58
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