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AmbassadorTaxicab posted:How are brownouts managed, in the context of load-shedding? Ontario had one a number of years ago, and this was the reason given. Breakers with undervoltage relays are often designed to automatically reclose when proper voltage is restored, which could lead to a vicious cycle in a brownout. Power companies will very often cut deals with large customers that have emergency generators, where the customer is charged a lower power rate in exchange for agreeing to voluntarily take themselves off the grid during brownout conditions. Which is generally a win-win, as that sort of customer would be taking themselves voluntarily off the grid anyhow in brownout conditions to avoid damage or risk of power interruption. e: This can occur even at the residential level. Anyone who's used a large power tool at the end of too many extension cords has noticed how easy it is to stall the tool; this is because voltage drop on the extension cord leads to very low voltages. Stalled motors are essentially short circuits, and can cause the breaker in the house to trip. In brownout conditions, this can lead to motors in air conditioning units and refrigerators tripping breakers, taking those loads off the grid. grover fucked around with this message at 16:52 on Aug 9, 2013 |
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Aug 9, 2013 16:30
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White House calls for increased spending on the electircal grid: http://hosted.ap.org/dynamic/stories/U/US_OBAMA_ELECTRIC_GRID?SITE=AP&SECTION=HOME&TEMPLATE=DEFAULT Where should the spending be targeted? Is it a matter of like-for-like replacement of old poo poo, adding capacity, or something else?
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Aug 13, 2013 17:48
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IMO hardening it against EMPs/solar storms would be a good start. And making it more failure resistant in general. And maybe stocking more spare parts. A solar storm of the Carrington Event scale would leave us completely dead in the water as a society unless we saw it coming (completely possible, we usually get a half day to 3-4 days notice) and then shut the entire grid down and disconnected everything to weather the storm (very unlikely.) The worst part? If it fried some parts, it'd be years before we had everything back again. IIRC most very large substation transformers aren't stocked anywhere due to their cost, they're made to order and it takes a long time even if you didn't just get blasted with a few bajillion tons of electrically charged solar splooge.
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Aug 14, 2013 21:36
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kastein posted:solar splooge. I wish I had the  for a username change.
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Aug 14, 2013 22:15
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I figure this would be the place to ask. Every day I walk past the pole in the image and I've always wondered what its for. It just seems like a bunch of wires that are waiting to be hooked up to a circuit but its been this way for years. Wouldn't those normally be wrapped up and protected from the elements? Its the pole in the middle with the candelabra arrangement of wires on it, not the transmission lines in the foreground. This is in an industrial park in Montreal, Canada. Sorry about the crap quality, cell phone...
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Aug 14, 2013 23:49
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Maybe it was abandoned in place like that? There used to be pole transformers up there that were removed and the rest was abandoned?
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Aug 15, 2013 01:19
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That would make sense. It is an industrial park so businesses are coming and going all the time. A little unusual to see Hydro-Quebec just abandon their stuff though.
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Aug 15, 2013 01:46
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So I was goofing off on google maps when I found this : http://goo.gl/maps/4GyiQ I've never seen a power plant that small or set up like that so I was hoping someone in this thread had any info on an installation like this.
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Aug 19, 2013 02:04
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Exploding Barrel posted:So I was goofing off on google maps when I found this : http://goo.gl/maps/4GyiQ That's indeed really small, and I don't see any lines heading out 
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Aug 19, 2013 02:10
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Exploding Barrel posted:I've never seen a power plant that small or set up like that so I was hoping someone in this thread had any info on an installation like this. http://www.tva.com/power/cumb_turbineart.htm They are usually used for supplying electricity during periods of peak demand. They are expensive to run, but can be started or shutdown quickly to accommodate changes in grid loading.
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Aug 19, 2013 02:20
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You can see the lines going out north-north east. From each generator you can see three sets of phase-isolated bus ducts (look like, well, ducts) going into a step-up transformer. If you want to see a tiny nuclear plant, look for Davis Bessie. It's the cutest little power plant you've ever seen. On the other scale, the property for the Chernobyl nuclear power plant is absolutely enormous. Three-Phase fucked around with this message at 02:44 on Aug 19, 2013 |
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Aug 19, 2013 02:40
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Three-Phase posted:You can see the lines going out north-north east. From each generator you can see three sets of phase-isolated bus ducts (look like, well, ducts) going into a step-up transformer. It's adorable and apparently riddled with problems. Thanks for the into on the peaker plant, never seen one before but it makes a lot of sense as the main power plant for the area is about 36 miles north of it.
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Aug 19, 2013 02:52
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Gisnep posted:That's a combustion turbine plant. That particular plant is owned by Reliant Energy, but I cannot find any info about it, specifically. Many (particularly older) combustion turbines are the same model as you find on ships, which are in turn, mostly derived from aircraft engines. My father currently works on FT12s, which are the fixed version of the Pratt and Whitney JT8. When I was a kid, though, he worked on GG4/FT4s, which are the fixed versions of the J75/JT4. That was at this place. He worked at the steam plant there, mostly, but did a couple of years at the GTs, off and on through the years.
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Aug 21, 2013 13:28
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Alright, weird question. Are DIN rail circuit breakers standardized at all? We've got some Altech 2Z30UM dual pole 30A Z-trip breakers we need to add a shunt trip to. Can't find Altech shunt trips in stock anywhere, but the electrician found another brand's shunt trips. Just not sure they'll bolt to the other breakers, my suspicion is that they won't, unless 35mm tophat DIN rail circuit breakers are standardized enough that the trip mechanism for ganging breakers is always the same shape and in the same place.
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Aug 21, 2013 19:21
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kastein posted:Alright, weird question. Are DIN rail circuit breakers standardized at all? We've got some Altech 2Z30UM dual pole 30A Z-trip breakers we need to add a shunt trip to. Can't find Altech shunt trips in stock anywhere, but the electrician found another brand's shunt trips. Just not sure they'll bolt to the other breakers, my suspicion is that they won't, unless 35mm tophat DIN rail circuit breakers are standardized enough that the trip mechanism for ganging breakers is always the same shape and in the same place. I really doubt it, and I wouldn't risk experimenting on them.
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Aug 21, 2013 23:14
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Well i didn't notice this until today Photonic Induction's killer screwdriver. I know they had blown-fuse indicators that worked that way, but not testers that would run a few microamps through a person.   
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Sep 8, 2013 22:43
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That guy has simultaneously the best and the worst accent for doing that sort of thing. So are those just screwdrivers that let you screw stuff with low(ish) voltage running though them?
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Sep 9, 2013 03:21
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I think the idea is that it lights up if you touch a live terminal. I'll stick with a conventional pot tester thank you very much.
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Sep 9, 2013 03:30
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Pass.
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Sep 9, 2013 18:37
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dupersaurus posted:That guy has simultaneously the best and the worst accent for doing that sort of thing. They're just testers to see if a wire/terminal is live. Very handy, and could even be safer than trying to fumble around with two leads. The neon tube limits current to a very small, very safe value.
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Sep 9, 2013 19:44
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Why not just use electric field decetors, I mean touching a live or potentially live circut above 30v is potentially a death sentence, and a 120v and over would just be idiocy!
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Sep 9, 2013 21:53
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AmbassadorTaxicab posted:They're just testers to see if a wire/terminal is live. Very handy, and could even be safer than trying to fumble around with two leads. The neon tube limits current to a very small, very safe value. Given that the idea seems to be "we only need one point of contact because it'll flow to ground through whoever's holding the other end", I personally think the whole concept is functionally retarded. I mean if that's what you really wanted you could use a conventional two-point tester and just hold the second lead in your mouth, and I'm pretty sure nobody thinks that's somehow a good idea. Jabor fucked around with this message at 09:32 on Sep 10, 2013 |
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Sep 10, 2013 09:26
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Ryand-Smith posted:Why not just use electric field decetors, I mean touching a live or potentially live circut above 30v is potentially a death sentence, and a 120v and over would just be idiocy! Those are great and do save lives. The only issue is if you're working at a place that has heavy industrial electrical systems or with a power company that has electrical distribution equipment, you may see a lot of 120VDC control power. That can hurt you but the Fluke VoltAlert won't be set off by that. I'm starting to add additional, specific warning labels for equipment that has >28V DC control power inside it instead of a more standard "This equipment is fed from multiple sources of power."
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Sep 10, 2013 11:15
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I don't really know if this is the right place to post this but I chose not to buy a Fluke multimeter because $100 and instead got a cheap Klein tools multimeter, and it's loving poo poo. It takes over a second to even begin to display results and the continuity beep test is so quiet I can't hear it in my working environment. Tried to save 60 bucks and it's wound up costing me an extra 40 because I'll have to buy the Fluke after all.
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Sep 13, 2013 06:48
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Three-Phase posted:Those are great and do save lives. We started putting florescent red adhesive strips next to the entry terminal board for any external sources of power. Mainline, Standby, Control. The only exception is the florescent green we use for <28VDC which is only ever used for indicator lights. Everything has a sharpie pen in for the designator of whatever source that is. We're working on getting nice professional label plates made for everything which has a full in depth list of every source. Gotta have that aesthetics before anyone will approve any alternations. Granted, the tape alone is unapproved. But out of sight out of mind and all that.
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Sep 13, 2013 10:42
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Two Finger posted:I don't really know if this is the right place to post this but I chose not to buy a Fluke multimeter because $100 and instead got a cheap Klein tools multimeter, and it's loving poo poo. It takes over a second to even begin to display results and the continuity beep test is so quiet I can't hear it in my working environment. Klein makes top-end hand tools, but beyond, that... yeah.
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Sep 13, 2013 13:15
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Two Finger posted:I don't really know if this is the right place to post this but I chose not to buy a Fluke multimeter because $100 and instead got a cheap Klein tools multimeter, and it's loving poo poo. It takes over a second to even begin to display results and the continuity beep test is so quiet I can't hear it in my working environment. I use these types of devices for data infrastructure rather than power, but yeah...what were you expecting? I still have an ancient yellow fluke and it works great to this day. Spend the extra coin.
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Sep 13, 2013 16:24
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M_Gargantua posted:We started putting florescent red adhesive strips next to the entry terminal board for any external sources of power. Mainline, Standby, Control. The only exception is the florescent green we use for <28VDC which is only ever used for indicator lights. Everything has a sharpie pen in for the designator of whatever source that is. We're working on getting nice professional label plates made for everything which has a full in depth list of every source. Gotta have that aesthetics before anyone will approve any alternations. Granted, the tape alone is unapproved. But out of sight out of mind and all that. I use label maker tape, it's ghetto but this is a house not an industrial installation (hahaha, for now! Until I pour a cement floor in the basement and begin filling it with as many machine tools as I can get my hands on) so it's not even required.
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Sep 13, 2013 17:13
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Three-Phase posted:Well i didn't notice this until today Photonic Induction's killer screwdriver. Those are insanely common in the developing world; all the electricians I worked with in India and China had one. Since most of our plants use 24vdc or 120vac control power, it made a reasonable amount of sense, since it wouldn't electrocute you even when accidentally used on 240VAC. If you magically poke it into 4160V, I'd assume it'll hurt (if briefly), but I've seen them used up to 240V with no ill effects (not that you'd catch me trying it). They're largely banned (by law or regulation) in 1st world countries; the Aussie jobsite I was at threatened to kick a guy offsite for having one. Apparently the bulb can fall off the contacts, leaving the user as the line->ground resistor.
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Sep 13, 2013 17:17
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M_Gargantua posted:We started putting florescent red adhesive strips next to the entry terminal board for any external sources of power. Mainline, Standby, Control. The only exception is the florescent green we use for <28VDC which is only ever used for indicator lights. Everything has a sharpie pen in for the designator of whatever source that is. We're working on getting nice professional label plates made for everything which has a full in depth list of every source. Gotta have that aesthetics before anyone will approve any alternations. Granted, the tape alone is unapproved. But out of sight out of mind and all that. I was at a plant in Ohio where they had a florescent orange label on each cabinet detailing the incoming power sources (voltage, current capability, arc flash hazard, and a lockout point) on every cabinet. Struck me as a decent idea, but nobody else seems to want to implement it.
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Sep 13, 2013 17:20
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TyroneGoldstein posted:I use these types of devices for data infrastructure rather than power, but yeah...what were you expecting? KaiserBen posted:I was at a plant in Ohio where they had a florescent orange label on each cabinet detailing the incoming power sources (voltage, current capability, arc flash hazard, and a lockout point) on every cabinet. Struck me as a decent idea, but nobody else seems to want to implement it.  It's legally required now. Well, most of that at least. "Nobody else" really don't have much choice in the matter.grover fucked around with this message at 17:31 on Sep 13, 2013 |
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Sep 13, 2013 17:28
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grover posted:I'm a big fan of Extech. Every Extech meter I've used has been every bit as good as a Fluke, but without the Fluke tax attached. If it is, I can name at least 10 major plants in the US that are out of compliance. Arc flash data is, but lockout points aren't (at least that I can find in the code books).
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Sep 13, 2013 17:39
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I have an Ideal 61-704 I absolutely love. Everyone kind of looks at me funny when I say that but I use it almost every day and I've never had a bit of trouble. I take that back.....the case is a complete piece of poo poo but the meter is great.
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Sep 13, 2013 22:32
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M_Gargantua posted:We started putting florescent red adhesive strips next to the entry terminal board for any external sources of power. Mainline, Standby, Control. The only exception is the florescent green we use for <28VDC which is only ever used for indicator lights. Everything has a sharpie pen in for the designator of whatever source that is. We're working on getting nice professional label plates made for everything which has a full in depth list of every source. Gotta have that aesthetics before anyone will approve any alternations. Granted, the tape alone is unapproved. But out of sight out of mind and all that. I like that! Trust me, if you're working at a medium-sized facility, or even doing commercial stuff, get a labeler of some sort. Nothing is worse than digging through a set of terminals and not knowing what the hell is what. Also, if you're in the cabinet, you can use a single number to identify one wire from another. If that wire goes out of the cabinet, please have a more detailed label showing at the very least what cabinet/terminal strip the wire is going to. You can also use a wire label that is made for two-lines on much larger cables, and wrap it around sticking the sticky part to the sticky part and make a little "flag" if you need to add more information to a wire. Does Extech have a good process calibrator like the Fluke 726? Something that can do milliamp loops down to microamp precision? Three-Phase fucked around with this message at 23:24 on Sep 13, 2013 |
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Sep 13, 2013 23:17
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Three-Phase posted:Does Extech have a good process calibrator like the Fluke 726? Something that can do milliamp loops down to microamp precision? Quick google search shows Extech has a pretty good range of calibrators; looks like their process calibrator also goes down to 1μA precision. For about 1/8th the price of a 726. http://www.extech.com/instruments/categories.asp?catid=3 If I was doing something where I absolutely needed accuracy to 1μA... I think I'd pay the extra 3 grand for the Fluke, though. Just for the CYA factor of having used a "fluke". grover fucked around with this message at 00:42 on Sep 14, 2013 |
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Sep 14, 2013 00:39
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Speaking of Fluke, anyone have any recommendations for a decent all-around model for working in low voltage control panels? One of the sister companies of the place I work for carries Fluke, and I'm told we can buy them at cost for ourselves. All I have at home is a cheap Craftsman POS, so I'd like to upgrade to something decent for personal use. Primarily to take out to the field, because the general use meter for engineers is a POS so we usually have to beg one from a technician when we go out on site. What I'd really love is something that can do clamp-on 4-20mA measurement, but I'm sure that's an expensive accessory or separate unit. I'd need to measure 4-20mA somehow at the least.
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Sep 15, 2013 05:38
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Three-Phase posted:I like that! Don PPE, open it up, check everything that's colored. Simple. Even had a two party verification to make sure we didn't miss anything or mislabel at all. DaveSauce posted:Speaking of Fluke, anyone have any recommendations for a decent all-around model for working in low voltage control panels? I have a personal love of the 289. Every feature I've ever needed.
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Sep 15, 2013 11:13
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DaveSauce posted:What I'd really love is something that can do clamp-on 4-20mA measurement, but I'm sure that's an expensive accessory or separate unit. I'd need to measure 4-20mA somehow at the least. http://www.amprobe.com/amprobe/usen/Clamp-Meters/Specialty---Leakage,-Recording,-Analog/AC50A.htm?PID=73058 
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Sep 15, 2013 14:21
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grover posted:Works pretty good on AC; not sure how it would be on DC controls.
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Sep 17, 2013 13:44
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I made that mistake once and got poo poo for at least two years. Rightfully, too.
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Sep 17, 2013 20:20
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