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Tuesday, December 29, 2009

Monday, December 28, 2009

How to Capture and Visualize 60Hz

Boring electrical geek ramble here.

100 years ago, many AC systems were operated at 25Hz (25 cycles per second), and pretty much anyone could detect it when looking at a light bulb. You could see it pulsing really fast. At today's 60Hz, it is pretty much impossible to detect that pulse in an incandescent light bulb, because the filament does not have enough time to noticeably dim between the 60-times-per-second pulses.

Unlike incandescents, fluorescent lights visibly pulse to some people whose eyes are sensitive enough. Like mine. I can see the flicker of computer monitors set to 60Hz, too. Both give me headaches. Many monitors have configurable frequency settings, so I change them to as high a setting as possible. If I can't, the monitor is disposed of.... somehow I usually find a way. And of course I avoid using fluorescent lights as much as possible.

But there's a relatively new flicker-detectable 60Hz light source out there, and I probably can't run away from it:  Cheap LED lights.

LEDs are either ON or OFF. There is no 'warmup' or 'cooldown' interval.

Have you ever seen one of those spinning light gadgets sold at gift stores, with the LEDs on it? As they spin, the lights make various multi-colored solid lines or dashes or dots, rotating back or forward, and they are fabulous for mesmerizing cranky 2-year-olds for a few minutes.

Next time you get your hands on one of those, grab the spinner so it can't turn, and then turn the thing on. These are battery-operated, so they are not strictly 60Hz, but run at variable frequencies controlled by the internal circuitry. You'll note that, when the spinner is not spinning, the LEDs are constantly changing in their intensity. Brighter, dimmer, to varying degrees. What you are seeing is the pulse rate affecting how much total light they give off. When the LEDs are stationary, your eyes detect the difference in total light delivered as brightness, but when spinning you can see the actual pulses as the dark gaps between the lines and dots in its rotation. Cool, huh?

So there's a lot of Christmas lights that are LEDs now, and I can tell them from the old ones instantly by their flicker. I was at a big Christmas light display with hundreds of thousands of these LED lights, and I about went nuts. Since these are AC, they always pulse at 60Hz. How to visualize that when they don't spin? I used my cell phone camera, and swung my arm quickly sideways while taking a picture of the lights. Can't rotate the lights, then rotate yourself. The result is below.

There's lots of reds in there, but only a few blues or greens. Count the number of blue dots captured from one of these lights, and you'll see that my cell phone camera captured six pulses. At 60 pulses per second, that means my camera caught 1/10th of the pulses delivered every second.... so now I know that my cell phone camera's exposure time is 1/10th of a second. Incidentally, there are a couple of white incandescents that got caught in there on the lower left, and you can see the intensity of one of them oscillating, though it never has enough time to go out between pulses, hence the pulses are invisible to the normal naked eye.

Cool huh?

Or boring.

I know it's late, but Merry Christmas!

Friday, December 25, 2009

The Pre-Plan

Showed up for work at the power company this fine Christmas morning.

Keeping the lights and the heat on for you while you do whatever you do this holiday. Don't mention it. I get paid extra to be here and I am happy to have a job.

Anyway, for some reason, the refrigerator was replaced during my days off. Looks like the person in charge ordered a really nice stainless steel side-by-side to replace the old one. What was wrong with the old white enamel one is not clear. Apparently the boss simply wanted us to have a new one. With stainless steel.

They didn't go cheap. Bought a side-by-side to replace the old over/under. After all, we're a multi-billion $$$ company, so we can afford it.

If you've never compared refrigerators... typical mid-line over/unders are about 33" wide, while side-by-sides are rarely (if ever) less than 38" wide.

Yeah, you can see where this is going.

So in the corner of the control center kitchen, where the old fridge used to be, the new one is in front of the old hole, turned 90 degrees and against the side wall. Now we have the loss of space in the kitchen, the open and inaccessible hole blocked by the sideways fridge in front of it which will no doubt gather accidental trash and crud, and you know..... the new one has less fridge space than the old one overall, in exchange for a bigger freezer that we pretty much never use.

Not to mention, the all-important pizza box doesn't fit in a side-by-side.

Nice upgrade.

Pre-plan FAIL.

I'll keep you posted on what comes next: (A) Swap for smaller fridge (with or without consulting the guys who actually use it), (B) Spend a bundle to remodel a kitchen that does not need a remodel so that the wrong fridge will now fit, or (C) just leave the goofy situation as is.

Saturday, December 19, 2009

Fuzzy Brain Radio Follies

Engine 51, Engine 57, Mayberry Engine 13, Medic 98.... traffic accident.... tac channel is TAC2.

Ugh. Engine 51 is first-due. I look at the clock. 02:24. Ugh. OK, here we go.

The fuzz is heavy. I pull out in trusty 51 and grab the mic to come online.

Engine 51 is responding.

10-4 Engine 51.

I then hear a couple of other sort-of-nearby units from our agency start our way, ready to turn around if not needed.

Then I look at the radio. Oops... I used the FireMed channel.... but they answered me anyway and just went with it, without a poke. Thanks, guys.

I pick up the mic again to advise dispatch that I am cutting over to Mayberry's response channel to touch base with Engine 13 when they come up. You see, they don't have the fancy-schmancy 800MHz system we have, so on M/A someone has to go meet them on their channel.

As I key the mic, I abruptly realize that I never changed channels in the first place. I am still on FireMed instead of TAC2. Since I came online first, as first-due I am the one responsible to initiate the correction and make sure everyone is moved over to TAC2.

I have two messages in my fuzzy head, and I have already keyed the mic. (#1) I am going over to Mayberry Channel 4 for a moment. (#2) Let's move all responding units to TAC2.

My fuzzy brain, under pressure (mic is keyed), smashes these two messages violently together.

Dispatch from Engine 51, let's move all responding units to Mayberry Channel 4.

Oh crap, did I really just say that on the air?

I really fubar'd this. I can visualize every guy on a responding unit, as well as anyone else listening, staring at their radios as if they just channeled radio traffic from the Burger King drive-thru. Say what? You want us to... did he just say that?? Not all units responding even have the capability to go to Mayberry's channel.

And I'll be danged if the dispatcher didn't just go with that, too, nary skipping a beat.

10-4 Engine 51. All units responding on the traffic accident, move to Mayberry Channel 4 per Engine 51.

I wish he had put the brakes on and called me on the goof... but off we go before I can pipe up again to fix it.

So... some guys just follow orders and go to Mayberry Channel 4 as directed, some stay on FireMed to see what my next move is because they realize I am fuzzed up and should come out of it soon, while still others go to TAC2 as we were supposed to have done all along. Once I let the livestock out of the pasture, I wasn't sure how to get them corralled again. From there on out, it was a great big communications Charlie Foxtrot.

Thankfully it was a one-car, non-injury wreck, not a lot of coordination involved in finding units, whichever channel they went to, and telling them to cancel.

Lesson to self (and I rant about this to the new guys constantly): Engage brain and think over your message before you key the mic.

The Captain sat me in the office for a few minutes the next day, just to make sure I still knew the protocol for M/A and TAC channels. He knows it was 0-dark-30, but he had to check. I don't blame him.


Tuesday, December 15, 2009

Commentary on Death by Ignorance, and System Protection

There's a little tie-in commentary I want to make in regard to the previous post and all of the system protection stuff talked about in the last two tutorials.

Everything in a substation is protected by zones, so why in the world would the carnage depicted in the photos on the last post be so severe? Why didn't something detect the fault and clear it before it got so bad?

Well, my friends, what probably happened in that case and does happen in many others like it, is that technically there was never a fault. There was never a hard connection to the fatal arc from the generator-to-component chain that is watched by fuses and relays.

Part of the transmission of electricity involves a powerful electromagnetic field which literally rotates around energized equipment and power lines, out to a distance of several yards, though the strength of this field weakens quickly as the distance from the energized equipment increases.

You hear about people complaining about EMF exposure when living near power lines, so you can imagine the distances the fields can reach out to. And then you can imagine the fields you're immersed in when you're in a substation and fairly close to the big stuff. Induction potential is normally negated on the structures and fences at stations by the grounding straps which dissipate the potential immediately

If the induction potential is not dissipated by grounds (because some Darwin Award candidate removed them), any electromagnetic induction potential will look for a way out, and will create an arc when it finds it. Since it draws no actual fault current from the energized equipment, there is nothing for the relays to detect. It will just burn and burn and burn, either until (1) there's nothing left to burn, (2) the damage created by the arc grows so large that the arc can no longer jump the gap, (3) the arc reaches energized equipment where the relays can see it, (4) the damage causes a structural failure of some variety that indirectly creates a real fault, or (5) a power company guy observes the arc and takes action to de-energize the associated equipment.

So, as you might conclude, exposure to electricity by induction is far more hazardous than exposure to straight-up energized equipment. The energized stuff will pretty much kill you 99.999% of the time, though rare exceptions have been noted and made possible by quick fault clearing and only on relatively low voltages. But you've got no chance at all when you get whacked by undetectable and non-clearing induction current.

Just some things to think about.

Friday, December 11, 2009

Death by Electricity and Ignorance

The Smooth Substation Operator sent these to me recently.

Be clearly warned: The photos behind these obfuscated thumbnails are full color, full detail, are not for the faint of heart, and are every bit as visually traumatic as the appearance of victims of fire. 

I do not know where this took place, how long ago, or who these souls were. They attempted to steal electrical cable to trade for cash at a scrap dealer, for reasons I won't guess on, as it is no longer important to them or us.

It is fairly common for power companies to have the neutral grounding straps cut and removed from substation structures and facilities by metal thieves. Disconnecting the neutrals can allow voltage induction, with no way for the stray potential to be grounded and made harmless. In some cases, the removal of grounding straps might give you a buzz when touching something normally "safe", but in other cases without the grounds, touching something normally as innocuous as the station fence can be fatal. Always look for intact grounding straps attached to the fence before you touch it. Or... just don't touch.

Anyway, I digress. I am willing to bet that if you asked these two before they got into it, if what they wanted the cable for was worth risking their lives, they likely would have said no.

As such, they did not know what they were dealing with, gambled in a game where they didn't understand the stakes, and lost. These aren't the first guys to die doing this, and won't be the last.

Now you know what you're dealing with. Stay away.

Again, the full-size photos are uncensored, visually graphic, and may be upsetting to some of my readers. If in doubt, just don't open them. Some things are hard to forget, you know.

Wednesday, December 9, 2009

Not grid. Not fire. But, dude.....seriously?

My previous post, Mobile Command Post Fail so far brought in just one comment.

But it was a good one.

Learned about a new site. No idea why I had not heard of it before, because it is my kind of funny.

But seriously, you want a REAL mobile command post? With style? It's even red:

You just gotta go see the rest of the pics. Don't miss the interior driver's seat picture. Holy crap!

Wander around Hamsexy a bit. You'll laugh, you'll cry, you'll basically never get those ten minutes back and you'll wish you had gone your whole life without seeing some of that stuff.

Thanks, Jacob.

Tuesday, December 8, 2009

Mobile Command Post Fail

How many antennas are enough? How many more are required to impress the ladies? How many more to impress the ladies enough that they'll overlook the rust?

But you're a ham radio guy? Yeah, so am I. And you're a card-carrying storm spotter/chaser? Yeah, so am I, though I loathe the punks who drive like hell just to watch carnage under the spotter pretext. I work with the kinds of guys who actually report data to the NWS and, you know, get tornado sirens activated to, you know... try to save lives. I don't even bring a camera with me. Anyway, I don't have that many antennas (just the one is fine, thanks), and can still do everything I need to do despite not having 'Skywarn' stickers nor whackerbar lights for 360 coverage. But hey, I bet you get more dates than me.

Monday, December 7, 2009

Tutorial 9: System Protection, Part II

After a long layover, the tutorial is back.
I hope you enjoyed the break.

A quick total review of what we have learned so far:

In Tutorial 1 - DC vs. AC, we learned... well, the difference between Direct Current (DC) and Alternating Current (AC) and why AC is used for the grid.

In Tutorial 2 - AC Supply and Demand we learned that power on the AC grid is produced exactly at the rate it is consumed, and that it cannot be stored.

In Tutorial 3 - Generation Supply, Control and Scheduling we learned how power companies decide which power plants to run, and how they exchange power between companies.

In Tutorial 4: Basic ACE, and Reserve Sharing we learned how power companies determine if they are generating too much or not enough power, and how they quickly recover from the loss of a big power plant with help from their neighbors.

In Tutorial 5: Introduction to Power Lines we learned about the different types of lines and voltages are used to move power efficiently, and about transformers.

In Tutorial 6: Identifying the Wires and Tutorial 7: Identifying The Wires, Part II we learned how to... well, identify the wires.

And lastly, in Tutorial 8: Introduction to System Protection we learned why the system protects itself.

Wow, that rehash was long enough to be its own blog post. But it's been over a month since we did one of these, so I feared you might be rusty.

Well, I am, anyway.

Seriously, you might want to at least re-read Tutorial 8 to spin things up again before starting this one.

And you are hereby forwarned, this will be a LONG post. Go refill your coffee now and stop in the restroom on the way. We'll see you in a minute or two.


OK, ready?

The electrical grid is protected at every point on its journey from the power plant's armature windings to the end terminals of the power cord inside of Firegeezer's coffee pot. For most of us, this power travels a pretty long distance, goes through several voltage changes up and down, passes through switches and circuit breakers, and does a few other exciting things before getting to you. It is not practical to dump the entire grid between you and the power plant if your coffee pot shorts out, so your household circuit breaker does the job. That action defines the first of many segments, or 'zones of protection' in power company parlance, the first (or last) of which is the zone between your breaker panel and your coffee pot, protected by your panel breaker.

An aside on circuit breakers. On this blog I pretty much always refer to the large breakers generally found in substations. These breakers have just one job: break the circuit. They cannot sense problems, so they only open when commanded to by other equipment. I might get into those big breakers later, but I want to differentiate the big breakers from the tiny breakers found on the breaker panel in your home. Your tiny breakers do both jobs; that is, they detect the problem AND break the circuit. Tiny breakers detect problems in two ways: The electromagnetic portion detects sudden surges, and the bi-metal portion detects high loads over time. Look it up if you want to know more about those, just so you know that aside from the size difference, there is also a functional difference between the big breakers and the tiny household ones.

Back to the zones.

The names I will use below I am more or less making up to keep things simple for the uninitiated, and may or may not be the terms used locally by your power company. In fact, they probably aren't. If you try to mention these specific zone names to linemen, other dispatchers or protection engineers, they will probably look at you with a raised eyebrow and try to tactfully change the subject.

So, the first zone we have identified. We'll call it the COMPONENT ZONE, referring to components that you plug into your outlets at home. The elements protected are, going backwards: Coffee pot, power cord, electrical outlet, wiring in your wall leading from your breaker panel to that outlet. If there is a problem here, as long as things are installed properly, your household circuit breaker should take care of it.

The next zone is relatively tiny, the PANEL ZONE, and pretty much just watches the stuff inside your breaker panel, between the main breaker and the individual circuit breakers. If something goes awry in the panel, the main breaker will dump the house. Also, if one of the circuits in your home in the COMPONENT ZONE has a serious problem and the assigned circuit breaker fails to clear it in a timely manner, and if things are configured properly, the main breaker should dump the panel to take care of business.

The next segment is the SERVICE DROP ZONE. This starts at your main breaker and goes upstream from there, to the source wires going through your wall and to the service drop or other point of entry, out via overhead or underground service wires to wherever your local service transformer is, be it a pad mount transformer or a poletop can transformer, and then up to the fused cutout serving the transformer. The fused cutout was touched on in the "Wires" tutorials, it is a switch where the opening part is also a large fuse. If something happens downstream from this cutout that draws enough load, the fuse will blow. It generally will blow for problems with the transformer, but if there is a problem downstream from that drawing a lot of fault current and not being cleared, it will eventually cook the transformer and cause the fuse to blow. Sadly, by the time the cutout blows for a problem at your panel or somewhere downstream that was not handled by the main breaker, your house is on fire already, causing me to drop what I'm doing and come see you in my Big Red Truck anyway. See, I'm involved either way.

The next segment is the FEEDER ZONE, which travels upstream from your cutout switch. That includes the jumper or other tap wire from the cutout to the primary distribution feeder conductor, and that feeder circuit back to the next breaking point. For most applications, that breaking point is a relatively small substation feeder breaker. Alternatively, there may be an in-line field recloser (basically a light-duty feeder breaker mounted on a pole) or other switch designed to sectionalize the feeder into pieces. Sectionalizing makes sense for long feeders or multi-branched feeders. If you can detect a problem and isolate just the troubled portion while still reaching the rest, it makes it unnecessary to dump the entire feeder. These breakers and reclosers cannot generally detect problems on their own, but rely on signals from other equipment, known as relays, which measure things like voltage, amps, flow magnitudes and such, for Bad Things. When Bad Things happen, the relay will then tell the appropriate device(s) to open. The relays at this point may take up to several seconds to decide there is a problem and clear the circuit. Also, the relays are often set up to attempt to reclose the breaker once or twice to see if the problem was transient (we talked about that in past posts), but will give up after enough failed attempts.

The FEEDER ZONE segment backs up the fused cutouts if they don't blow and draw enough fault current, but this backup is not very reliable. It is impractical to reliably get the relays to sense that kind of small fault that far away.

This picture placed here to give you some brief unrelated entertainment, because this post contains no other photos. Entertained adequately? Good.

The next segment is the DISTRIBUTION BUS ZONE, and is a small area running from the circuit breaker at your distribution station into the bus work at that station, which serves all of the other feeders. Typically this bus has a breaker on every component attached to it: Any and all feeder circuits, input sources from transformers, and voltage regulation devices. The relays watch the sum total of the electrical inputs and outputs of all of the things attached to the bus. They should sum to zero, as the bus does not keep any electricity for itself. If they don't sum to zero, the only plausible conclusion is a fault to ground, and all of the breakers attached to the bus are ordered by the relay to open, like breaking up the party and clearing all the uninvited teenagers out of the house. Bus faults are the worst thing that can happen to us dispatchers, particularly at large transmission stations. It just breaks the crap out of everything, often causing a serious disturbance when major transmission buses crater on us. Thankfully, bus faults and bus clearing events are rare.

The DISTRIBUTION BUS ZONE backs up the FEEDER ZONE. The relay that watches the feeder is responsible for telling that feeder's breaker to open. If that breaker fails to open for whatever mechanical odd reason, the feeder relay lets the bus relay know about the problem. The bus relay then rolls its eyes and clears the bus to handle the problem. Also, the bus relays watch the feeder and can detect the same faults that the feeder relays should operate for. If the feeder relay fails to open the circuit, and also fails to ask the bus relays to help out, the bus relay will eventually shove the unconscious feeder relay out of the way, grab the steering wheel and take over, again by dumping the bus to solve the problem. Relays on buses, as a rule, never attempt a reclose on a bus fault. One trip goes straight to lockout, and the station requires inspection before attempting to pick it up again.

The next segment is the TRANSFORMER ZONE. Like the bus zone, it is small. Its only job is to protect the multi-million $$$ transformer. Or at the least clear it before it boils and blows up and takes the whole station out. Like the bus zone it measures the in and out flows, but can also be activated by other sensed problems such as gassing in the transformer, or a sudden pressure increase internal to the transformer. And like the bus zone relay, transformer relays do not reclose breakers into a problem seen on the transformer.

The TRANSFORMER ZONE backs up the DISTRIBUTION BUS ZONE in two ways. If the bus attempts to clear and is unable for whatever reason to do so, the bus relay will ask the transformer relay to dump the source into the bus (the transformer). Similarly, the transformer relay can detect high loads, particularly high fault current at the bus, and will unilaterally dump the bus if the bus relay doesn't take care of issues at home fast enough. And, if for whatever reason the FEEDER ZONE fails to trip, and the DISTRIBUTION BUS ZONE fails to help out, the transformer relay will usually still sense the crazy high current and low volts and eventually throw everyone out of the pool.

Do you see a pattern yet?

Upstream from the transformer there may be a "high side" bus (higher voltage than the other side of the transformer). If so, there will be a TRANSMISSION BUS ZONE. It works on the same principles of the distribution bus.

Leaving the station, on the other side of the breakers attached to the transmission bus, are the high voltage lines, making the TRANSMISSION LINE ZONE. They work similarly to feeders in regard to how problems are sensed, but they usually are cleared by high-speed relaying and high-speed breakers, and usually also include automatic reclosing. These transmission-clearing setups are really amazing. The problem occurs, the relays sense it, the relays decide where the problem is, the relays decide which breakers need to be opened to solve the problem, the relays tell the chosen breakers to open, the breakers get the signal to open, the breakers mechanically do their thing and break the circuit.... from fault to clearing, sometimes as fast as 1/10th of a second or less, TOTAL. FAST.

All along the way, transmission lines, transformers and buses are all protected by their respective zones and the neighboring zones poking their nose in the goings-on at each point, ready to take over as needed. Finally, at the power plant end, there are zones protecting the power plant's station components, which are more or less configured in reverse of distribution stations but rated for higher loads. And then a zone from the yard to the generator. The generator zone has a bunch of nifty things it watches for that I won't get into here right now, but there are just bunches of things that will excite one or another relay and trip a power plant, especially the steamers (coal/oil/gas/nuclear/etc). At pretty much all points above the feeder circuit breaker, there are multiple relays that can sense faults not just in their designated area, but for good distances through other zones as well. The relays with overlapping detection have built-in time delays to give the local equipment time to handle it, but will do what they can to solve the problem if too much time goes by (usually measured in just a few seconds). I think you get the idea without me spelling it all out. Your eyes glazed over five paragraphs ago anyway.

Goodness gracious, what a long post! But wait, there's more! Next time.

What we learned: (1) The path from power plant to power outlet at home is broken into many segments, each protected independently and usually backing each other up. (2) The clearing is designed to remove only the problem, to interrupt as few people as possible. (3) We remember now why I didn't get back to the tutorial series for a while. They are way too freaking long.

That's enough. Out.

(Click this link to see all posts tagged "tutorial")

Thursday, December 3, 2009

The Six. Never Forget.

I just don't have much wit to share these days, it is a hard time of the year. The Lakewood WA incident still stings, and will for a while. And the beginning of December always harkens to the Worcester event. Has it already been ten years? Rest in peace, brothers.

Friday, November 20, 2009

Is this thing on?

Just checking in. Busy week.

Training new dispatchers is a drain on the soul. Some more than others. There's more I would like to say about it, but I'll leave it at that. I'm beat.

I need to get motivated to put up the next installment of the tutorial series, which will talk more about system protection (or rather, line tripping and fault clearing, that makes it sound more interesting). It really is among the most fascinating things in the job for grid geeks like me.

Translation for everyone else: Boring. But, many of you are polite enough to sometimes say something about these being 'insightful' or some such anyway. Y'all are so sweet to say such things, you know.

Speaking of grid geeks, one of my old mentors had a very amusing power grid-related cartoon on his office wall before he retired. Thankfully, he still had it when I asked him about it last week, with this blog in mind, and he passed it along to me for your amusement, now posted over there on the right. Click it to see it full size.

Stay safe, and I'll try to keep the lights on at the fire station.

Monday, November 16, 2009

Budget Cuts Fail

Is it still an Engine Company without a pump? Nope. I guess we can go back to calling it a Hose Company.

It's OK, though. In case of a big fire, just call for more companies.

Saturday, November 14, 2009

The Grumpy Dispatcher Gets Owned

So one night at drill, I stroll into the classroom a little late and find that the duty officer is leaving shortly and that I was put on the first-out engine in his place as the company officer (cringe).

I look at the assignments, and see a name I do not recognize. Turns out one of our newer members has brought his dad along, who is reportedly looking for an FD to join when he retires and moves to our area, and he has been assigned a ride-along spot on my Big Red Truck. That's cool. No problem.

After the brief classroom portion is complete, I find the guy and introduce myself. A very likeable guy, he's attentive and courteous in every way. I ask him if he's seen the engine yet, as I don't want any confusion if we get dispatched. We walk over and I show him the front-facing rear seat he'll be sitting in, and explain that the rear-facing seat has the SCBA and needs to be kept free for my crew. I tell him we won't leave until everyone reports being buckled in, including him. I tell him to go ahead and hang with us if we go out, follow along but try to stay out of the way, and we'll tell him if he needs to back off. I ask him if he's comfortable with that and if he has any questions for me before we start drill.

He's been listening patiently and showing some interest, and finally nods and says "I'm OK, I'm comfortable around this stuff".

Really? I say, What do you do?

"I've been a firefighter for Santa Barbara County for thirty years" he says.

Just jam that big ol' turnout boot down my throat, please.

He and his kid and several others had a great laugh at my expense - taught me to not walk into class late (after those guest introductions).

It was a perfect job, I'll have to remember that one for use later on.

Wednesday, November 11, 2009

Switching Error: The Verdict

Review: The Switching Error.

The review took three days to complete.

I had to write a lengthy narrative of the events as I remembered them. The station crewman and relay tech involved at the other side also got interviewed. All of my phone calls were listened to, more than once. Some of them were transcribed. My written switching and notes and electronic log were photocopied and sent places.

The 'short' version of events......

The station in question runs a 'dual-bus' configuration. That means each side of the switchgear is used to serve different loads. For protection purposes, the flows are measured across each transformer and then again out each bus, independently. If the "in" does not equal the "out", the logical conclusion is a fault or abnormal condition, and everything related to the faulted equipment is tripped.

We needed to flop one of the loads to another bus, and disabled this special tripping so that everything was counted as one combined sum instead of the two-bus method.

The relay tech convinced me, at 4AM or so, that it was a good idea to go back to the 2-bus protection while we had something flopped over. His motivation: They wanted to protect the thing being flopped over from getting knocked off by their work, and in the total-sum mode any fault anywhere in the bubble would crash the whole thing. Being the relay tech, responsible for installing and maintaining these protection systems, I disregarded the feeling of bad juju based on his "expertise" and being right there with the equipment, and let him do it. Stupid, stupid, stupid error. With one item on the 'wrong' bus, as soon as he toggled back to the dual-bus protection, both buses had in/out mismatches and both tripped.

Still with me? Heh.

FAIL. We dumped what we were trying to protect in the first place, plus everything else off those buses. EPIC FAIL.

Firmly back in charge and angry, I had them toggle back to the 'all together' mode and directed them to start closing stuff up again.

Problem was, one of the breakers that opened also lost its control power, and they couldn't close it back up. I'm still not clear on what the problem was with that, but those guys certainly knew the scrutiny that was now coming, so I don't doubt their motivation to get the breaker closed ASAP. It took an hour, being a Murphy's Law event and all. A preventable momentary interruption is bad, but an hour? Very Bad.

So.... today I learned that I am more or less off the hook. No letter in the file. It was characterized as split responsibility, and I am responsible for perhaps 10%, or something like that. Not free from all blame entirely but won't get pinned to the wall by any means.

I still feel fully responsible, as I know that this could have been avoided.

I got good marks for questioning the change of plan from the relay tech, demerits for folding on his advice against my judgement, but more good marks for taking command and responsibility, and for the extensive documentation. Also, I have a record rather free of blemishes. It didn't hurt that in the background on the tape, one of the guys at the station could be heard, right after it happened, saying "We really screwed up!". I didn't hear that at the time, though. I was preoccupied.

Anyway, they may have let me off the hook, but I still know I could have prevented it. This was the first significant switching error in my entire dispatch career. My best attempt to relate it to you fellow fire guys is the feeling you have when you miss a victim in your search, whether they were viable or not.

I'm unhappy. Grumpy, in fact.

Tuesday, November 10, 2009

MedEvac + Power Lines = Danger X2

Brought to my attention by Dave Statter, here.

The item of most importance: No one was hurt in this incident and the helo landed safely.

What I want to point out as the fire AND power guy, is that probably most people there did what the camera guy did: follow the helicopter. It's louder, more interesting, and presents itself as more threatening. Equally deadly, though, is the power line, which the camera guy eventually figured out was still live and not drawing enough fault current to trip. It might have initially tripped and then got popped on later by the dispatcher. It could be flopping around. Imagine how your attention would have been split if two lightly damaged helicopters were landing. That double-threat mindset is how this should have been treated: Two separate immediately lethal hazards.

Situational awareness keeps you alive. Tunnel vision kills.

Idiots With Stop Paddles

What happens when someone gives a stop paddle to one of the goofballs?
So I am on my way to work at the power company, still frosted about the switching error, otherwise minding my own business. I have arrived at a cloverleaf, passing underneath and getting ready to do the 270 and get on the other highway, when...

We're all stopping.

An aside: I know not many people do this, but Dad taught me to always look as far ahead as possible when driving. It's easy to spot the people who don't do that by noticing who gets surprised by being caught behind a bus at a stop that you yourself saw three blocks ago and changed lanes to avoid. They're all like "Where did this BUS come from??!" Duh.

Looking ahead during the approach, I noticed no backup on the upper highway, no backup on the ramp, so whatever is going on has just happened. I am about ten cars back and I still see nothing on the ramp. The cars stopping behind me are already blocking cars coming off the other 270 to pass under the overpass, backing them up on the curve. A collision back there feels imminent. I first assume that a wreck has just occurred, so, first checking behind me for other goofballs about to try the same stunt that I am, I then pull onto the right shoulder to approach, mentally remembering where my POV med kit is.

What do I see? A small pilot car for an oversize load convoy. He's just stopped in the middle of the lane, amber lights on, holding a stop paddle out the window. There is no oversize load truck in sight. He's watching a ramp for the truck to approach, but it is nowhere to be seen.

You have got to be kidding me, right? Daily tip: Close traffic right when you need to, but not until then. That's what radios and phones are for, to coordinate the timing. And do it in a position that doesn't cause cross-merging traffic to back up convergent paths. This is the dumbest possible place to pull the stunt he's pulling.

In some states and locales, fire and rescue folks have been arrested for closing the highway in order to protect fire and EMS crews. I know this isn't typical and don't mean to poke at my brothers in blue. I am just illustrating that even we fire guys don't have the authority to close the highway all the time, and better have a good reason when we do. And here's this goofball, sitting in his car, closing the highway in a very dangerous way and without immediate requirement, from the comfort of his front seat.

Oh, no you don't.

So I hesitate a bit to see if the big truck is going to appear. Waiting. Waiting. Waiting. OK, no truck, so I continue on up to where he's at. I can feel the evil stares of people I pass, who assume I am just going to zip by everybody. But I stop behind and to the right of the idiot, and get out, ready to give him a piece of Grumpy Dispatcher mind. Remember, I am still frosted about the switching error, and that was days ago.

No sooner do I get out and take about three steps to engage the idiot, and I hear a siren blurp at me.

Hello, Highway Patrol! The cavalry has arrived. I grin widely at him and give him the thumbs up, but I am in his way. He nods. We understand each other. I move my vehicle, and he moves up to engage the idiot.

I poke my nose out behind the Crown Vic. I roll down my window for a listen. I can hear his tone, he is not happy. Idiot quickly turns off his 'I think I am in charge but I am not' amber lights and pulls to the side. All those people back there who delighted in glee that I got followed to the front by a State Trooper are awaiting my turn to get tagged by the law.

Imagine their disappointment as he disengages to open the lane, me behind him, and off we go. End of incident.

Wish I had caught the name of the company with that flagger. That really warranted a follow-up call before he gets someone killed.

Idiots with stop paddles. Who knew?

Saturday, November 7, 2009

Three Mouse Clicks From...... Damn it

I don't have time to get into great detail right now, but suffice to say that sometimes it isn't a good idea to trust your protective relaying technician in the field at oh-dark-thirty when he says it is OK to go to a strange substation configuration that you'd really rather not do if given the choice.

As the Dispatcher, it is my job to verify everything. I trusted the guy who builds this stuff, and disregarded my gut feeling. His expertise notwithstanding, I am in The Chair, the one ultimately held accountable for what happens.

Click, Yeah, that third click created some interesting times. 2,610 customers were out of power for an hour this morning because I failed to listen to my spidey sense.

Hello, paperwork.

Hello, extended log entries. An aside: Always write so much in the log that no one calls you at home (waking you up) so you can fill in the details.

Just like police/fire/EMS incident reports, these things are legal documents, too. Be detailed.

And someone, actually multiple someones, will be reviewing all my phone calls for that time period. Good thing I kept the shared complaining about the company with my field crews to a minimum tonight. Kind of.

It is also a good thing that it is Saturday morning. Would have been a lot more folks late to work if this had been on a weekday morning.

Damn it.

More later. Have to clean the mess up before shift change.

Friday, November 6, 2009

Your Thoughts and Opinions, Please

OK, I am humbly requesting feedback from my small pool of regular readers who aren't afraid to admit coming back here more than once to read my drivel.

The comments attached to the last few power grid tutorials are, well... they aren't. I am out of touch with how they are being received.

Are they working for you?

Are you learning anything?

Am I going too fast?

Are they too long?

Using too much jargon?

Do you care?

Is there something specific on the grid you want me to talk about?

Should I give up on it all and just make this another fire blog in blogosphere already getting crowded with better fire blogs than this one?

I just need to know what you want, so I can deliver.

Thanks for indulging me with your thoughts.....

Wednesday, November 4, 2009

Evacuation Modesty Fail

Dude, you were caught so entirely off-guard you couldn't even grab your boxers?

Cappy? Monitor the evacuee's progress, or avert your eyes? Stay close enough to grab him if he stumbles, or...... well, Mom said there'd be days like this.

Sunday, October 25, 2009

Hottest Costume of 2009: Illegal Falcon Alien

A Grumpy Dispatcher Original Creation.

My apologies for the image quality, I am not working with my normal tools here.. I had to scrape this together with MS Paint. Ugh.

Anyway... After Falcon Heene (didn't) make the infamous balloon flight in Colorado, I present you with the Illegal Falcon Alien costume.

Thanks, I'll be here all week.

The EMS 2.0 Buzz -- and Requisite Rant

I'm not under any illusions that people are reading this blog to learn what's going on in the fire/EMS universe. That's what Firegeezer and Happy Medic Headquarters and Fire Critic and others in that league are for. I don't hope to ever be that popular, and it is probably best for me to stay that way anyway.

So, no doubt you've heard of EMS 2.0 already. It's the latest buzz, and while I certainly like the concept, it is picking up steam so fast... almost too fast, and I am worried about it spinning out of control before liftoff. I want it to be useful, and not over evolve into a bigger mess than we already have. I have my popcorn handy though... should be fun to watch.

I had an event a few weeks ago that was almost bloggable, but not really. But then again, it was a silly event. And then it further dawned on me that my silly event was obliquely related to EMS 2.0.

Woo hoo! That's enough to go with. And I can use "EMS 2.0" in a blog post! I've arrived!

OK, seriously....

While the aspects of EMS 2.0 I have seen the most of involve a more dynamic outcome-based approach to providing initial contact medical assistance, to best utilize our resources, the aspect getting slightly less coverage as I see it is on the initiation side.

This is of course assuming I know what I am talking about. Perhaps I should stick with the power line stuff.

Anyway... I'm not sure how to move away from our current EMS initiation model, due to the litigation-driven culture we exist in here in the States, but at some point we have to stop throwing resources at problems when they're known to be not needed or not even asked for.

And so here's my silly personal story.

I was minding my own business, driving in the City, when I stumbled upon a two car "T-bone" blocking collision. As I pulled past the vehicles doing the automatic habitual size-up, it looked like all occupants were out, no airbags. It wasn't that hard of a hit.

I pulled off the road and made sure my cell phone was handy, but didn't want to call it in until I had useful information for the 911 dispatchers. As I approached, the drivers were moving their vehicles off the road.

No spills, no major hazards, no traffic problem. Looks like I am not needed. Still, I checked with them to be sure.

One of the drivers asked for law enforcement. All involved explicitly denied any desire for fire or EMS. Now, I am not convinced the brothers in blue are needed, either, for a non-injury accident with no tow truck required. I mean, c'mon, let's trade insurance info and move along. But they asked, I had the phone, I said I'd at least pass along the request.

911 Dispatcher: 911, what is your emergency?
Grumpy Dispatcher: Hi, this is firefighter Grumpy, I'm on scene of a non-injury, non-blocking accident at 45th and Main, and I have one of the drivers requesting law enforcement, if you have any units available.
911: You say there are no injuries?
GD: That's affirmative, all three involved parties are out and not reporting any injuries. One of them is rubbing her neck, but they're all OK.

What the heck, why did I just say that? Dang it, now I've gone and done it.. Crap.

911: You said someone is holding their neck?
GD: (sighing) Yes, but they have already declined medical attention.
911: OK, we're going to go ahead and send fire and medical just to be sure, so they can get refusals.

I had already played the FF card, so if my advice was going to be followed up front, we would not already be this far. No value arguing now.

GD: Well, since they've declined EMS, a Code 1 response is probably appropriate.
911: OK, they're on the way, thanks for calling.



The drivers are exchanging information now. I approach to tell them that fire is on the way even though I said they weren't needed.

A minute or so later, I hear them. Yeah, 'hear'.

Rescue 14, then Engine 14, and then a private Medic arrives. All Code 3, all busting the nearest intersection to get into the parking lot we're in.

I sheepishly apologized to them and gave them the quick rundown. Refusals were obtained. Units returned to service. The guys knew the score, this kind of Code 3 refusal errand is not unusual here.

So at what point do we go back to realizing refusal forms need not be filled out unless crews are on scene in the first place? At what point can a dispatcher follow the advice of a verified FF to modify a response, or to cancel one... or not start one in the first place? If I had been on the radio, the cancel would have been heeded. Why not by phone? I'm still FF Grumpy, so why does my authority change depending on how I communicated?

EMS 2.0, we eagerly await your arrival. We'll be at the dock, waiting. Unless we're on our way hot to get another legal document signed.

Tuesday, October 20, 2009

Identifying the T-Shirt Firefighter in its Natural Habitat

This is a Public Service Message. Don't be a T-Shirt Firefighter (TSF).

I'd like to assist you in identifying a TSF should one be in your vicinity. You may be acclimated to their presence and no longer recognize them. Worse, you may be one and not realize it. Acknowledging you have a problem is the first step to solving it. I recovered. So can you.

A TSF is a firefighter who attaches more importance to wearing a uniform fire department T-shirt than knowing or doing the job itself. TSFs come in all varieties: Career, part-time and volunteer, even non-firefighters have been known to be a TSF. A TSF will wear a uniform T-shirt to all events, even a wedding or funeral, just so everyone 'feels safe' and the ladies know or assume his career.

When wearing a uniform T-Shirt, the TSF will make sure his back (with the largest-possible white lettering "FIRE" etc.) is frequently flashed towards other potential alpha males in the room to discourage them from approaching mating females near the TSF's territory.

Fledgling TSFs may attempt to mimic older, experienced Real Firefighters in ways similar to certain insects that have evolved markings to resemble something different and generally more dangerous in order to ward off enemies. One such method is to repeatedly wash and wear their shirts so that they look well-worn. This leaves the impression that their plumage has naturally faded due to exposure to The Job. This actually is quite easy to accomplish, since they wear the T-Shirt almost every day anyway. It is frequently possible to distinguish the TSF from the Real Firefighter by comparing the relative age of the wearer with the apparent age of the T-Shirt. When the T-Shirt appears older than the wearer, you have likely found a TSF. There are exceptions, as some TSFs live to a fairly old age. Actual Firefighters use old shirts for painting, working out or sleeping, but never on duty or in public.

Sophisticated TSFs that have evolved beyond the basic T-Shirt appearance have developed alternative plumages which come in many forms, a few examples of which are below.

More mature TSFs which desire something additional to display to other potential alpha males than their shirt alone have adapted accessories to this purpose. The preferred accessory is a portable radio, especially when a simple pager would otherwise be adequate. Newer modern compact designs are beginning to gain popularity but there is still no substitute for the unmistakable bulk of the Motorola HT600 or MT1000. Additional radio size can be gained by wearing this radio using a leather wraparound holster hanging off of a belt or a shoulder strap with a reflective stripe, and additional flair can be added by labeling the radio or holster with "METRO FIRE UNIT 565" etc, using reflective or high contrast materials in the largest size possible. This is as close as a pedestrian can come to resembling a Big Red Truck.

Fledgling TSFs can compensate for their lack of radio by obtaining a hand-held scanner from Radio Shack and affixing similar labels to disguise their decoy scanner as a real radio. In all cases, the radio accessory can be enhanced by insisting on wearing two or three pagers and a cell phone alongside it. Seasoned accessorized TSFs usually are unable to wear their pants level due to the resultant drag on one side, and the many accessories may even cause a slight limp over time that can conveniently be implied as an old firefighting injury.

TSFs not satisfied with the radio accessory alone have adopted some behaviors exhibited by the T-Shirt Medic (TSM), namely equipping themselves with pocket CPR mask carriers which are replaced as soon as the printed "CPR MASK" wears off the case. The second most-favored borrowed accessory is the glove pack, rendered most effective if the ends of two gloves are visibly hanging out of the pack. Other variants on this behavior include displaying shears, seatbelt cutters, first aid tape, penlights, etc. It seems inevitable that evolution will eventually result in a day where TSMs will attempt to carry a small six-minute O2 canister strapped to their leg, an ability which will no doubt soon be passed to the most advanced TSFs.

The mating call of TSFs - which they may continue to broadcast despite its dubious effectiveness - is the sound of a pager or radio dispatching a job at the loudest possible volume in any part of their natural environment, which includes worship services, movie theaters, formal dining establishments, etc. A determined TSF also uses the mating call of competing TSFs as well as Real Firefighters by emitting the mating call of every agency within a 50 mile radius as if it were its own, and showing grave concern over "white smoke seen coming from a chimney" for an agency three districts away. When actual mating possibilities seem dubious despite the mating call, the TSF may attempt to save face upon their exit by departing as if off on an important mission, regardless of whose mating call was actually used in the failed attempt.

Now that you can reliably identify the TSF should one have established their habitat near you, you are able to avoid or rehabilitate them as seems prudent to your situation.

That is all. Be safe today.

Sunday, October 18, 2009

Fire Hydrant as Grounding Rod Fail

Deftly blending power grid stuff with fire department stuff yet again... not sure how long I can keep this up!

Actually, attaching your neutral grounding wire to a hydrant is electrically very effective. Obviously, not such a good use of fire protection resources, though.

Saturday, October 17, 2009

Tutorial 8: Introduction to System Protection

What have we learned so far? We know the difference between AC and DC power, how energy is scheduled and accounted for, how it is decided which generators will run and how high, how interconnected power companies help each other out when they lose a unit, and quite a bit about power lines from big transmission to little distribution.
Has this been helpful so far?

Today's topic is in regard to why the system protects itself when bad things happen.

The system protects itself for two reasons: To prevent damage, and to maintain stability (ie. not collapse the whole house of cards). Although the correlation is not precise between fire hydraulics and electrical flows, nonetheless major system disturbances can have far-reaching and disruptive ripple effects that could be compared to the water hammer effect.

Extremely high or low amp flows and voltages pose a real threat of causing permanent damage to everything exposed to the swings, from multi-million dollar substation transformers all the way down to your DVD player. It is far better to instantly disconnect the world and drop the whole potato, because if you save the equipment, you have something to put back together. If you disconnect late, there isn't much point in trying to restore a system made up of fried parts.

When voltages and flows go to pre-programmed extreme limits (by line/equipment faults or simple overflows), protection systems activate to remove elements from the system in order to prevent damage to the transmission infrastructure, and also to prevent damage to customer equipment. It isn't unusual for a 'ripple' to occur when elements are removed, resulting in momentary spikes in flows and voltages, sometimes causing more elements to be removed, causing more ripples, causing.... yeah. There are well-paid transmission protection engineers who spend their careers trying to balance instant protection of the assets with not crashing things worse. Frankly, I find that stuff fascinating, but don't want their job.

It is a testament to those protection engineers that hundreds of major transmission lines and thousands of distribution circuits trip out as a matter of routine every day all across North America for all reasons imaginable, yet system protection isolates the problem so quickly that the vast majority of problems are cleared in seconds or a fraction of a second. Unless it is a distribution circuit that tripped and you're on it with several hundred other people, you don't generally notice that anything happened anywhere else.

The August 2003 Northeast blackout in the United States was a major comedy of errors and things going exactly wrong. How is it described by those dissecting airline disasters? An unfortunate sequential confluence of unforeseen events, or something like that. Super rare. It will happen again, but the 99.999999999% norm is that it doesn't, which is remarkable when you take in the scope and complexity of everything that goes into this machine.

For what it is worth, system disturbances do cause split-second bumps that go by faster than a blink of the eye in areas regional to the problem. Most dispatchers are attuned to that, and see it in a momentary hiccup in the lights several times a day at home and at work, often knowing a trip alarm is coming one or two seconds before it appears on the console, or wryly smirking when seen at home, knowing that some dispatcher is about to get interrupted. Sometimes we see it and the alarm doesn't come in, because it happened on a neighboring system. That said, these happen so fast that almost no one else notices them at all. Which is how we like it.

System protection is done in layers, in a way that breaks up the chain of transmission from the power plant to your breaker panel into many segments. Each segment has something protecting it, and each segment has at least one higher level of protection in place if the first one fails. And if the backup fails, the backup is backed up at the next level. And so on. Sometimes protection settings are not tight enough or sensitive enough (to wit: Must-See Video of Line Fault and Reclose) and issues happen, but the concept is generally very reliable.

I think that's enough for today. It's Saturday. You get the general idea, but no math or excessive technical jargon, nor homework.

What we learned: There's a ton of mysterious stuff set up out there designed to prevent blackouts, by removing faulted and overloaded parts of the grid faster than Barack Obama earns Nobel Peace Prizes. Oops, I said I wasn't gonna do that again. Sorry. And if you know a dispatcher and you see a minor nervous tic once in a while, don't worry about it, they just detected a line fault hundreds of miles away with their spidey sense, that's all.

Technical stuff next time. Don't worry though. It's pretty cool. Well, to some of us. Take it easy for the rest of the day.

(Click this link to see all posts tagged "tutorial")

Friday, October 16, 2009

De-Motivational Poster

I'm not planning to make this blog political or anything, but after recent events I couldn't resist putting this little gem together.


Oops, there went a bunch of followers. I knew I shouldn't have posted anything political. I was no fan of George W, either, OK? Oh well, I'll try to not let it happen again.

The next Tutorial will be forthcoming in the next day or so. In the meantime, stay safe out there.

Saturday, October 10, 2009

Taking Care of the Children

So what do you carry on the Big Red Truck to take care of the kids?

No, I'm not talking about peds and infant-sized airway stuff, small cuffs, or the somewhat horrifying peds BVM and AED pads... I get a small shudder from the thought of the next time I will need any of that stuff. Oh, how those calls just... suck. Having children of your own... well, if you have kids, you know, I don't have to go there.

But that's not what I am asking. What do you have to take care of the kids when they're not the primary reason you're there?

One of the Captains established the 'Kid Kit' several years ago, and it is checked at the beginning of every shift along with everything else on the dailies. The kit includes the kind of stuff many of us are giving out right now during Fire Prevention Week in the states: coloring books, pencils or crayons, stickers, those flimsy fire helmets, and other sundry prizes. Of course we also carry at least one 'Trauma Teddy' on each piece, but that isn't always the thing you need.

We use it fairly often, but one specific episode still stands out to me. We arrived to the home of a female having a nondescript but legitimate medical emergency. There were three small children present and no other caretaker was available. Arriving 2nd due, my personal presence was not really needed. I saw that there are three very worried children observing us, clearly aware that Mommy is quite sick.

Thank you, Captain Bill, for the Kid Kit. I returned with it and showed Mommy what I had in front of the little ones, so they saw that Mommy approved, and then shepherded them all to the kitchen table. Soon all were distracted by coloring books and stickers. A trauma teddy works to comfort, sometimes, but it doesn't distract like a coloring contest with your siblings.

By the time we moved Mommy to the cot and headed to the door, Mommy had made it clear to the kids that a couple of us would be watching them for a bit, something we were happy to do until child services or PD could make the scene. I told the kids, truthfully, that Mommy was going to be OK and probably back home soon. Those kids were so relaxed that they stayed in their seats and waved Mommy goodbye as she was wheeled out.

The popular Trauma Teddy idea is a nice start, but its applications are limited. It doesn't take much to expand that kit a little bit, and the returns are worth it. Happy parents tend to then think highly of us, and are more likely to vote 'yes' for much-needed funding measures, and are more likely to tell their friends to support us as well. We all know how fast bad PR spreads, but good PR makes the rounds, too. The good PR earned with your Kid Kit is worth exponentially more than the monetary cost invested to put it together.

My suggestions for your Kid Kit inventory:
* Coloring Books
* Crayons
* Gimmick Pencils (three-color or bending, etc)
* Erasers
* Rulers (a universal toy!)
* Mini flashlights
* Small wind-up toys
* Play stickers
* Badge stickers
* 911 stickers
* Play fire helmets

Obviously some of these things don't go to the choking-hazard set, but you knew that already.

Give it a try. I bet many of you, especially the fire guys, already have a lot of these things in a supply closet at the station. Throw some of this stuff into a bag and put a rudimentary Kid Kit in service today, and see where it goes from there.

Thursday, October 8, 2009

Wednesday, October 7, 2009

Must-See Video of Line Fault and Reclose

Check this out:

If you've read over the previous two tutorials, you'll note how far above the three phase feeder these wires are, which makes this at least subtransmission voltage. I am guessing by what I can see that the involved circuit is probably 69kV - but don't hold me to that.

These people are entirely too close to this action. If the conductor were to melt and break from the heat of the arcing, the wire would recoil quite a long ways, and fall into the feeder, making more fireworks. These people are living out 'If Only We Knew How Stupid We Were'.

The extended duration of the fault is clear evidence that you cannot always depend on transmission or distribution circuits to clear quickly after a fault. We'll get into system protection and fault clearing in a future tutorial.

In any case, you spent most of your time watching that clip with the sustained arc in the tree, imagining how much power is in there. But then, when it finally 'flashed' at 4:02, that's when the full force of the 69,000 (?) volts coursed through the tree. You can see that I am not overstating the force when I make snippy comments about arms getting blown off.

Finally, it's dead, it's safe. Wrong. You saw it yourself, the line came back to life 10 seconds later through automatic reclosing, and carried the fault current for an additional 5 seconds. In addition, though it didn't seem to happen here, chances are excellent that after the second clearing event, a dispatcher may have waited a minute or so and then manually tried it one more time in case whatever was wrong had time to fall away.

That's all..... 'nuff said.

Thanks to Dave Statter for bringing this to my attention through his blog.

Why Tutorials 6 and 7 are Worthless

It's great and all that you can marginally identify stuff on the pole... as long as things are intact. But when things are intact - speaking mainly to my emergency services brethren - you are far less likely to be involved in the first place. It is when things are not intact that all bets are off. What good is it knowing what's what when it looks like this over the car wreck you're working?

Hands off. Call for backup from the power company. Keep everyone out. But, you knew that already.

Tuesday, October 6, 2009

Tutorial 7: Identifying The Wires, Part II

Welcome back. I have some old material that I wrote a ways back for another cause that I am bringing in here to recycle, in order to expand on the cause of identifying stuff on power poles. I took all of these pictures myself, so am more familiar with what's in them than the generic reference pics I used in the last tutorial.
This is going to be a VERY long post. Go refill your coffee now, get your potty break in, and then come back when you're ready to sit a spell. I am confident that, despite the length of this post, you'll be pleased with the information you pick up from it.

I think it is high time to put in a disclaimer, however.

I am a power dispatcher, but I have never been a lineman. I know enough about this subject to sound like I know what I am talking about, but any lineman knows enough to make me look clueless. If you are dealing with someone on site who should know what they are talking about (power company field employee), don't rate my info better than theirs.

Click on these pictures in order to open them up in a larger window to see better. If you 'right-click' the picture, you should be able to choose to open it in a new window, so you can have the picture up full size while also reading the text.

In this picture, three conductors of this 14kv feeder are coming in from the upper left, and traveling towards the lower right, they are the wires at the very top of the front pole.

Under the top crossarm of the front pole there is a three-phase tap (all three conductors are tapped), and these travel downward in the photo to the pole across the street where they are then on the very top as they go off the left side of the photo. Also, on the right side of the lower crossarm is a single phase tap that travels off the right side of the photo.

So far, all of what has been described is 14kV, bare cable (not insulated).

Now, across the street you see the streetlight on the back pole. Just above where the light attaches is a triplex cable. Off the left side of the photo and out of view is a poletop transformer that steps down the 14kV to something the street light can handle, and the 120v insulated cable coming back from that transformer is wrapped around the neutral to form the triplex. The triplex then extends to the front pole and terminates. You can see on the right side of the front pole that the triplex at one time continued towards the right, but it is no longer in use, as the right side has been disconnected and is bundled back towards itself. The triplex on the left is hot, the triplex on the right is not (I only say this because I know what happens to the triplex off the right side of the photo, it dead-ends at nothing). Also, at the same point on the front pole, you can see the lone neutral wire coming in from the upper left and following the single phase tap off the right side.

Below the neutral is telecom stuff (cable TV and/or telephone) on both poles.

Remember that ANY wire can be hot: Neutral, cable TV, phone. Say for example a power pole is broken as a result of a traffic accident. The innocuous neutral or cable TV line may have whipped backwards and draped over a high voltage line before landing on the ground. Always visually trace the path of wires on the ground to their source regardless of the kind of line that is on the ground! Check for things contacting the guy wires, too!

This is a different section of the same feeder. The 14kV uninsulated conductors are on the top crossarm.

Just below the crossarm is the poletop transformer, stepping the 14kV down to 120V. If you look very closely you can see that only the back of the three phases is tapped by the transformer. A solid rule is that a lone poletop transformer will only be connected to one phase of high voltage. As you go down a feeder you will see how transformers are tapped off of the different phases more or less sequentially (A B C A B C etc) to equalize loading on the three high voltage phases. That little gadget in the tap between the conductor and the transformer is the fused cutout, the fuse is a cylinder not quite 12" long in a spring clip or hinged apparatus. It can be opened/removed to de-energize the transformer and its taps.

Under the transformer the customer taps fan out. These transformers frequently may have only one tap, but there is no reason they can't have several, like this one. Starting with the first one that points almost straight left and going counter-clockwise, the first one goes to a house, the second one goes to the next pole (and thus is on the main neutral) to serve a street light, the third and fourth go to houses. The wire heading sharply down towards the right is just a guy wire. Heading from the transformer off the right are two more lines. One goes to another street light across the street, and then above that you can see the bare neutral going off the right but staying on this side of the street. Remember, all of these insulated cables are at the same potential as household current, so although a hazard exists it's not big time stuff.

Under all of that is telecom.

This is a fused poletop switching point. Each of the three phases has an inline fuse (basically like the poletop fuse in the last post but with a higher rating). The fuses will pop as needed so that the entire feeder doesn't have to go dark for a fault on the far side of the fuses. Since it is a switch, the three fuses are attached to hinges so they can be collectively opened for work clearances on the far side of the switch.

This one is a little more complicated.

You see the familiar three phases on the crossarm on top. On this pole, all three phases are tapped to inline fuses on the right side of the lower crossarm (at a right angle to the upper crossarm), then onto small insulators on the left crossarm and then into individual transformers. This is a large customer requiring three-phase service. The three phases and the neutral are individually tied to the pole instead of them being wrapped together, so you see four wires leading to the customer, but often they will be wrapped together and referred to as quadplex. You can also see that one of the low side lines is tapped for something else since it is running wrapped around the neutral to the far pole for something else.

There is some increased danger here. The three phases are tapped into inline fuses before the lower crossarm, and then converted into insulated cable before heading into the riser tubing and going down the pole underground. Note that there are no transformers in sight on this pole. This means that the cables running down the pole behind a little flimsy sheet metal are a full 14kV. Smack a car into this pole hard enough and/or in the right place and you'll get a dandy light and sound effect show for a second or two until the fuses blow. Long enough to kill you for sure. Tread carefully here.

I think everyone can identify the neutral and cable TV/phone here, right?

Another poletop switch, this one with bladed disconnects on the top of the crossarms, is on the right pole. A three phase customer is tapped off of the pole on the left. Linemen like this kind of switch a little more because it can be opened without a bucket truck. If you look close at the pole on the right you'll see a control rod going down the pole. This can be operated by hand with a hotstick while standing on the ground. Some control handles go all the way to the street level, and in these cases the control is locked in position with a power company padlock.

You might conclude that in an EXTREME emergency, you could theoretically open the switch, but this is a bad idea in every way. Linemen wear linemen's gloves for this kind of switching (for all switching, actually), because you never know when the switch is going to fall apart and something energized falls into the switchgear. Plus, you'd have to know without a doubt that there was no potential from the other side of the switch for it to be worth your trouble. And don't forget some dope might have an incorrectly installed generator on auto start on the dead side which would heat you up a few seconds later. Or... there might be an "auto flop" configuration installed by the power company to automatically energize from somewhere else down the dead line in an attempt to restore some customers after an equipment failure. You can see why there are far more chances of failure than success, plus major personal safety hazards in attempting it. Just put it out of your mind.

The picture on the left is a better angle on the this switch and control rod - that you won't be touching.

Here we have the point that three phases are split into different directions, but they are still elevated distribution voltage.

The three phases come in from the upper right. The left phase can be seen as tapped to the upper wire going off the left. The middle phase dead-ends here. The right phase taps off to the upper wire going off the right. You have to look close to see it, but the second wire that looks like it is right next to the right phase is actually the neutral and goes to a point on the pole about 3' below the crossarm, and it also splits so a neutral is continued with each of the tapped single phases.

The three wires going downward on the left are guy wires. Since this pole is a dead end, there is a lot of tension pulling in one direction, the guy wires make up the difference so the pole is not yanked over.

What you have here is some 34kV subtransmission on the right side tapped to underground. While it is underground and out of sight, it goes off the picture frame about 200' to a large pad-mount transformer where the voltage is reduced to (I think) 8kV. That's still 8,000 volts even on the 'low' side. Then it comes back through the underground and back up the pole on the left before being distributed by feeder to local customers. On both poles you have three phases of either 34kV or 8kV behind a relatively flimsy shield of sheet metal.

Even though there are not major differences in the size of the insulator bells on either the 34kV or 8kV to help you figure out which is which, the different sizes of the cutout fuses ('C'-clamp looking things) mounted below the crossarms gives the difference away. High side, low side, doesn't really matter, it'll all blow your arm off.

This is next to a two-lane 60 MPH highway. Can you imagine what would happen if a vehicle took out one (or both) of these poles and also careened into those propane tanks? Big Fun!

Over here on the left, doesn't look like much, but this is 115kV, about 8 times higher voltage than most of what we've been looking at so far. Note the two shield wires above the three conductors.

This is outside a power plant.  The other wires crossing by are a distribution underbuild (meaning it runs under something larger), of the 14kV variety we've already been learning about .

Over on the right, this is twice as much voltage as above, 230kV. Again, note the shield wires.

On the left, this should keep some people honest... this angle shows that the wires some people are afraid of (because they are on lattice steel structures) can also be found on wooden pole structures that aren't as visually menacing. The voltage is the same on all of these, all 230kV stuff from the same substation. Note the quantity of insulators instead of judging by the structure. Better yet, stay away no matter what.

This is 34kV subtransmission coming in from the upper right and being stepped down to (I think) 8kV distribution. This is a cheap way to get around building a proper substation behind a fence. The box on the second set of poles is a field recloser, the device which will open for a fault farther along the low side and then may attempt to reclose the line one or more times. If the fault self-clears, the customers see an outage of a second or two. If it doesn't clear, the recloser will give up and stay open.

This tower on the left is one of the big dogs, a 500kV line, over twice again as big as the last big line picture earlier in the psot. If this is laying on your structure you better be a long, long way away from it.

As mentioned in the last tutorial, one clue to extremely high voltages is the presence of multiple conductors per phase. In this case, each phase is made up of three cables. You can see little triangular brackets holding them in place along the line. Then there's those really long insulator strings to clue you in.

Once again you can barely make out the shield wires way up on top.

On the right is a close up of the triple conductors on the 500kV line.

The parting shot illustrates another exception to the rules. I kept going on about high voltage transmission lines always being present in threes, and here you can see there are only two conductors on what in every other way looks like high voltage.

This is one of the small handful of high voltage DC transmission lines in North America. Six DC lines tie the Eastern and Western electrical interconnections across the Rockies, two DC lines tie Texas to the rest of the U.S., two DC lines tie Quebec to the world, and there are probably no more than 10 or so major DC lines anywhere else in North America. Other than the interconnection tie points, they always go a long long way (many hundreds of miles) when they are built.

All major AC lines, the stuff that makes up 99.9% of the grid, are three phase and require three conductors to be in service. DC lines are singular, thus you can run either one of these individually, but normally both are in service. So, despite the 'rule of threes', here is a way you can get one or two cables of high voltage, and these run at around 250kV. The long insulator strings should give away the high voltage present, anyway.

What we learned: (1) You can now impress your friends and coworkers by identifying the clutter on poles. Impress them further by showing that you know enough to stay away from all of it no matter what. (2) The Grumpy Dispatcher's posts are waaay too long, except for those nifty FAIL pics he puts up once in a while.

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