Power Outage

[arsenal]

The body that ordered the rolling blackouts is AESO (Alberta Electric System Operator). 30 minutes here and there is better than the whole grid coming down ie: The huge blackout that affected the NE US and Canada.

[ken0042]

Originally Posted by arsenal

30 minutes here and there is better than the whole grid coming down

Agreed. But seeing as it was a controlled blackout- couldn't they leave things like traffic lights and the C Train with power?

[V]

Originally Posted by ken0042

Agreed. But seeing as it was a controlled blackout- couldn't they leave things like traffic lights and the C Train with power?

I'm kind of surprised the C-Train doesn't have a backup generator system. As far as I know it doesn't take a lot of power, so it wouldn't take much to back it up I would think. I'm not sure, though.

As for traffic lights, I don't think the control is all that fine. I would imagine a controlled blackout would involve shutting down portions or all of certain substations at certain times, and there's no way to shut down the power for houses, but not traffic lights. The power cabinets for traffic lights are just a tiny piece of the whole grid.

[arsenal]

Originally Posted by Dominicwasalreadytaken

As for traffic lights, I don't think the control is all that fine. I would imagine a controlled blackout would involve shutting down portions or all of certain substations at certain times, and there's no way to shut down the power for houses, but not traffic lights. The power cabinets for traffic lights are just a tiny piece of the whole grid.

Exactly.
You open the connection at a substation, and that cuts off all electricity that was fed by that substation. AFAIK there is no "secondary" connection run traffic lights or the C-Train, but it may come in the future..

[V]

Naw, it would be incredibly expensive to provide a system that would allow the feeds for traffic signals to be unaffected when a portion of a substation shuts down. You'd need a whole new set of lines just dedicated for the traffic signals. We're talking tens (hundreds?) of millions just for one quadrant of the city alone.

Even if they wanted to implement some kind of addressable system (sort of like DALI for lighting, or a fire alarm system), it would be far cheaper, as you'd only be sending signal wires along the existing power lines, but still. That would be signal wiring along every single power line in the city. The labour for a task like that would be staggering.

[J pold]

Over in McKenzie I was fine

[ken0042]

I just seem to recall a brown out around 1993 when the entire west coast lost a lot of it's power grids, that in Calgary we ended up having every 3rd street light still on.

Maybe I was just drunk at the time or something.

[V]

It's possible that there was a mish-mash of lights being on, and some off, but that would have more to do with the fact that the voltage was probably affected to the point that a good chunk of the ballasts weren't working properly. The way street lights are circuited, if one light doesn't have power a whole string of lights won't have power.

[HelloHockeyFans]

Originally Posted by the_only_turek_fan

I live in the NW, and we had an outage in that same time slot.

The explanation to the best of my knowledge is that there are too many people using electricity which means there is an increase in the amount of current that is drawn, which in turns makes power lines sag. This makes the lines vulnerable to a fault.

Dan, Kevin, am I on the right track?

Well Sunil, as some of the other guys here already mentioned, your explanation isn't correct, but it's not nearly as bad of an attempt as some of them might imply...

There are soooo many possible explanations for an outage, but weather and mother nature is the answer most of the time.

The over-drawing of current is correct, but it's not because there are too many people using electricity at once. Power grids are designed with this in mind, wouldn't you think?

Systems are so sophisticated these days and completely computer controlled that whenever it senses added loads to a particular region, backup UPSes kick in to meet the demand.

Most likely, the outage was due to a sagging power line shorting through tree limbs (which should have been trimmed) and cutting off the path. The particular line was likely a major path supplying a particular area causing the outage.

Another explanation would be "rolling blackouts" (when power companies intentionally cut power off to certain areas) which power companies deploy every now and then (usually during peak times when the most electricity is being used) to keep power consumption down. They usually go on for an hour to three hours and most of the time they try and notify the people it will affect.

[shane_c]

Originally Posted by ken0042

I live in Copperfield. Looks like the power was out here, and came back on 1 hour and 12 minutes ago. (My clock starts at 12:00 when the power fails.)

No interuption in McKenzie Towne.

[arsenal]

Originally Posted by HelloHockeyFans

There are soooo many possible explanations for an outage, but weather and mother nature is the answer most of the time.

The over-drawing of current is correct, but it's not because there are too many people using electricity at once. Power grids are designed with this in mind, wouldn't you think?

Correct, weather is usually the main cause.

As far as electricity goes, electricity companies are required to have a pool of electricity at all points during the day that their customers draw from. The amount of electricity in that pool is set by AESO, and i beleive it is set to be about 5% to 10% above normal load. As more load comes onto the grid, the companies are supposed to add more electricity to the grid to keep the pool at a safe level. The problem right now is, load is higher than normal, and it is inside the "danger" zone of reaching the limits of that pool, and there is not enough electricity available to add to the pool. If the load did reach and exceed that limit, the entire province, and i beleive parts of BC, Washington, Idaho, montana, sask could go down as well.

[photon]

Originally Posted by Dominicwasalreadytaken

There is absolutely no truth to that statement. It was pretty funny to read, though.

Power lines do sag when they carry more current. Not because of increased mass, but because of increased heat (more current through the wire's resistance).

That's part of what caused that big blackout in 2003.. there were a number of lines that sagged into trees because of the increased load.

[kermitology]

Originally Posted by photon

That's part of what caused that big blackout in 2003.. there were a number of lines that sagged into trees because of the increased load.

The trigger perhaps, but that wasn't the real cause.

I've got an explanation of what happened, but it's at home.

Sunil is right about the power lines though. It's because of the heat caused by the increase in current in the steel powerlines. As they heat up, they become less rigid and can droop into trees that encroach on the powerlines right of way. But... that's not what happened yesterday.

[V]

That would have to be an awfully crazy increase in load if it's going to affect the lines enough to increase sag by a few feet. Those lines are under an awful lot of tension.

[photon]

Originally Posted by kermitology

The trigger perhaps, but that wasn't the real cause.

I've got an explanation of what happened, but it's at home.

Sunil is right about the power lines though. It's because of the heat caused by the increase in current in the steel powerlines. As they heat up, they become less rigid and can droop into trees that encroach on the powerlines right of way. But... that's not what happened yesterday.

No yesterday was something else.. just wanted to point out that the concept of power lines sagging is real, not that there's no truth to it.

It's a real problem in the industry:

http://www.spectrum.ieee.org/jun06/3674

[photon]

Originally Posted by Dominicwasalreadytaken

That would have to be an awfully crazy increase in load if it's going to affect the lines enough to increase sag by a few feet. Those lines are under an awful lot of tension.

They're also crazy long. Lines can sag 15-20 feet!

http://www.wapa.gov/newsroom/pdf/treesandpowerlines.pdf

[V]

Yeah, for some reason I had distribution lines in my head, and didn't even think about transmission. There's no way an increase in load could do this to distribution lines, as the available increase is so minimal. Transmission is a whole nother story. I shouldn't have been so quick to dismiss totf.

[ken0042]

Came home and found the clocks blinking again. Anybody else?

[ken0042]

Oh, is it a puppy! I bet it's a puppy!






Edit- it wasn't a puppy.
Unless somebody has been feeding him corn.

[FurnaceFace]

Originally Posted by calculoso

On my way home, QR77 explained it like this:

Rotating power outtages have been ordered by the authority who has power to order them (forget the name).

Normally, the province would have plenty of power. Currently, 5 of the 18 power generating stations in the province are down for one reason or another. We'd still normally be fine, except that the extra power line from BC (which provides more power when we need it) is also down due to a presumed lightning strike.

So, in a sense, Murphy's Law has struck once again.

My better half who works at the AESO tells me this is the correct reason. The line from BC did get struck.