News Damn this day...(Suicide attack and power plant disaster)

[SiberianTiger]

Damn this day...

At least 19 people have been killed by a powerful bomb at a police station in southern Russia, officials and hospital sources say.

The suspected suicide attack in Nazran, the main city in the republic of Ingushetia, injured more than 60, including some children.

http://news.bbc.co.uk/2/hi/europe/8204670.stm

At least 54 people are missing after an explosion at Russia's largest hydro-electric power station killed eight workers, investigators say.


The accident at the Sayano-Shushenskaya power station in Siberia happened when an oil-filled transformer exploded in a turbine hall, they added.

http://news.bbc.co.uk/2/hi/europe/8204860.stm

YouTube - AMV-Look out for yourself! (News summary for tommorow)

Today somebody's saying See you later,
Tomorrow will say... Good Bye forever,
The heartache will begin,
Tomorrow someone coming back home,
Will find their cities in ruins,
Someone will fall off of a crane,
Watch yourself, be careful.
Watch yourself.

Tomorrow someone laying in bed will,
Realize their sickness has no known cure,
Someone leaving their house will get hit by a car,
Tomorrow somewhere in one of the hospitals,
The hand of a young surgeon will falter,
Someone will step on a mine in the woods,
Watch yourself. Be careful.
Watch yourself.

Last night a plane flew over our heads,
Tomorrow it will crash in the ocean,
All the passengers will meet their deaths,
Tomorrow somewhere, noone knows where,
War, epidemic, snow blizzard,
Outer space's black holes...
Watch yourself. Be careful.
Watch yourself. Be careful.
Watch yourself. Watch yourself.

---------- Post added at 17:31 ---------- Previous post was at 17:00 ----------

Couple of videos of the destroyed power plant's building

YouTube - Ð�вариÑ� на СаÑ�но ШушенÑ�кой ГÐ*С

YouTube - Ð�вариÑ� на СаÑ�но ШушенÑ�кой ГÐ*С

 

[Urwumpe]

Yay... the explosion of the transformer looks really really nasty. I know that transformers can unleash a lot of power and create extreme fires, but explosions had been new to me.

 

[SiberianTiger]

Yay... the explosion of the transformer looks really really nasty. I know that transformers can unleash a lot of power and create extreme fires, but explosions had been new to me.

Officials now say that the most probable cause of the generator building flooding was breaking through of a turbine cover because of extreme turbine's wear out.

As of now, 14 people are confirmed dead, 15 are injured and 63 are still missing. 2 people were rescued last night from an air pocket inside the flooded building.

 

[Urwumpe]

Officials now say that the most probable cause of the generator building flooding was breaking through of a turbine cover because of extreme turbine's wear out.

Also possible in that order, most visible damage is caused by the flooding, but either a broken turbine blade or a strange massive transformer explosion should be able to lift the turbine cover away...

Still... is maintenance of the infrastructure in Russia still so bad that you can't replace turbines when cavitation wears them out? There should have been some clear warning signs before a turbine breaks, like a strong loss of effectivity.

(Edit: Before somebody exposes it: I have no clue on hydropower turbines. I know turbines for rocket engines and I know the similar erosion effects on ship propellers, since I have a strange unnatural interest in ship theory...I just deduct from the things I know to other things)

 

[SiberianTiger]

Still... is maintenance of the infrastructure in Russia still so bad that you can't replace turbines when cavitation wears them out? There should have been some clear warning signs before a turbine breaks, like a strong loss of effectivity.

This is what's the entire Russian blog space is buzzing about now. RosHydroEnergo say it will take them months to discover the real cause of the accident, and right now they are concentrating on rescue operations.

Meanwhile, electricity tariffs are already rocketing up in Siberia.

Not sure it was a cavitation-induced damage, though. If, say, a blade falls off, would it make the shaft break though the cover?

 

[Urwumpe]

Not sure it was a cavitation-induced damage, though. If, say, a blade falls off, would it make the shaft break though the cover?

I have seen far worse damage in lower scales, when a cheap, too small and soft metal bolt from a Volkswagen gear box dropped between the gears and blocked the bearings with metal debris while driving at 150 km/h - it literally exploded the gearbox and dislodged many shafts.

The stored rotational energy inside the turbine is extreme (A few tons mass and up to about 3000 rpm), and if you just change the moments of inertia a tiny bit, for example by breaking away a turbine blade, you can experience first hand what transfer of momentum means. In pure theory, you could have the turbine in one short instant tilt the rotation axis by 90°. The turbine would not only leave the turbine housing, but also get out for a long walk.

 

[SiberianTiger]

The stored rotational energy inside the turbine is extreme (A few tons mass and up to about 3000 rpm), and if you just change the moments of inertia a tiny bit, for example by breaking away a turbine blade, you can experience first hand what transfer of momentum means. In pure theory, you could have the turbine in one short instant tilt the rotation axis by 90°. The turbine would not only leave the turbine housing, but also get out for a long walk.

http://www.sshges.rushydro.ru/hpp/units/hydro

The turbine's picture:

Diameter: 6.77 m
Mass: 156 tonnes
16 cavitation-resistant blades
Water throughput: 358.5 m^3/s
RPM: 142.8
Working pressure: 63 MPa

(does it worth to have a separate thread for the Hydro plant accident)?

 

[Urwumpe]

Diameter: 6.77 m
Mass: 156 tonnes
16 cavitation-resistant blades
Water throughput: 358.5 m^3/s
RPM: 142.8
Working pressure: 63 MPa

OK, is operating at a lower speed than I expected (I just took the desired frequency of the AC), but still... 142.8 rpm at 156 tons are at least 8.398 Gigajoule energy (PMI around the rotation axis = 1.0)

(does it worth to have a separate thread for the Hydro plant accident)?

I'd suggest yes. It is a completely unrelated event...maybe

 

[ijuin]

Still... is maintenance of the infrastructure in Russia still so bad that you can't replace turbines when cavitation wears them out? There should have been some clear warning signs before a turbine breaks, like a strong loss of effectivity.

My understanding is that there isn't enough excess generator capacity in the power grid--so taking the generators off-line for long enough to perform maintenance work would result in brownouts because there is nothing else to take the generating load. As a result, not only do they get disasters like this, but the engineers are kept so busy cleaning up after them that they have no time to build additional new power plants even if there was money to build them.

 

[SiberianTiger]

The strange thing, however, that there really was no apparent signs of a nearing disaster. Looking in the blog of the guy who is a power engineer regularly working at Sayano-Shushenskaya Plant, I can see pictures of the now destroyed machinery, taken on the past week. They don't look like treated without care:

Scary to imagine what it was like when the thing like this virtually exploded under water pressure:

And they did have automatic process monitors:

His own cautious guess is that it was either a hidden defect in the turbine itself, or the machinery was miscontrolled one way or another (perhaps kept for too long in a state of transition).

 

[Urwumpe]

What does the bar plot in the lower center right show, right next to the turbine? What surprises me: The control fins for the felton turbine are not shown in the diagram (aside as a graphic in the turbine). You have inlet and suction tube pressure (20 bar/0.6 bar), but no indicator for how the control fins are set. I also miss a calculated mass flow through the turbine, which would be helpful together with the turbine rpm and the pressure drop in the turbine, how effective the turbine currently is.

Also, what do the two percentages above the bar plot show? 100.10% is either a calculation error or the turbine is operating beyond design limits.

 

[SiberianTiger]

What does the bar plot in the lower center right show, right next to the turbine?

The title says: positions of servo-motors.

What surprises me: The control fins for the felton turbine are not shown in the diagram (aside as a graphic in the turbine). You have inlet and suction tube pressure (20 bar/0.6 bar), but no indicator for how the control fins are set.

See below.

I also miss a calculated mass flow through the turbine, which would be helpful together with the turbine rpm and the pressure drop in the turbine, how effective the turbine currently is.

Maybe it's on another control screen?

Also, what do the two percentages above the bar plot show? 100.10% is either a calculation error or the turbine is operating beyond design limits.

77.6% is Wicket Gate Opening (the same things as control fins position?)
100.10% is RPM Rate

Maybe it really was off some preset limits when the screenshot was taken, but it was turbine #2 that broke, not #6 anyway.

---------- Post added at 20:06 ---------- Previous post was at 19:56 ----------

BTW... The guy's blog has just been deleted. The picture links are still alive, but if you want to keep them, better save locally.

 

[Urwumpe]

Yes, would be the control fins (I can't even translate the little knowledge I have of the stuff in German properly into English, so don't worry).

Both numbers are not too strange, but the opening of the control fins/gates/what ever is a function of pressure - AFAIR, the reservior of the power plant had higher water levels currently, so the pressure was slightly higher than normal, which would mean that less opening of the control fins relates to full turbine power already.

What I know of this power plant, it was operated at peak capacity most of the time, except during the summer months.

 

[Andy44]

That's scary. I've been to several dams, including Hoover Dam. The turbine room was throbbing with energy. Gigantic penstock pipes 30 feet in diameter feeding the turbines. I can'r imagine the hell breaking loose in an accident like that.

 

[SiberianTiger]

That's scary. I've been to several dams, including Hoover Dam. The turbine room was throbbing with energy. Gigantic penstock pipes 30 feet in diameter feeding the turbines. I can'r imagine the hell breaking loose in an accident like that.

This picture helps to imagine the scale of the thing:

 

[Andy44]

I've also been to the bottom of Kinzua Dam in Pennsylvania when it was doing this:

This is fairly large dam in northwest Pennsylvania on the Allegheny River. The water blasting out of those gates is from the bottom of the lake behind the dam, and there are two more gates near the top which were also open when I stood at the railing visible in the bottom of the photo. The noise and thunder was awesome (the actual definition of the word: inspiring awe). Imagine being in a room with a geyser of water under that sort of pressure coming in.

 

[Urwumpe]

Does somebody have a link to the video of the first seconds of the accident? I have seen it in TV news last night, but can't find it on youtube myself. You can see the water shooting out of the turbine building there.

 

[Artlav]

Does somebody have a link to the video of the first seconds of the accident? I have seen it in TV news last night, but can't find it on youtube myself. You can see the water shooting out of the turbine building there.

You mean this one?

And, consequences:

 

[Urwumpe]

Yeah, that is the one.

 

[Andy44]

Wow, that is one scary video. I don't speak Russian, was that guy laughing at it? I am guessing he didn't understand what he was witnessing?