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    Jimmie84 New Member

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    [ame=http://www.youtube.com/watch?v=CqEccgR0q-o&feature=related]YouTube - A Vestas wind system fail and crashes.[/ame]

    Shouldn't they have some sort of a clutch/brake system in the event the blades spin faster than originally designed?
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    donee New Member

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    Hi Jimmie,

    I believe they have a system which turns the blades out of the wind. The larger ones may also have a prop-pitch system. I read somewhere that they even modulate pitch versus rotation on some high end turbines. As the airspeed is different closer to the ground then over the top.

    Its hard to say how big this one was, but it appears to be a smaller, older wind turbine.
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    patsparks An Aussie perspective

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    I expect this unit was being tested to destruction at the end of its life by having the safety systems disabled. That's why it was being recorded on video.
    The way it was spinning was way over speed. They do have safety brakes in case the control system fails. To spin that fast, looked about 3 times normal speed, and would require 2 or 3 systems to fail. It's good to see how fast they have to spin to fail, the safety margin for normal operation must be huge.

    Thanks Jimmie, your past record of being a greenhouse denialist made me think this post would be negative toward wind turbines but it seems you have turned over a new leaf. Congratulations on waking up.
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    qbee42 My other car is a boat

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    Speed on a large wind turbine is controlled by the generator in the hub, which is really a synchronous alternator. The blades always revolve at the same speed, which is controlled by the line frequency. As the wind increases, the amount of power being generated increases. Think of it as regenerative braking: as the wind speed increases it is like going down a steeper hill - you press harder on the brake pedal. The car goes no faster, but more energy is regenerated.

    At some point increasing wind speed exceeds the safe limits for the device, at which point the blades are feathered and mechanical brakes are applied.

    Tom
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    patsparks An Aussie perspective

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    Great so see them being tested well beyond design RPM hey Tom?
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    qbee42 My other car is a boat

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    Yes, very interesting footage. You can see the initial failure, at which point the whole unit goes out of balance and falls apart.

    I am actually surprised and impressed that it could withstand so much over-speed before failure. The safety margins must be quite large.

    Tom
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    EJFB1029 New Member

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    A Vesta wind turbine collapse during a storm in Denmark. The braking system failed while two technicians worked in the turret at the top. The technicians were able to get out before the collapse. A 19 meter piece of the blade was thrown 20 metres away; Smaller pieces were sent more than 500 meters away.

    Vestas Wind Turbine Explodes With Power Earth2Tech

    While the quixotic video was fodder for YouTubers, it has not been so for the turbine manufacturer, Vestas Wind Systems. The self-destructing turbine was in Hornslet, Denmark, and apparently is the second Vestas turbine to go kaput there recently. Now the Danish climate minister, Connie Hedegaard, is investigating, according to The Copenhagen Post.

    “We’ve still got about 35,000 wind turbines across the globe that are operating fine,†Peter Wenzel Kruse, Vestas’ spokesperson, told the Post. But there is some cause for concern — two Vestas turbines in the UK collapsed late last year, which prompted the company to issue a press release announcing a joint investigation into the matter with the UK Health and Safety Executive. So that’s two separate federal inquiries in two months in two countries? Something rotten?

    Vestas is one of the largest and oldest players in the wind business, with 14,500 employees and 29 years of experience. Vestas’ web site boasts: “We install an average of one wind turbine every five hours, twenty-four hours a day.†With 4,232 MW of turbines in the U.S., the company says its turbines make up about a quarter of the total installed capacity. So these four recent failures represent only .01 percent of Vestas’s installed turbines.

    Reliability rates of wind turbines have already been the subject of several research papers. And the Industrial Wind Action Group, which “was formed to counteract the misleading information promulgated by the wind energy industry,†has archived 35 instances of wind turbine failures over the last two years.

    As bigger turbines are installed across the globe, and more of them, we’re certainly going to see bigger — and more — wind-powered failures. Startups are busy working on designs with less moving parts and a higher degree of safety, but some degree of faulty turbines are inevitable. And no amount of research and statistics is nearly as spectacular as 40 seconds of destructive YouTube-fodder.
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    patsparks An Aussie perspective

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    Someone had to spoil the fun
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    hyo silver Awaaaaay

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    Interesting, but pretty tame compared to say...Chernobyl. The cleanup should be a few decades quicker, too.
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    jayman Senior Member

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    Any proper investigation will consider Failure Mode Analysis, eg Failure Mode Effect Criticality Analysis, Damage Mode Effect Criticality Analysis, etc.

    Are the failures rare? Yes, of course. Do they make good YouTube fodder for simple minds? Yes, of course. Will this YouTube video convince simpletons that wind power is very dangerous and bad for you? Yes, of course

    Have you ever seen the aftermath of a large industrial or powerplant turbine failure? How about a high pressure steam header crack? Very spectacular and usually fatal to anybody nearby

    I could care less if electricity is produced by coal, oil, natural gas, hydroelectric, solar, wind, or nuclear: there are inherent safety issues and inherent risk. Nothing on this planet is zero risk

    The risk is usually mitigated through very careful engineering, prototyping, and - sometimes - "tombstone technology." Them's the facts, folks

    Want to know what *really* uncurls my short and curlies?

    The simple and harsh fact that whether I was an intelligence officer very early in my career, or an engineer now, very few out there are willing to listen to facts, caveats, "tricky" math, etc. They cherry pick little tidbits that support their view, and ignore the rest

    I have found that easier to deal with thanks to heavy drinking
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    tripp Which it's a 'ybrid, ain't it?

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    One of the main boilers at the Apache-3 IGCC plant, currently under construction in Pueblo, CO collapsed. This boiler was over 4 stories tall! Who know how many hundreds of tonnes the thing weighs. Accidents happen. Simple as. Like Hy-o stated, the clean up is rather trivial and the degradation of the wind farms output is probably quite small due to the inherently module design of a wind farm.
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    jayman Senior Member

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    Construction accidents and even fatalities are fairly common. You can imagine what would have happened if a hidden crack had opened and nice steam gushed out. Anybody for lobster?
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    tripp Which it's a 'ybrid, ain't it?

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    Fortunately, they're nowhere near that point yet. I was chatting with an electrician who's working on this massive project and it sounds like a complete fuster cluck.
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    patsparks An Aussie perspective

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    Did you mean cluster ... oh never mind.



    How often are there people wandering around a wind farm anyway?
    and how much warning would you get while the turbine spins up to 3 or more times its normal operating speed?
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    usbseawolf2000 HSD PhD

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    Why is there an explosion on the ground (at the base) before the blades busted?
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    GrGramps Member

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    Seawolf, That was a good catch. I had not seen that until I went back for another look.

    My guess is it was a result of the initial stage of the failure where a piece separated and was thrown downward.

    Or, it was an explosive device to create the failure which would explain the "convenient photography".

    Other ideas??

    Roy
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    jayman Senior Member

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    That certainly sounds like my current project.
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    jayman Senior Member

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    Interesting. I was focused on the airborne section, not even paying attention to the ground.
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    qbee42 My other car is a boat

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    If you look at the video in slow motion, the blades are separating before the "explosion" on the ground. It appears that a small piece of blade strikes the ground at very high speed.

    Tom
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    jayman Senior Member

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    Ah. The video isn't exactly HD

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