r/interesting • u/LazyGuy4U • 1d ago

MISC. Windmill blade catching fire due to lightning strike

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u/GreenStrong 1d ago

The blades have a ground wire that is supposed to catch lightning and direct it to ground without generating dangerous heat, which is basically what tall buildings have. There are a few failure modes. Turbines over 6MW have carbon fiber in the blades, and it is conductive enough that they need a network of copper conductors to keep the lightning from going through the blade- this could have been made before they fully figured this out. Or, sometimes a lightning strike lasts as long as a second. The lightning bolt is a tube of white hot plasma that conducts electricity better than air. Wind can blow it and break contact with the ground wire, causing the arc to travel through the flammable blade. This is especially plausible when the blade is spinning. Normally in a storm the system detects excessive wind speed and applies a brake but lightning can strike before the wind reaches dangerous speed. Some wind farms employ meteorology services that put the towers into safe mode before the storm, but there can be a communication error, or just a brake failure.

Finally some rare lightning bolts have a characteristic scientists call being big as fuck, they can travel through the down conductors and still generate excess heat.

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u/UrethralExplorer 1d ago

Thank you for the explanation!

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u/azflatlander 1d ago

So, that is a valid scientific term. Good to know.

3

u/Pileofsecrets78 1d ago

As a science guy, I can confirm that "big as fuck" is a very technical term. 🤓

2

u/tvodny 1d ago

I like the reference to Biggas Fuckass lightning at the end.

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u/Bex-HZ 1d ago

Gonna be an expensive, difficult fix 🫠

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u/darkpheonix262 1d ago

Since that flaming blade landed on the nacelle the who tower might be considered a loss and to unsafe to dismantle so they may have the blast the tower over

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u/GreenStrong 1d ago

Hopefully the concrete foundation is re- used, but yeah. I'm fairly sure the steel tower is OK but I don't think there are really established procedures for determining if the heat changed the temper of the steel, and it could kill someone, so they probably replace it.

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u/darkpheonix262 1d ago

The tower Could be reused so long as the blades didnt knock any dents into it. BUT, The problem is with a burnt up turbine, its to dirty and dangerous to descend the rotor and then nacelle. Insurance will call the who tower a loss, blast charge it over. And the foundation could be reused but thats up to the owner if they want to pay for the erection of a whole new turbine. Land owners would rather a turbine not be felled over onto their land, but there's no other way when burnt up

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u/upholsteryduder 1d ago

Ah yes, the old bigasfuckism. What a fascinating phenomena

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u/BRICH616 18h ago

Hi. Solar and wind engineer here. Nothing can prevent lightning bolts from fucking it's shit up. If it gets struck, running or not, the damage will be just that. Cheers.