Mates wrote ...

I remember that we had in our country a case: A group of some crazy people calling themselves The Darkers made few successful attacks on the power lines causing a blackout in the whole city. I remember that police and also the intelligence were very active to stop these people (and were most likely successful because the whole thing disappeared very quickly). Of course I was very curies how these people could damage a power line but the way how it was done was never released to the public. I came with my own explanation which was very similar like what we can see here. My explanation was that they used a cheap fire-works rocket and hooked a piece of grounded wire to it. The only problem with this set-up was that when I asked a guy who makes the power electrics for living he told me that the wire would have to be pretty strong to cause blackout-short circuit, thus no commercial rocket could pull it there.
What we see here is definitely stupid fun, but it is still a piece of tiny wire which makes the short circuit – honestly guys you really believe that such short-circuit can cause a blackout of 500KV power line?

Dago wrote ...

Though I admit I cant say for sure, I guess its possible aswell that the wire just vaporizes and there is no arc formation.