So in the video I saw of a wind turbine turning so fast in a storm that it threw itself apart, it wasn't the brake that malfunctioned but the mechanism that turns the angle of the vanes?
From what I've seen and read, yeah. They use a governor on the system that as it passes a certain speed, the vanes turn to maintain that speed, up to a certain point, where the brakes would engage to halt it completely. It may have been braked and the brakes failed, all it to continue to accelerate when the governor had topped out.
I saw a windfarm on the Gaspe peninsula, and they had a few vanes lying about at the tourist stop. Very long, very substantial. but as with helicopters, the tip is moving at one hellatious clip while the centre isn't.