"The blade of a large wind turbine move at more than 100 miles per hour"
Doesn't that depend on the speed of the wind?
They have an automatic control to vary the pitch of the blades so that they always turn the same speed.
If there is not enough wind to turn them that fast, they stop.
They must match the 60 Cycles per Second of the power line they are feeding into.
The Cycles Per Second is determined by the speed they spin.