Wind power has not turned out to be as useful a way of generating electricity as was hoped.
Only a few locales have a constant wind. Most places just have an intermittent breeze, making wind power a sometimes thing.
I see a few locations in our area with a huge wind turbine. Several stories high. Had to be expensive. Maybe the idea was to sell juice to the electric company.
However I seem to recall the propellers being stationary most times I see them.
Are they hooked up to the grid? If so then a lot of expensive equipment was installed to NOT sell juice to the electric company. I have a hunch they end up being too much expense to maintain.
Hence it doesn't seem likely that wind turbines will become so numerous as to affect grid voltage much.
And even if there are a lot, and if they're all hooked up to sell juice to the electric company... and if a windy day comes along to set them all spinning... it will usually develop over the space of a few hours... so the electric company will have time to ramp down their other methods of generation, so that grid voltage doesn't soar.
I suppose you're aware power plants are in the habit of firing up extra generators during times of daily peak demand. Then shutting them down as demand tapers off.
The above is not meant to ignore the fact that, in case of blackout, a wind turbine may be just the thing to provide sufficient power to get through a crisis.