“How would they get the large step down transformer they’d need to do that?”
I think too many people on here are getting their panties in a wad over really nothing.
We may very well have societal breakdown in this country at some point, but it won’t be because of some North Korean toy nuke.
As for the transformers you speak of, the ones we have here export our hydro power to the west coast. Their not necessary for our local electrical consumption. Our water, sewage and gas would be up and running quickly.
Is your local power the hydro one? Is it connected to those long power transport lines? It’s vulnerable. It will probably burn down.
As I said before, your region might come out better than most. As long as you don’t need antibiotics (manufactured overseas, come in through ports in the destroyed cities), medical equipment (MRI, CAT, etc), chemotherapy or specialized medical treatment. Or replacement parts for that electrical plant, assuming it continues to operate. Or replacement parts for any other critical equipment.
It might be a long time before those show up.