If the large backbone transformers in the grid are not outfitted with fast ground fault interrupters they would be damaged and the grid for large regions would go down. There are no backup transformers waiting. It would take a few to many months to produce and install new backbone transformers even in normal times. It might take more when the grid is down. This lack of electricity would have compounding effects.
A much lesser worry is the satellites in orbit getting deep ion charging and sparking and getting damaged.