It's my understanding that a Carrington event would destroy the bulk of the electrical grid on the side of earth facing the sun at the time. But would be pleased to hear how I'm wrong!
It depends on how much preparation the power grid in different places would have. I think the even will not be catastrophic but will cause a lot of damage and disruption. Mainly because we will lose satellite communication system and GPS systems and there will be at least localized problems with the grid system in different parts of the world.