It is not going to take anything approaching 6 months to get the grid up and running.
It is likely to trip off over  areas directly under the blast.
As the slant range increase the pulse will have lost significant energy density as it spreads.
Very little actual damage between fuses and breakers tripped will occur.

The lightning arrestors are bullet proof passive devices that can dissipate or clamp the voltage fast enough to prevent significant damage.

Fuses or circuit breakers are on the primary side of every transformer.
They will blow before excess current can damage the transformer.
It takes time for excess current to heat transformer windings.
The fuse is a designed in weak spot for excess current.