Does anyone have any input as to how the systems on the Airbus (OR Boeing for that matter) tolerate such a power spike, or what happens if they don't tolerate it?
Not familiar with Airbus systems but possibly not dissimilar to B747 Electrical systems.
The main generator voltage output is controlled by a regulator contained in the individual generator control units.
A sensing circuit continually measures the generator output voltage and informs the regulator as to how much energy should be applied to the generator field to maintain the proper output.
Excitation faults, generator differential faults, open phase faults, difference current faults, speed faults, synch bus faults will activate appropriate actions to protect associated load circuits.