This is an area about which I know almost nothing, but I do have one
piece of information that may or may not be relevant, a memory
triggered by the comments that the generators are not phase-locked.
When I first finished navy flight training, my assignment was to a
squadron flying Constellations. These aircraft had a 400 Hz ac
electrical system. It was powered by a an alternator on each of the
four engines. To insure frequency matching, each alternator was
driven through a constant speed transmission. On engine startup the
alternators were not brought on line until they were up to speed. All
this was done by the flight engineer and I never had to actually do
it. But my recollection (which could easily be faulty since this was
45 years ago) was that the process of bringing the alternators on
line was tricky since they had to be phase-locked, or the electronics
on board would go haywire.
If my memory is correct, and phase-locking in this admittedly small
system was important, why isn't it important in the large scale power
grid?
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