Jim Stewart wrote:

I can't think of a worse situation than strapping
together the two busbars of generators exactly
180 out of phase. You'd be producing a fault
current twice that of a hard short circuit. If
everything were sized for that, it's no surprise
something exploded.


I can, and thats closing in one generator to a stiff system, 180 out.
You still produce a fault 2x that of the 3phse bolted fault, but that
starts out as a larger number in the stiff system case.
jk