OK so I read most of this thread. We have the exact situation for one of our clients. The breaker will trip when going from generator back to utility. It will be a series coordinated fault, tripping breakers straight down the line (3) 225A breakers. There's a transformer at the end at 75kva. We adjusted the instantaneous setting and the problem went away. We felt the problem was due to asymmetrical fault inrush current because it would depend on where in the sine wave it was switched over. This site is also customer owned including transformers upstream.
VFD's wont start a motor already spinning unless they have "on the fly starting" abilities and is enabled, for similar reasons.
hence 'fire alarm booster panel'
I do not see 'fire alarm booster panel' on your pnl schedules, only 'fire alarm control panel' and 'fa power suply'
imo the breakers are set too low and are of the wrong type, no toc element (is that even code compliant for this application?)
perhaps fire alarm, elevator and emergency ltg may be exempt if desired from oc protection? (only need sc)
swap them out for I/t and your problems will disappear and you will have better protection (I think you can leave the main, just crank it up to 800%/1600 A)
Last edited by Ingenieur; 03-20-17 at 11:43 AM.
Just because you can, doesn't mean you should.
We call them "NAC panels" here.