2021-08-03 at 11:08 am
#1383
Hamid
As you have mentioned, they will want to make an artificial neutral point as indicated in following diagram. Theoretical this is possible, but you must check the isolation of UPS grounding system and that artificial neutral bar. Also the auxiliary transformer must be rated for withstand phase-neutral short circuit current (equal to upstream system earth fault current) additional of normal neutral loads; it seems this point can be increased the cost of mentioned transformer very much.