Tripping by Neutral Displacement Relay

The relays that are tripping protect your hardware from catastrophic damage. Proper troubleshooting will first identify the type of fault that makes this relay to trip. Next a good troubleshooter will be determine if that fault condition actually exists or if the relay is triggered by a false fault. The troubleshooter will respond accordingly.

The last thing one should do is to shout at a public forum that you do not understand how to do your job. What you really do not grasp is if you showed any comprehension of your circumstance by saying what testing you've done or even what settings your relay were at when they tripped then people here will help.

Although you have not provided the vector group for each transformer I suspect that the secondary of the unit auxilliary transformer is delta connected. If so then it was done like that to ensure continued operation in the event of the first ground fault; that's why you only get an annunciation. However if you ignore the alarm the second fault will provide some really big clues as to its location.