If you tried to put a ground on that transformer on the right on X2, your high side fuse would blow imediatly!
Alot of linemen have dificulty with delta primary and secondaries. I've worked with them my whole carreer so it kinda comes easy for me. The thing to remember with a delta.... is that a delta can take one ground. It dosen't matter where the ground is as long as only one ground exists. That ground on X2, thats on the transformer to the left, mearly helps to give the bank secondary a refrence to ground and help the fuses clear in case of a fault on the secondary side.