Generator 400v output to 11kv step up transformer - need vector group confirmation

[AHSEN_MEP]

We have 1250kva two generators of CAT which is giving output of 400voltage . These genset will be connected to synchronizing panel. After Sync Panel we will connect it with 2500KVA step up transformer .4/11kv .
This transformer will convert voltage into 11kv . vector group of this transformer is YNd 11 so primary side of transformer has three busing and secondary side has four bushings . neutral bushing will be grounded and generator neutral will also be grounded .
i need to know that this vector group is ok and will work or we need to change vector group .
secondly please confirm that as there is no neutral at primary/LV side so there will be no neutral in synchronizing panel and ACB breakers will be three pole
below link is data sheet of transformer
[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1673704708/tips/2500_11_0.4_YNd_11_irh1ew.pdf[/url]

 

[Kiribanda]

In my opinion, given transformer vector group (YNd11) is acceptable so that your 11kV system is almost effectively grounded.
But your 400V side is ungrounded which I donot think is correct.
Are your 400V side electrical equipment such as VTs, SAs are rated for an ungrounded system?
What is the reason for not connecting the generator neutral either solid or impedance grounded at 400V side?
Therefore, my advice is to implement a NGR or solid grounded system for 400V side and engineer a coordinated GF protection scheme
for the 400V system.

 

[AHSEN_MEP]

thank you for ur support ,
We will ground the neutral of generators , 2 x earth pits with 20mm x 3mtrs copper rod with grounding enhancement furse - cement for each generator Neutral . Generator body will be seperately grounded through seperate earth pit .will it ne enough . please guide .
shall we still need NGR if yes then advise the rating of NGR

 

[Palletjack]

Understand also you can inadvertently change the vector group by wiring the generator outputs to the secondary side of the step up transformer simply by connecting it with the wrong rotation.
so connecting it ABC X1,X2,X3 will be YNd11, connecting it ACB X1, X2, X3 will result in YNd1