That's interesting. In practice a 2 MVA transformer should handle 2 MW without problems. But in your case the winding currents in the transformer seem to be significantly higher than the design value. Either the transformer isn't actually capable of 2 MVA - if this is so you have a case against the manufacturer. Or, the currents in the transformer (I assume it's 3 phase) are substantially unbalanced. Or, just possibly there are significant high frequency or harmonic components contributing current to the I2R loss which were not anticipated by the designer.

Normally 2 MVA transformer should handle 2 MW Inverter. But what about the total capacity of DC power loaded to the inverter, I mean is it up to Max. DC Input Power (W)? If DC side is loaded more than rated ( but accepted up max dc limits by inverter, normally 5% to 15%), it will give output more than Nominal Output Power (W) ? Normally it's stated as " Max. Output Power (W)" in specs. Sometimes this can be the reason.

Also, current in the transformer for a given power and power factor is

I = W / (E * cos(phi)) where W is real power and phi is the lag angle. Now, the MVA is usually rated on the basis that cos (phi) ~ 0.8; but if cos (phi)

Tony Maine Thanks for answer >>> actually the manufacturer started to measure harmonics and the reports claims no up normal things happening

What they are saying the HV winding burnt totally and if it is due to manufacturing defect it should be in one point no the whole winding …. so it is outside event resulted into insulation failure for the whole winding

Another theory from our EPC says all RIS protection devices do not sense the error properly and they are going to replace all of them !!

This shows how easily you can go deep into theory to explain something, when actually one of more of your measuring instruments is simply totally wrong and giving meaningless readings. I feel sure that if the RIS are working properly you won't get this effect at all.