The possible reasons could be;

(1)- to use a delta-wye transformer to trap the triplen harmonics,

(2)- One obvious reason for stepping up the generated voltage level to higher transmission/distribution level to reduce losses in transmission.

(3)- Inductance of the transformer also acts as passive inductive filter.

thank you.

Also work as electric isolating (transformer) between grid and inverter, to protect from transient surges ,

The main reason for using Transformers on AC side is to decrease losses on transmittion's line and to protect the loads.

TX is mainly for step up for sync purposes with the grid.

Many reasons some are

to step up voltages on the grid side

to get rid of the third harmonic wth wye-delta transformer

to reduce losses but this quisionable

to isolate inverter from transients of the grid