I am currently working on a DVR for a wind system. I have referred multiple papers but I am still unclear about the following.

1) how to design the parameters for the injection transformer (particularly for WRSG)?

2) How to design the control logic for DVR, so it comes in to play only when there is a voltage variation?

As I am new in this area of research, even basic explanations would be of great help.

Thanks in advance.