Hi ,
>Is the PVT the Operation Condition?
Yes. This is correct
>Is the OCV the variations on a given PVT?
Yes. This is right. IT may be a process, voltage and temperature
>Is the Corner and OCV the same?
No. This is not correct. Corners are extraction corners. During fabrication, due to process variation, a wire may have diffrent R and C. To cover these foundry will give various corner nxtgrd files.
Using these we have to extract the design in suggested corners and close the timing.