Have a look at this old thread- Lumia describs Ketevan as one of the many Georgian names which derive from Iranian (Persian) names. She cites "Katâyûn" as the original form. Cleveland Evans defines Katayun as a Persian name which means "learned." If this is correct, Ketevan is not a permutation of Katherine.
http://www.behindthename.com/bb/arcview.php?id=452914&board=gen
Hope this helps!