Kelvas Prime was the inhabited prime planet in the Kelvas system.

Following the supposed demise of Damar, Mila overheard a rumor that someone's cousin had seen Damar on Kelvas Prime. (DS9: "The Dogs of War")

This planet was only mentioned in dialogue.
Since Kelvas V and the Kelvas repair facility were both Cardassian, this might have been a Cardassian planet.
According to Star Trek: Star Charts (p. 46) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Kelvas system was located in the Alpha Quadrant.
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