This planet was the site of a Federation colony in the mid-24th century. In 2370, the planet changed governments to the Cardassian Union when it was located on the Cardassian side of the Demilitarized Zone after the Federation-Cardassian Treaty.
William Samuels, a farmer, and his wife Louise Samuels resided at the colony in the mid-24th century. William Samuels was a farmer there from 2350 until 2370 when he left the planet for Deep Space 9 to take part in a Maquis plot to bomb the Bok'Nor. (DS9: "The Maquis, Part I")
This planet was only mentioned in dialogue.
According to the script, the pronunciation for Volan was "VOE-lahn". 
According to Star Trek: Star Charts (p. 47) and the Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Volan system was located in the Alpha Quadrant. The system's primary was a M-class star.