The Cabral sector was a region of space. The Vaccan system was located in this isolated sector.

In 2370, the Federation starship USS Enterprise-D delivered the survivors of Boraal II to Vacca VI. (TNG: "Homeward")

According to the script, the pronunciation for Cabral was "cuh-BRAL". [1]
The Star Trek Encyclopedia (4th ed., vol. 1, p. 112) located the Cabral sector in Federation space.