The closest I've found is this:
You can increase the time that it takes for sectors to go into sleep mode by changing the file: server.ini in Users\username\AppData\Roaming\Avorion
Look for sectorUpdateTimeLimit and set it to the number of seconds you want sectors to stay awake after the last player leaves. Will probably cause immense lag if you explore a lot or if you play with a lot of other players.
eg. sectorUpdateTimeLimit=3000