I would start out with a voltage that matches your machine. Vars flow from higher voltage to lower, so as you change this system voltage you should see corresponding change in var flow. Power flow is controlled predominately by phase angle. So, as you play with that you should see changes in power flow. See this link for more clues.
The link you gave in your comments above seems very explicit in detail. Including giving the values you are talking about.
To apply a short circuit you need your voltage source to go to zero (on whatever phases you want to fault, or all 3 if three-phase fault).