Hej all, I am modeling blackout in the US transmission lines system, and have two approaches to do so. I do it with DC power flow, which means I don't need to take care of islanding if I don't want to (although I am aware that I need to take care of isolated buses for convergence reasons). I have two approaches to do so: (1) do cascading failure simulation on whole system each iteration, whereby one doesn't keep track of islands; (2) do cascading failure simulation on the whole system to begin, see if islands are formed, and run the same simulation on each of these islands, and repeat the process exhaustively. In both cases, the powerflow converges as it is DC flow. However, the results are not matching, and I am wondering why. Could it be because of the difference in the number of slack buses? Because in my approach (1) the system will only have one slack bus in each iteration, however in my approach (2) the system will have multiple slack buses as the matpower chooses slack buses for each island automatically, thereby my system as a whole will have multiple slack buses. Is this the only reason? Which approach is better, (1) or (2)?
Best, BH
