Hi Thomas, It's always nice to have such a clear description of the problem you are trying to solve for questions like this. Unfortunately, I can't think of a way that MATPOWER's runopf function can solve the second part of your problem exactly as stated. The issue is that the losses and reactive power exchanges are non-linear functions of the optimization variables, so the problem does not fit the generalized form of the extensible OPF, with it's user-defined variables, constraints and costs.
I'm not sure if there is a way to use some sort of linear approximations. I couldn't think of a way to do it. -- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Feb 26, 2010, at 10:09 AM, <[email protected]<mailto:[email protected]>> <[email protected]<mailto:[email protected]>> wrote: Dear all I’m working on an optimization problem. The power grid contains about 520 branches, 390 buses and 50 generators. Now here is the problem: The following magnitudes are to be minimized: * The active power losses in part of the grid (in about 300 branches). Ploss of each of these 300 branches contributes ($/MW) to the overall costs. * The reactive power exchange at certain branches (at about 15 branches) is to be kept below a threshold (below 50% of the active power exchange Pexch). Qexch also contributes to the overall costs in $/MVar but only for the amount that exceeds the threshold (if Pexch = 10MW and Qexch = 7MVar, we pay only for 2 MVar). For this task, we have the following options: * We can change the tap settings of transformers in order to distribute the reactive power among these 15 branches. * We can use some of the generators to produce reactive power. Now here is my approach: I will use some sort of trial and error to find “good” transformer tap settings and afterwards do the “fine tuning” by changing the Qgen of the mentioned generators. Here is my question: Can I use the runopf-function to get an optimal solution for the second part of the above optimization problem, i.e. the triggering of Qgen? Looking forward to some constructive answers. Cheers in advance Thomas
