Dear MATPOWER-Community, dear Mr. Zimmerman, I would like to maximize the reactive power output from all generators in the net, one time for maximum induktive reactive power and one time for maximum kapacitive reactive power. So I use the MATPOWER-OPF with a customized piecewise linear cost function which I define in the gen_cost matrix. For example if i would like to maximize the reactive power output from all non slack generators so that they behave like an inductivity I set the data points for my cost function for all non slack generators like this: (-100 | 1000), (0 | 0), (100 | -1000)
My first question is: Does it make any difference in OPF-behavior if I change the slope oft the segments of the cost function or is it irrelevant? For example is there a difference with regard to stability or performance if I use this cost function instead of the one above: (-10 | 1000), (0 | 0), (10 | -1000) If there is any difference, how do i find the best slope for the segments of the cost function? My second question is: I can define an opposite cost function for the slack generator: (-100 | -1000), (0 | 0), (100 | 1000) Is it better to set this cost function also for the slack with regard to stability or performance or is it irrelevant? An other option would be to only set the cost function for the slack and set costs for all non slack generators to zero. Is it better with regard to stability or performance or is it irrelevant? My third question is: With a casefile with about 90 buses and about 10 generators it works great but with a casefile with about 2500 buses and about 300 generators it doesn't work anymore. With the big casefile there are some generators where the reactive power output is not maximized, though there are no voltage violations or power flow limits. Whats the reason for this behavior and is there a possibility to make it work with a big casefile? Do you have any general tips for me or is there another method to improve stability or performance? Thank you very much! Best regards Jens W.
