It makes perfect sense! Thank you very much indeed.
All the best, Arash Alimardani University of British Columbia On Mon, Dec 16, 2013 at 8:55 AM, Ray Zimmerman <[email protected]> wrote: > This can get a bit confusing because x is in p.u., but the functions > totcost and polycost assume everything is in MW. So xx is converted to MW > to compute f. The first derivative of the cost returned by polycost in > line 135 is in $/MW and must also be converted to $/(p.u. generation). > > I hope that helps, > > -- > Ray Zimmerman > Senior Research Associate > B30 Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > On Dec 13, 2013, at 4:29 PM, Arash Alimardani <[email protected]> > wrote: > > Dear Dr. Zimmerman, > > I may be wrong, but apprently, in opf_costfnc.m, line 135, there is an > issue which it not clear to me. In calculating the gradiant of cost > function, baseMVA is multiplied as in: > df_dPgQg(ipol) = baseMVA * polycost(gencost(ipol, :), xx(ipol), 1); > > However, in calculating xx(ipol), in line 87, it has already been > considered that baseMVA should be multiplied to get actual values which are > not in per unit as: > xx = [ Pg; Qg ] * baseMVA; > > Therefore, there seem to be no reason for multiplying the gradient in line > 135 by baseMVA again, and it should be: > df_dPgQg(ipol) = polycost(gencost(ipol, :), xx(ipol), 1); > > Please, let me know of your opinion on this. > > Regards, > Arash Alimardani > > >
