I’m afraid I don’t understand. I thought the issue was that the total power output of the generators *does* change between the two cases and you thought it should be the same.
At this point, though I may be wrong, I think your questions relate to power flow and OPF in general and not to MATPOWER usage specifically, so may I suggest you find a local power systems expert or another forum to help you sort through it. Best regards, -- Ray Zimmerman Senior Research Associate B30 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jan 8, 2014, at 10:49 AM, Carlos Gonzalez Almeida <[email protected]> wrote: > My main problem is that with and without changing voltage at slack bus the > total out power of generators don't change. How can I solve it? > > Best regards, > > > > Best Wishes > > > > > On Wed, Jan 8, 2014 at 3:14 PM, Carlos Gonzalez Almeida > <[email protected]> wrote: > Thank you. What corrections I have to apply to the abovementioned code in > order to obtain true results? > > Best regards, > > > Best Wishes > > > > > On Tue, Jan 7, 2014 at 1:57 PM, Ray Zimmerman <[email protected]> wrote: > I believe both of your questions have the same answer: When you allow more > flexibility in the system (increased range of generator voltages or variable > power factor) there are more degrees of freedom to use to reduce costs. In > particular, there is more flexibility that can be used to minimize losses, > resulting in a decrease in overall generator output. > > -- > Ray Zimmerman > Senior Research Associate > B30 Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > On Jan 7, 2014, at 5:59 AM, Carlos Gonzalez Almeida > <[email protected]> wrote: > >> Dear Dr. Zimmerman, >> >> When I am running an OPF considering two cases; >> >> 1) Fixed power factor >> 2) variable power factor >> >> in (1) the total output power of generators are higher than that obtained in >> (2). But It should be vice versa conceptually, i.e. it should be higher in >> case (2). Could you please let me know what is the reason? >> >> The following codes have been used to obtain the results. >> >> (1) >> >> define_constants; >> mpc = loadcase('case9'); >> nb = size(mpc.bus, 1); >> ng = size(mpc.gen, 1); >> pf = 0.85; >> QPratio = sqrt(1/pf^2 -1); >> %% add constraint that QPratio * Pg(i) - Qg(i) = 0, for i = 2 .. ng >> mpc.A = sparse([1:ng 1:ng]', [2*nb+(1:ng) 2*nb+ng+(1:ng)]', >> [QPratio*ones(ng,1); -ones(ng,1)], ng, 2*nb+2*ng); >> mpc.A = mpc.A(2:end, :); >> mpc.l = zeros(ng-1, 1); >> mpc.u = mpc.l; >> r = runopf(mpc); >> ************************************************** >> >> (2) >> >> define_constants; >> mpc = loadcase('case9'); >> r = runopf(mpc); >> **************************************** >> >> According to abovementioned codes >> >> >> Best regards, >> > > >
