Dear Dr Zimmerman, I decided that, for the hours that the load exceeds the minimum generation I will run a dupf.I tried it and it works fine. I was confused, because case 24ieee is a matpower case, so I had thought that it should work correctly if I don't do any modifications.But do a yearly simulation is an extention of the fixed peak load that there is in mpc.bus(:,2). Anyway! Please correct me if I am saying something wrong. Thanks for your time and help! Regards, Angelina
From: [email protected] To: [email protected] Subject: RE: negative generation on opf Date: Tue, 23 Apr 2013 19:54:09 +0300 Dear Dr Zimmerman,Thanks a lot for your help.I ran a dc opf for case 24ieee without considering any faults, for the whole year, in which the load in the buses is the one determined from ieee reliability test system with annual system peak 2850 MW and annual system min 965MW. For the hours that don't converge, I checked the sum of the load for all the buses and the PMIN and PMAX and I saw indeed what you said.For the times that the dcopf does not converge the sum of pmin for the online generators is greater than the sum of the load for that hour.So the dc opf does not converge for all the hours that the load is lower that 1040 MW, which is the sum of Pmin for all the generators.I am a bit confused!How I can solve that problem?Can I make the assumption that the dcopf is a success for those cases?How can I control the generators , in order to have some of them shut down for those cases?Thanks for your time.Regards,Angelina From: [email protected] Subject: Re: negative generation on opf Date: Mon, 22 Apr 2013 16:31:09 -0400 To: [email protected] When the OPF does not converge, the result is often meaningless. Finding the reason for unfeasibility can be a non-trivial task. Start by checking that total fixed load lies between the sum of PMIN and the sum of PMAX for the on-line generators. Try removing all of the line flow limits. Try a simple power flow with what you think are reasonable voltage and real power set points for the generators. Once you find a feasible OPF solution you may be able to modify parameters gradually toward the infeasible case to determine which constraints bind and then conflict. Hope this helps, -- Ray ZimmermanSenior Research Associate419A Warren Hall, Cornell University, Ithaca, NY 14853phone: (607) 255-9645 On Apr 22, 2013, at 2:19 PM, angelina sirri <[email protected]> wrote: Dear Dr Zimmerman, I am doing reliability study in case24_ieee_rts and I have put extra expensive generators in load buses, in order to calculate the load curtailment.I did acopf but for some hours opf did not converged and I saw that the Qmin and max limits were violated.I couldn't find why, So I tried to do dcopf and now, it does not converges again and I see that the extra generators that I have put, some hours generate negative power of small value (like -0,0025).Have you got any idea why is this happening or what should I check?? Regards, Angelina
