And do not forget that your problem might be a nonconvex one. I am afraid this one is such a one. José Luis
________________________________ De: [email protected] [[email protected]] en nombre de Ray Zimmerman [[email protected]] Enviado: miércoles, 21 de enero de 2015 16:02 Para: MATPOWER discussion forum Asunto: Re: Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. Also, for the OPF problems you may want to try a different solver if you have any available. The default MIPS solver is not always the most robust. Another thing to look for is branches with extremely small reactances, which can cause numerical problems. If the reactance is small enough, it makes sense to just merge the buses and eliminate the branch. Ray On Jan 20, 2015, at 5:27 PM, Abhyankar, Shrirang G. <[email protected]<mailto:[email protected]>> wrote: http://www.pserc.cornell.edu//matpower/#pfconvergence On Jan 20, 2015, at 2:47 PM, "Jorge Fernando Gutiérrez Gómez" <[email protected]<mailto:[email protected]>> wrote: Dear Mr. Uzbekov, I think that your case could be an ill-conditioned or an unsolvable one. In power system problems that means that: * Its loading level is close its maximum loading point or beyond it (in this case it is unsolvable). * Maybe you are using a poor initial guess. That situation could lead a standard solver (as Newton-Raphson) to a trajectory that diverges. This occurs although actually there is a feasible operating point. Best regards, On Tue, Jan 20, 2015 at 2:48 PM, Artur Uzbekov <[email protected]<mailto:[email protected]>> wrote: Dear Mr. Zimmerman, Or anyone who can help me. I am trying to run a model of a big grid in Matpower. It has 130 loads, 329 generators and 286 branches. I obtain an optimal solution for DC Power Flow problem which is most probably correct (it corresponds to the real data). But For AC Power Flow and both DC and AC OPF problems, I get the following message: Warning: Matrix is close to singular or badly scaled. Results may be inaccurate. And the success flag is 0. I have checked that the are no islands in the network. In some forums people write that it could happen due to the bad modelling or too heavy loads. But for me this explanation is not clear. Can you please comment on that or suggest any other explanation. Looking forward to hear from you! Arthur -- Jorge Fernando ============================================================== Por favor, piense en el medio ambiente antes de imprimir este mensaje. 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