Thanks a lot for your answers...yes I got my answer...but I found it complicated to write the hessian function for my objective and constraint functions according to that in matpower. I would like to get answer and possibly add it to matpower to handle the distribution OPF as well. best regards bv
On Wed, Jun 2, 2010 at 4:22 PM, Ray Zimmerman <[email protected]> wrote: > The power balance equations are included explicitly as equality > constraints. See equation A.2 in the manual. They are not handled by solving > a separate load flow problem. The latest version 4.0b4 includes a > "constrained 4-d non-linear" test problem in t/t_mips.m that includes a > non-linear equality constraint. > > I'm not sure if this answers your question. > > -- > Ray Zimmerman > Senior Research Associate > 211 Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > On Jun 1, 2010, at 5:47 PM, b v wrote: > > Hello, > Thank you...yes I had a look at this and also solved an easy optimization > problem like those in t-mips.m using mips solver successfully. But by > comparing my OPF distribution problem with those in t-mips.m, I face with > some difficulties. As you know the equality constraints in OPF are the load > flow power balance equations which first should be solved by ac load > flow. How can I handle with the load flow part? > Many Thanks in advance. > Best Regards > On Tue, Jun 1, 2010 at 1:41 PM, Ray Zimmerman <[email protected]> wrote: > >> Have you looked at the examples in Appendix A in the MATPOWER User's >> Manual <http://www.pserc.cornell.edu/matpower/manual.pdf>? You can also >> find a few more examples in t/t_mips.m. It sounds like you have already >> implemented the objective function and constraint evaluation function for >> you problem, which includes the gradients. So, the only thing missing is a >> function for efficiently evaluating the Hessian of the Lagrangian function >> for your problem. The opf_hessian function computes this for MATPOWER's >> OPF and the derivation of the formulas used can be found in the MATPOWER >> Technical Note 2, AC Power Flows, Generalized OPF Costs and their >> Derivatives using Complex Matrix >> Notation<http://www.pserc.cornell.edu/matpower/TN2-OPF-Derivatives.pdf>. >> You may find it helpful in the derivation of the Hessian for your problem. >> >> Feel free to ask if you have specific implementation questions. >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> On May 31, 2010, at 5:45 PM, b v wrote: >> >> Hello all, >> I have a project to do OPF for distribution systems. The objective >> function is to minimizing the Power loss. I have done it already by MATLAB >> using fmincon function. >> However, for using *mips* solver in Matpower and taking the hessian >> matrix from the *opf_hessfcn* function I would like to do it in Matpower >> too. But I do not have any idea how to do it and if it is possible at all. >> If it works then we can use the matpower for doing OPF in distribution >> systems as well. >> Can anyone please explain me simply how I can use Matpower to optimize *my >> own objective function* respect to *my own constraint*. I should add that >> my data file is exactly same as casedata format in Matpower and just the >> obj. function and constraints are different. >> Many Thanks in advance. >> Best Regards >> >> >> > >
