Hello sir... I have to calculate LMP for ieee39 bus system... How to calculate that by using matpower sir? Please help me...
On 9/24/14, Jiazi Zhang <[email protected]> wrote: > Dear Dr. Zimmerman, > > Thank you so much for your approach. But I still have several questions. > > 1. For the two dummy buses, where should I add them? Are they directly > connected to the original bus X and Y? Or they are not connected to bus X > and bus Y, but have the same buses connection as X and Y? > 2. According to step 1, the relaxed line is reconnected to bus X' and bus > Y', but in step 6, it seems the line connected to X and Y still exists. > Should both the lines connected to X and Y, and X' and Y' exist in the > system? > > Actually I'm not fully understanding why this approach can be equivalent to > relaxed the thermal limit constraints on a specific branch. Can you explain > the theory of the approach more in detail? > > Thank you! > > Best Regards, > Jiazi > > On Tue, Sep 23, 2014 at 1:20 PM, Ray Zimmerman <[email protected]> wrote: > >> There isn’t a really easy to solve what you want with the current version >> of MATPOWER, but I think it should be possible to do it with a few >> “tricks”. >> >> For a branch between bus X and bus Y ... >> >> 1. Add two dummy buses X’ and Y’ and reconnect the line to X’ and Y’ >> instead of X and Y. >> 2. Add dummy generators at X, X’, Y and Y’ with PMIN = –M, PMAX = M, >> where >> M is some value larger than the max flow on the line (even in the relaxed >> solutions). >> 3. Add user-defined linear constraints to enforce equality between the Pg >> of dummy gen at X and -Pg of dummy gen at X’, and likewise for dummy gens >> at Y and Y’. >> 4. Set the cost on each of the dummy generators to a piecewise linear >> function that is zero up to the original line limit value, and some large >> value above that. >> 5. Add user-defined linear constraints to enforce equality between the >> voltages (magnitudes and angles) at X and X’ and at Y and Y’. >> 6. Remove or relax the original line limit on the line itself. >> >> I don’t think I’ve never tried this, so I’d be interested in hearing how >> well it works if you decide to attempt it. >> >> -- >> Ray Zimmerman >> Senior Research Associate >> B30 Warren Hall, Cornell University, Ithaca, NY 14853 USA >> phone: (607) 255-9645 >> >> On Sep 23, 2014, at 5:51 AM, Jiazi Zhang <[email protected]> wrote: >> >> Dear all, >> >> >> I'm running AC OPF using Matpower for my project and for some cases, the >> OPF does not converge due to the capacities of several branches are not >> enough. >> >> I'd like to relax the thermal limit constraints on these branches with >> large penalty factors. But the power flow thermal limit constraints are >> nonlinear for AC OPF. I wonder if it is possible to do such branch limit >> relaxation in AC OPF program. >> >> >> Best Regards, >> >> Jiazi >> >> >> -- >> Jiazi Zhang >> Research Assisant >> School of Electrical, Computer & Energy Engineering >> Ira A. Fulton Schools of Engineering >> Arizona State University >> [email protected] >> >> >> > > > -- > Jiazi Zhang > Research Assisant > > School of Electrical, Computer & Energy Engineering > > Ira A. Fulton Schools of Engineering > > Arizona State University > > [email protected] > -- <http://sig.graphicsfactory.com/> Emoticons <http://sig.graphicsfactory.com/>
