Making Vm = 1 means that the voltage is equal to its nominal value specified in the BASE_KV column of the bus matrix.

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Regarding relaxing line limits, first this is the one case where setting them to zero is interpreted as completely unconstrained. That is a reasonable thing to try in the process of trying to get a convergent case. The question of what sort of violations of the original limits are acceptable depends of course on the particular system and scenario you are trying to analyze/optimize. Ray > On Mar 7, 2018, at 10:21 PM, Aakanksha Dubey <aad...@lehigh.edu> wrote: > > Thank You, Mirish and Shri for the guidance. > > Shri, the model is converging now. I understand that Vmax and Vmin limits > should have been more relaxed. I have a couple of quick follow-up questions: > I had set the voltage magnitudes on per unit basis since the network voltages > range from 69kV to 500kV. By now making Vm=1, wouldn't all voltages be set > equal to 500kV? > Also, while relaxing line limits, what is the maximum acceptable percentage I > should be increasing those values to? > > sincerely, > Aakanksha Dubey > > > On Wed, Mar 7, 2018 at 7:25 PM, Abhyankar, Shrirang G. <abhy...@anl.gov > <mailto:abhy...@anl.gov>> wrote: > The voltage magnitudes in MATPOWER data files, (bus(:,VM)), are given in per > unit and are generally close to 1.0. You have very low voltages for many of > the buses. Similarly, the VMAX and VMIN values are also in per unit and > generally they are 1.0 and 0.95, respectively. The following code results in > convergent OPF. > > > > mpc = loadcase(‘Transmission3’); > > define_constants; > > mpc.bus(:,VM) = 1.0; > > mpc.bus(:,VA) = 0.0; > > mpc.bus(:,VMAX) = 1.1; > > mpc.bus(:,VMIN) = 0.9; > > runopf(mpc); > > > > Also, note that when relaxing the limits set them to large values, not zeros. > > > > Thanks, > > Shri > > Ph: (630) 252 0219 <tel:(630)%20252-0219> > www.mcs.anl.gov/~abhyshr <http://www.mcs.anl.gov/~abhyshr> > From: <bounce-122357558-73493...@list.cornell.edu > <mailto:bounce-122357558-73493...@list.cornell.edu>> on behalf of Aakanksha > Dubey <aad...@lehigh.edu <mailto:aad...@lehigh.edu>> > Reply-To: MATPOWER discussion forum <matpowe...@list.cornell.edu > <mailto:matpowe...@list.cornell.edu>> > Date: Wednesday, March 7, 2018 at 4:23 PM > To: "MATPOWER-L@cornell.edu <mailto:MATPOWER-L@cornell.edu>" > <MATPOWER-L@cornell.edu <mailto:MATPOWER-L@cornell.edu>> > Subject: AC OPF Convergence Issue > > > > Hi All, > > > > I am developing a model for transmission grid at Lehigh Valley. My model > seems to converge for DC OPF but is unable to converge for AC. I have tried > the following to make it converge but nothing works: > > > > · Relaxed Vmax, Vmix, BR_R, Rate_A,Rate_B,Rate_C > > · Checked the tap ratio, Qmax, Qmin,Pmax,Pmin > > · Tried to change the OPF options by using opf.init_from_mpc > > · Using mpoption I tried to change the solver to IPOPT& MINOPF but > MATLAB keeps giving me an error that I need to download it. After downloading > and connecting the path to MATLAB it gives me the same error. > > I have attached my casefiles to this email. Please let me know if anyone can > find an issue with the model. > > > > Thank you! > > > > Aakanksha > > > >