Dear Mr.Shree, Thank you very much for your help. As per your suggestion and FAQ I tried to find out the problems. The results I got- 1) Fast-decoupled power flow did not converge in 30 iterations. 2) By following http://www.pserc.cornell.edu/matpower/#pfconvergence I tried to runcpf to get good initial guess and i got results like step 1 : lambda = 0.084, corrector did not converge in 10 iterations. Where lambda is < 1 and for reducing steady state loading limitation I reduced demand less than 60 % which also failed to converge the power flow. 3) Also I tried to run an optimal power flow according to Dr. Ray's explanation given in following link-
*https://www.mail-archive.com/search?l=matpower-l@cornell.edu&q=subject:%22Re%5C%3A+%5C%5BMatpower%5C%5D+3500+bus+simulation%22&o=newest <https://www.mail-archive.com/search?l=matpower-l@cornell.edu&q=subject:%22Re%5C%3A+%5C%5BMatpower%5C%5D+3500+bus+simulation%22&o=newest>* but got the results like- MATPOWER Version 5.1, 20-Mar-2015 -- AC Optimal Power Flow MATLAB Interior Point Solver -- MIPS, Version 1.2, 20-Mar-2015 (using built-in linear solver) it objective step size feascond gradcond compcond costcond ---- ------------ --------- ------------ ------------ ------------ ------------ 0 1200199.7 2.41677 0.71 536.762 0 1 946197.39 15.531 1.3682 1.75871 525.914 0.209885 2 954529.91 15.405 0.766107 0.203773 297.341 0.00871422 3 954849.8 12.849 0.727712 0.0545952 258.471 0.00033166 4 954629.03 13035 0.69114 0.107402 258.048 0.000228815 5 954614.88 33406 0.692682 0.255673 257.828 1.46744e-05 6 954525.69 14111 0.579613 0.143897 256.765 9.24569e-05 7 954539.42 61648 0.581139 0.501345 255.994 1.42362e-05 8 954518.93 22452 0.573652 0.478609 255.465 2.12443e-05 9 954494.92 8540.4 0.556318 0.403754 254.653 2.48944e-05 10 954523.58 20366 0.556265 0.570707 254.104 2.97206e-05 11 954522.07 6142.4 0.554989 0.647881 256.561 1.57288e-06 12 954573.42 6192.9 0.513972 0.716706 253.604 5.32434e-05 13 954575.97 5912.1 0.509457 0.699751 252.612 2.64406e-06 14 954576.23 16534 0.509454 0.674865 253.278 2.64555e-07 15 954579.65 12324 0.509394 0.812237 252.966 3.54362e-06 16 954579.86 7650.3 0.509391 0.80973 252.948 2.18359e-07 17 954579.87 8185.1 0.509391 0.809591 252.947 1.48635e-08 18 954579.88 8696.2 0.509391 0.809411 252.945 1.31087e-08 19 954579.9 9392.5 0.50939 0.80927 252.943 1.3818e-08 Numerically Failed Did not converge in 19 iterations. >>>>> Did NOT converge (3.71 seconds) <<<<< 4) But when I used spy(J) , to look jacobian matrix it gives me some strange distribution. Herewith I attached image of jacobian matrix. ( I have modeled transmission lines and transformers to get one single branch matrix e.g. branch_matrix=vertcat(transmission_lines,grid_transformer) which is similar to matpower test cases.). So could you please suggest me what necessary steps I should follow? Thank you for your time. Regards Mirish Thakur KIT, University. On Mon, Aug 10, 2015 at 7:14 PM, Abhyankar, Shrirang G. <abhy...@anl.gov> wrote: > I would suggest trying the following: > > > 1. Use the solution of a fast decoupled power flow or an optimal power > flow (with line limits and voltage limits relaxed) as the initial guess for > the power flow. > 2. Follow step 5 in > http://www.pserc.cornell.edu/matpower/#pfconvergence making CPF to > stop when the nose-point is reached. This can be done via results = > runcpf(mpcbase,mpctarget,mpoption(‘cpf.stop_at’,’NOSE’)). If > results.cpf.max_lam is >= 1, then it shows that the initial guess for the > power flow is the problem for its divergence. To obtain a ‘good’ initial > guess, run the continuation power flow again making it to stop exactly at > lam = 1 (the target case loading and generation) via results = > runcpf(mpcbase,mpctarget,mpoption(‘cpf.stop_at’,1.0)). You can then save > the results struct as a matpower case file (via savecase()). On the other > hand, if results.cpf.max_lam < 1, then the loading/generation in your > original case is beyond the system steady-state loading limit. > > Shri > From: Mirish Thakur <mirishtha...@gmail.com> > Reply-To: MATPOWER discussion forum <matpowe...@list.cornell.edu> > Date: Monday, August 10, 2015 at 10:44 AM > To: MATPOWER discussion forum <matpowe...@list.cornell.edu> > Subject: convergence problem in runpf. > > Dear Matpower Community, > > > I’m working on power flow project and have used grid data from database. I > have modelled all line parameters (R X B) in p.u. system, also same for > transformers and kept generator output until it satisfies active and > reactive power demand. For renewable generation, I specified as negative > demand on respective buses. I checked all possibilities mentioned in FAQ ( > http://www.pserc.cornell.edu/matpower/#pfconvergence ) but couldn’t > figure out problem. Also I checked (case_info) to see any island but got > full system without island. To make the problem simple I used all buses as > PQ buses except one slack bus. Also my casefile converges for rundcpf but > fails to runpf and gives error like ‘Newton's method power flow did not > converge in 10 iterations.’ Also I found that when I use following code- > > > opt = mpoption('OUT_BUS', 0, 'OUT_BRANCH', 0, 'VERBOSE', 2); > > mpc = loadcase('casefile'); > > results =runpf(mpc,opt); > > > may be it gives me divergence of PQ mismatch instead of convergence. > > > MATPOWER Version 5.1, 20-Mar-2015 -- AC Power Flow (Newton) > > > > it max P & Q mismatch (p.u.) > > ---- --------------------------- > > 0 2.296e+01 > > 1 1.729e+01 > > 2 2.450e+03 > > 3 2.352e+03 > > 4 6.962e+06 > > 5 1.740e+06 > > 6 4.352e+05 > > 7 1.753e+07 > > 8 4.382e+06 > > 9 3.322e+06 > > 10 8.303e+05 > > Newton's method power flow did not converge in 10 iterations. > > > > >>>>> Did NOT converge (0.23 seconds) <<<<< > > > > > > results = > > version: '2' > > baseMVA: 100 > > bus: [1086x13 double] > > gen: [467x21 double] > > branch: [2145x17 double] > > order: [1x1 struct] > > et: 0.2320 > > success: 0 > > I will be very thankful for your help. > > > Regards > > Mirish Thakur. > > KIT, University. > >
jacobian_matrix.fig
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