You would have to confirm the cause of the non-convergence before drawing any conclusions. You may find FAQ #5<https://matpower.org/doc/faq/#pfconvergence> helpful.
Ray On Sep 12, 2020, at 6:43 AM, Surbhi Aggarwal <surbhiaggarwa...@gmail.com<mailto:surbhiaggarwa...@gmail.com>> wrote: Hello If the system does not converge within 10 iterations, can we say that it is one of the most severely affected lines in contingency studies? Or any other explanation for this non-convergence? Regards Surbhi Aggarwal On Sat, Sep 12, 2020 at 10:40 AM Surbhi Aggarwal <surbhiaggarwa...@gmail.com<mailto:surbhiaggarwa...@gmail.com>> wrote: Hello Thank you all for your help and I'll definitely look out for the solutions. Thank you so much Regards Surbhi Aggarwal On Fri, Sep 11, 2020 at 7:16 PM Ray Daniel Zimmerman <r...@cornell.edu<mailto:r...@cornell.edu>> wrote: Hi Surbhi, It looks like you were using the default Newton power flow. To increase the number of iterations, you can increase the pf.nr.max_it option. However, this is rarely necessary. If the Newton method is going to converge, it usually does so in less than the default 10 iterations. If it is not converging within 10 iterations, it is likely that the problem has no solution or that you need a better starting point. Ray On Sep 11, 2020, at 5:48 AM, Mirish Thakur <mirishtha...@gmail.com<mailto:mirishtha...@gmail.com>> wrote: Hi Surbhi, First of all why do you want to increase the number of steps/ iterations in the calculation? Is there any specific need? Actually the number of iterations depends on the power flow optimization tolerance. Maybe you can focus on the mpoption function and read it carefully. You can update something like here: mpopt = mpoption('pf.alg', 'FDXB', 'pf.tol', 1e-4) I'm not 100 % sure about it but it may help you. Thanks. Kind regards Mirish On Fri, Sep 11, 2020 at 8:41 AM Surbhi Aggarwal <surbhiaggarwa...@gmail.com<mailto:surbhiaggarwa...@gmail.com>> wrote: Hello Everyone, I tried your suggestions and it somehow helped me. Now my doubt is " If I want to increase my number of iterations, what steps I have to do"? Please help me out Regards Surbhi Aggarwal On Wed, Sep 9, 2020 at 7:50 PM Ray Daniel Zimmerman <r...@cornell.edu<mailto:r...@cornell.edu>> wrote: I also suspect that the network becomes disconnected by removing certain lines. You can check the connectivity using case_info()<https://matpower.org/docs/ref/matpower7.0/lib/case_info.html> or find_islands()<https://matpower.org/docs/ref/matpower7.0/lib/find_islands.html>. If there are islands, then each island needs to have its own reference bus, and the local generation needs to be able to meet the local load in each island. Ray On Sep 9, 2020, at 4:57 AM, Mirish Thakur <mirishtha...@gmail.com<mailto:mirishtha...@gmail.com>> wrote: Hi Surbhi, Could you please check the continuity of the system before running opf? I mean to say if you run opf for (n-1) criteria the system should be still well connected. There shouldn't be any island within the system itself. Perhaps you can test your model by removing any one parallel line (which you can observe later for analysis) and run the model under (n-1) criteria. This could be the easiest way to test the model. Thank you. Kind regards Mirish On Wed, Sep 9, 2020 at 9:11 AM Surbhi Aggarwal <surbhiaggarwa...@gmail.com<mailto:surbhiaggarwa...@gmail.com>> wrote: Dear All, I am working on optimal power flow to find the contingency (N-1) situation of the system. For some of the line outage, certain output pops out MATPOWER Version 7.0, 20-Jun-2019 -- AC Power Flow (Newton) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Warning: Matrix is singular to working precision. > In mplinsolve (line 75) In newtonpf (line 110) In runpf (line 260) Newton's method power flow (power balance, polar) did not converge in 10 iterations. >>>>> Did NOT converge (7.38 seconds) <<<<< What to do to correct this error. It would be of great help. Regards Surbhi Aggarwal
