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<mailto:mirishtha...@gmail.com>> Reply-To: MATPOWER discussion forum <matpowe...@list.cornell.edu<mailto:matpowe...@list.cornell.edu>> Date: Monday, August 10, 2015 at 10:44 AM To: MATPOWER discussion forum <matpowe...@list.cornell.edu<mailto: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.
