Did you try the steps outlined by Jose Marin in the last entry under FAQ #5?
One other suggestion regarding the use of runcpf() is that the key is to find a modified solved power flow to start from. You could try reducing the loads to 10% of the original and running an OPF (possibly with unconstrained line) to get the base case for your CPF. Ray > On Apr 25, 2017, at 4:30 AM, Liang, Chen <[email protected]> wrote: > > Hi MatPower users: > > I'm now using MatPower to simulate the power redistribution in a cascading > failure events. However, I met some convergence issue using AC power flow to > compute the power redistribution. > > Here is what I did: > -- Use 'case2383wp' as the dataset and set branch power constraints using N-1 > security constraints. > -- Randomly select 100 line tripped as the initial line failure. > -- Extract islands and run AC power flow for each islands with at least one > generator. > -- Find new line failures and redo step 3 until there is no new failure. > > AC power flow succeed for the first round of computing the redistribution. > However, it turns not to converge for the second round for a large connected > network [see attached case_info]. On the other hand, if I change to run DC > power flow, the algorithm always gives good results. > > In addition, I tried the suggestion on FAQ 5v. Most of time runcpf doesn't > converge either. Any suggestions on how to deal with the convergence issue > for AC power flow? > > Regards, > Chen > > > > > case_info(mpc) > > Checking connectivity ... single fully connected network > Elapsed time is 0.106501 seconds. > ================================================================================ > Full > System > Number of: ---------- > buses 2060 > loads 1599 > on 1599 > off - > fixed 1599 > dispatchable - > on - > off - > generators 290 > on 290 > off - > shunt elements - > branches 2489 > on 2412 > off 77 > ties (off) - > > Load > active (MW) > dispatched 21508.1 > fixed 21508.1 > dispatchable - > nominal 21508.1 > on 21508.1 > off - > fixed 21508.1 > dispatchable - > on - > off - > reactive (MVAr) > dispatched 7176.0 > fixed 7176.0 > dispatchable - > nominal 7176.0 > on 7176.0 > off - > fixed 7176.0 > dispatchable - > on - > off - > > Generation > active (MW) > dispatched 21941.4 > max capacity 26111.4 > on 26111.4 > off - > min capacity 9146.5 > on 9146.5 > off - > reactive (MVAr) > dispatched 6286.3 > max capacity 416899.0 > on 416899.0 > off - > min capacity -403083.0 > on -403083.0 > off - > > Shunt Injections > active (MW) - > reactive (MVAr) - > > Branch Losses > active (MW) - > reactive (MVAr) - > > DC line > export (MW) > dispatch - > max capacity - > on - > off - > min capacity - > on - > off - > > Reference Buses > num of ref buses 1 > ref bus numbers 18
