But the voltage solution to the OPF problem should satisfy all of the power 
flow equations. Unless I’m missing something, running …

runpf(runopf(mpc))

… should always result in immediate convergence of the power flow, without 
iterating, assuming the OPF solved successfully.

   Ray



> On Sep 9, 2016, at 3:30 AM, Jose Luis Marín <mari...@aia.es> wrote:
> 
> 
> Just a guess: OPF observes limits QMIN and QMAX on generators, while a 
> powerflow (with the standard option pf.enforce_q_lims=0) does not.  Although 
> not typical, it is certainly possible for a powerflow case to be infeasible 
> when solving without generator MVAR limits, and solvable when enforcing them.
> 
> Take a look at your OPF solution and check if there are many generators 
> pegged at their Q limits or not.
> 
> -- 
> Jose L. Marin
> Grupo AIA
> 
> 
> 
> 2016-09-08 14:45 GMT+02:00 Gamze Dogan <gamgam...@hotmail.com 
> <mailto:gamgam...@hotmail.com>>:
> Thank you for your answer,
> 
> 
> I double check and my OPF does really converge. I also checked the buses and 
> all my generators are PV and all my non-generators buses are PQ .
> I have zero island. If anyone else has an idea why I do not converge even if 
> my opf converge?
> 
> Thank you,
> 
> 
> Regards,
> 
> 
> Dogan
> 
> 
> 
> De : bounce-120759695-68616...@list.cornell.edu 
> <mailto:bounce-120759695-68616...@list.cornell.edu> 
> <bounce-120759695-68616...@list.cornell.edu 
> <mailto:bounce-120759695-68616...@list.cornell.edu>> de la part de Abhyankar, 
> Shrirang G. <abhy...@anl.gov <mailto:abhy...@anl.gov>>
> Envoyé : mercredi 7 septembre 2016 14:16
> 
> À : MATPOWER discussion forum
> Objet : Re: Problem with runcpf
>  
> Are you sure the OPF converged? If it did, then I guess you are not setting 
> the bus types correctly or there is still some error in your system data. 
> Note that the first step of a continuation power flow is running a load flow. 
> So if the load flow does not converge then continuation power flow will not 
> either.
> 
> On Sep 5, 2016, at 9:52 AM, Gamze Dogan <gamgam...@hotmail.com 
> <mailto:gamgam...@hotmail.com>> wrote:
> 
>> Thank you for your answer,
>> 
>> 
>> I actually had an island, but the problem remains. Now I am sure that there 
>> are no island.
>> 
>> The load flow does not converge. 
>> I tried to launch a fast decoupled, but it does not converge. 
>> The OPF converged and I used the results of Vm and Va as the initial guess 
>> to relauch my load flow, but it still does not converge.
> 
> 
>> 
>> I tried to check the system load using runcpf, but it does not converge, 
>> here is the message:
>> 
>> MATPOWER Version 5.1, 20-Mar-2015 -- AC Continuation Power Flow
>> step   1 : lambda = 26502.011, corrector did not converge in 10 iterations
>> 
>> >>>>>  Did NOT converge (0.20 seconds)  <<<<<
>> 
>> 
>> Do you have any suggestion on how I can make it converge?
>> 
>> Thank you,
>> 
>> Dogan
>> 
>> 
>> 
>> De : bounce-120746902-68616...@list.cornell.edu 
>> <mailto:bounce-120746902-68616...@list.cornell.edu> 
>> <bounce-120746902-68616...@list.cornell.edu 
>> <mailto:bounce-120746902-68616...@list.cornell.edu>> de la part de 
>> Abhyankar, Shrirang G. <abhy...@anl.gov <mailto:abhy...@anl.gov>>
>> Envoyé : vendredi 2 septembre 2016 13:42
>> À : MATPOWER discussion forum
>> Objet : Re: Problem with runcpf
>>  
>> I suspect you have isolated buses or islands that do not have a swing bus. 
>> Have you tried I-iv in MatPower faq on power flow divergence.
>> 
>> http://www.pserc.cornell.edu/matpower/#pfconvergence 
>> <http://www.pserc.cornell.edu/matpower/#pfconvergence>
>> 
>> Shri
>> 
>> On Sep 2, 2016, at 6:51 AM, Gamze Dogan <gamgam...@hotmail.com 
>> <mailto:gamgam...@hotmail.com>> wrote:
>> 
>>> Dear all,
>>> 
>>> I have a problem when using runpf which does not converge. Therefore, I 
>>> tried to check if the system load exceeded the steady-state loading limit 
>>> (as mentionned on the website)
>>> 
>>> define_constants;
>>>     mpcbase = loadcase('casefile');
>>>     mpcbase.bus(:, PD) = 0;
>>>     mpcbase.bus(:, QD) = 0;
>>>     mpcbase.gen(:, PG) = 0;
>>>     mpctarget = loadcase('casefile');
>>>     results = runcpf(mpcbase, mpctarget);
>>>     results.cpf.max_lam
>>> 
>>> But I have a problem using the function runcpf, it gives me the following 
>>> error message:
>>> Warning: Matrix is singular to working precision. 
>>> > In cpf_corrector at 124
>>>   In runcpf at 257
>>> step   1 : lambda =    NaN, corrector did not converge in 10 iterations
>>> ??? NaN's cannot be converted to logicals.
>>> 
>>> Error in ==> printpf at 175
>>>     nzld = find((bus(:, PD) | bus(:, QD)) & bus(:, BUS_TYPE) ~= NONE);
>>> 
>>> Error in ==> runcpf at 392
>>> printpf(results, 1, mpopt);
>>> 
>>> I do not understand what the problem is. Any suggestion is wellcome. 
>>> 
>>> Thank you,
>>> 
>>> G. Dogan
>>> 
>>> 
>>> 
> 

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