Hi Shruti,
It appears that this is a bug, could you please submit it to the issue tracker
on GitHub <https://github.com/MATPOWER/matpower/issues>.
I haven’t finished tracking it down, but it looks like it’s related to the fact
that the bus gets converted to a PQ bus during the initial power flow, before
the continuation even starts. Then, for some reason, the solved reactive power
setting (which is equal to Qmax at 35 MVAr) is not carried over to the target
case. So, when the continuation begins, the target case has Qg = 0, the base
case has Qg = 35 and in both cases it is a PQ bus.
Thanks for reporting this,
Ray
> On Dec 30, 2016, at 11:06 PM, Shruti Rao <[email protected]> wrote:
>
> Hi everyone,
>
>
> I had a question about the CPF function in MATPOWER6.0 which I am using to to
> check the limit induced bifurcation (LIB) points of different systems.
>
> I noticed for case300, while the maximum generator var limits were being
> respected, the minimum var limit of one generator was being violated at the
> LIB. The generator at bus number 76 (generator status is 1), has a QG of 0
> MVAr at the LIB whereas its minimum QG is 12 MVAr. Hence, the violation was
> greater than the default tolerance for limit detection (0.01 MVAr).
>
> Also, for an ERCOT test case, 33 generators were violating the max. var
> limit, while 61 generators were violating the min. var limit out of 531
> committed generators.
>
>
> Here is a sample code I used:
> mpcb=loadcase('case300');
> mpct = mpcb; % set up target case with
> mpct.bus(:, PD) = mpcb.bus(:, PD)*5; % and increased load
> mpct.bus(:, QD) = mpcb.bus(:, QD)*5; % and increased load
> mpct.gen(:, PG) = mpcb.gen(:, PG)*5; % and increased gen
> mpopt = mpoption('cpf.stop_at',
> 'NOSE','cpf.enforce_q_lims',1,'cpf.enforce_p_lims',0);
> results = runcpf(mpcb, mpct, mpopt);
>
>
> Am I doing something incorrectly or is there any additional options that I
> should be setting?
>
> Thank you and a happy new year to you!
>
> Regards,
> Shruti Dwarkanath Rao
>
> Graduate Research Associate, Arizona State University
> Tempe, AZ, 85281
> 650 996 0116
