Thank you for the guidance! The main issue was with the values I assumed
for Vm. My case is converging now.

sincerely,
Aakanksha *Dubey*


On Tue, Mar 13, 2018 at 9:52 AM, Ray Zimmerman <r...@cornell.edu> wrote:

> Making Vm = 1 means that the voltage is equal to its nominal value
> specified in the BASE_KV column of the bus matrix.
>
> Regarding relaxing line limits, first this is the one case where setting
> them to zero is interpreted as completely unconstrained. That is a
> reasonable thing to try in the process of trying to get a convergent case.
> The question of what sort of violations of the original limits are
> acceptable depends of course on the particular system and scenario you are
> trying to analyze/optimize.
>
>     Ray
>
>
>
> On Mar 7, 2018, at 10:21 PM, Aakanksha Dubey <aad...@lehigh.edu> wrote:
>
> Thank You, Mirish and Shri for the guidance.
>
> Shri, the model is converging now. I understand that Vmax and Vmin limits
> should have been more relaxed. I have a couple of quick follow-up
> questions:
>
>    - I had set the voltage magnitudes on per unit basis since the network
>    voltages range from 69kV to 500kV. By now making Vm=1, wouldn't all
>    voltages be set equal to 500kV?
>    - Also, while relaxing line limits, what is the maximum acceptable
>    percentage I should be increasing those values to?
>
>
> sincerely,
> Aakanksha *Dubey*
>
>
> On Wed, Mar 7, 2018 at 7:25 PM, Abhyankar, Shrirang G. <abhy...@anl.gov>
> wrote:
>
>> The voltage magnitudes in MATPOWER data files, (bus(:,VM)), are given in
>> per unit and are generally close to 1.0. You have very low voltages for
>> many of the buses. Similarly, the VMAX and VMIN values are also in per unit
>> and generally they are 1.0 and 0.95, respectively. The following code
>> results in convergent OPF.
>>
>>
>>
>> mpc = loadcase(‘Transmission3’);
>>
>> define_constants;
>>
>> mpc.bus(:,VM) = 1.0;
>>
>> mpc.bus(:,VA) = 0.0;
>>
>> mpc.bus(:,VMAX) = 1.1;
>>
>> mpc.bus(:,VMIN) = 0.9;
>>
>> runopf(mpc);
>>
>>
>>
>> Also, note that when relaxing the limits set them to large values, not
>> zeros.
>>
>>
>>
>> Thanks,
>>
>> Shri
>>
>> Ph: (630) 252 0219 <(630)%20252-0219>
>>
>> www.mcs.anl.gov/~abhyshr
>>
>> *From: *<bounce-122357558-73493...@list.cornell.edu> on behalf of
>> Aakanksha Dubey <aad...@lehigh.edu>
>> *Reply-To: *MATPOWER discussion forum <matpowe...@list.cornell.edu>
>> *Date: *Wednesday, March 7, 2018 at 4:23 PM
>> *To: *"MATPOWER-L@cornell.edu" <MATPOWER-L@cornell.edu>
>> *Subject: *AC OPF Convergence Issue
>>
>>
>>
>> Hi All,
>>
>>
>>
>> I am developing a model for transmission grid at Lehigh Valley. My model
>> seems to converge for DC OPF but is unable to converge for AC. I have tried
>> the following to make it converge but nothing works:
>>
>>
>>
>> ·         Relaxed Vmax, Vmix, BR_R, Rate_A,Rate_B,Rate_C
>>
>> ·         Checked the tap ratio, Qmax, Qmin,Pmax,Pmin
>>
>> ·         Tried to change the OPF options by using opf.init_from_mpc
>>
>> ·         Using mpoption I tried to change the solver to IPOPT& MINOPF
>> but MATLAB keeps giving me an error that I need to download it. After
>> downloading and connecting the path to MATLAB it gives me the same error.
>>
>> I have attached my casefiles to this email. Please let me know if anyone
>> can find an issue with the model.
>>
>>
>>
>> Thank you!
>>
>>
>>
>> Aakanksha
>>
>>
>>
>
>
>

Reply via email to