From: <bounce-122358024-73493...@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 9:21 PM
To: MATPOWER discussion forum <matpowe...@list.cornell.edu>
Subject: Re: AC OPF Convergence Issue
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?
I suggest referring to a book on per unit calculation. Here’s a simple example
that may help get your started:
http://peguru.com/2011/06/per-unit-system-practice-problem-solved-for-easy-understanding/
· Also, while relaxing line limits, what is the maximum acceptable
percentage I should be increasing those values to?
There is no acceptable or unacceptable percentage. The line limits are relaxed
simply to get the OPF to converge, but this may not be realistic for a
practical solution.
Shri
sincerely,
Aakanksha Dubey
On Wed, Mar 7, 2018 at 7:25 PM, Abhyankar, Shrirang G.
<abhy...@anl.gov<mailto: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<tel:(630)%20252-0219>
www.mcs.anl.gov/~abhyshr<http://www.mcs.anl.gov/~abhyshr>
From:
<bounce-122357558-73493...@list.cornell.edu<mailto:bounce-122357558-73493...@list.cornell.edu>>
on behalf of Aakanksha Dubey <aad...@lehigh.edu<mailto:aad...@lehigh.edu>>
Reply-To: MATPOWER discussion forum
<matpowe...@list.cornell.edu<mailto:matpowe...@list.cornell.edu>>
Date: Wednesday, March 7, 2018 at 4:23 PM
To: "MATPOWER-L@cornell.edu<mailto:MATPOWER-L@cornell.edu>"
<MATPOWER-L@cornell.edu<mailto: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
