OPF convergence issue with piecewise linear cost
Dear all, I wanted to compare the results of the OPF with the two types of model for the generator costs (polynomial and piecewise linear cost). So first, I launched an OPF with polynomial cost which converged, then I launched one with linear cost and it does not converge. I know that my formulation of the linear cost is correct as it has already converged for several cases, but for some it does not. As the first OPF has converged, it means that there is an electrical solution to my problem, but with linear cost it seem that the OPF cannot verify the constraints on the cost function (minimal f(x)). I suppose that there is a way to make it converge, do you have any idea how? Thank you for your time, Gamze
OPC with piecewise linear cost: non convergent
Dear all, I wanted to compare the results of the OPF with the two types of model for the generator costs (polynomial and piecewise linear cost). So first, I launched an OPF with polynomial cost which converged, then I launched one with linear cost and it does not converge. I know that my formulation of the linear cost is correct as it has already converged for several cases, but for some it does not. As the first OPF has converged, it means that there is an electrical solution to my problem, but with linear cost it seem that the OPF cannot verify the constraints on the cost function (minimal f(x)). I suppose that there is a way to make it converge, do you have any idea how? Thank you for your time, D.G.
FW: Opf convergence problem
Dear all, To complete my previous e-mail (see below) , I also get the following message: Warning: Element(s) of class 'opf_model' do not match the current constructordefinition. The element(s) have been converted to structures If anybody can help me resolve the problem I would really appreciate it, Thank you, Gamze From: gamgam...@hotmail.com To: matpowe...@list.cornell.edu Subject: Opf convergence problem Date: Mon, 14 Sep 2015 11:14:15 + Dear all, I have a convergence problem when running the OPF. When I used the Matpower vesion 4.1 my casefile converged in pf but not in opf. I have recently installed the new version of Matpower 5.1 and when running the opf I get the following message which I do not understand: ??? Error using ==> classCannot change the number of fields of class 'opf_model' without first typing 'clearclasses'.Error in ==> opf_model.opf_model at 66om = class(s, 'opf_model', om);Error in ==> opf_setup at 202om = opf_model(mpc);Error in ==> opf at 200om = opf_setup(mpc, mpopt);Error in ==> uopf at 117[results, success] = opf(mpc, mpopt);Error in ==> runuopf at 78[r, success] = uopf(casedata, mpopt); Could someone explain to me what the problem is? Thank you for any suggestion. You can find attached the case file (mpz) the results of the pf (resultsLF) and the results of the opf (resultsOPF) when using Matpower 4.1 Any suggestion on how not to get that error message and/or how to reach convergence is welcome, Thank you, Gamze case5998.mat Description: Binary data
Opf convergence problem
Dear all, I have a convergence problem when running the OPF. When I used the Matpower vesion 4.1 my casefile converged in pf but not in opf. I have recently installed the new version of Matpower 5.1 and when running the opf I get the following message which I do not understand: ??? Error using ==> classCannot change the number of fields of class 'opf_model' without first typing 'clearclasses'.Error in ==> opf_model.opf_model at 66om = class(s, 'opf_model', om);Error in ==> opf_setup at 202om = opf_model(mpc);Error in ==> opf at 200om = opf_setup(mpc, mpopt);Error in ==> uopf at 117[results, success] = opf(mpc, mpopt);Error in ==> runuopf at 78[r, success] = uopf(casedata, mpopt); Could someone explain to me what the problem is? Thank you for any suggestion. You can find attached the case file (mpz) the results of the pf (resultsLF) and the results of the opf (resultsOPF) when using Matpower 4.1 Any suggestion on how not to get that error message and/or how to reach convergence is welcome, Thank you, Gamze case5998.mat Description: Binary data
OPF question convergence
Dear all,
I have a very strange problem using the matpower function runuopf.
I launch several iteration of runuopf and one case give me a non convergent
solution (success flag is zero).
Within my code, I save the values the runuopf function uses, so it goes:
save casefileresultsOPF = runuopf(casefile,mpoption('OUT_ALL', 0, 'VERBOSE', 0,
'OPF_FLOW_LIM', 2));
So then, after the simulation ends, I wanted to see why the OPF did not
converge, but, when I opened matlab and loaded the casefile, this one
succeeded So I just did:
load casefile;resultsOPF3 = runuopf(casefile,mpoption('OUT_ALL', 0, 'VERBOSE',
0, 'OPF_FLOW_LIM', 2));
But this one succeeds which is not consistent with the results I got from the
function within the whole simulation.
Did anyone ever had that kind of problem?
Here, you can fin attached, the casefile (datacase), the results within the
simulation, which does not converge (resultsSIM) and the results after the
simulation, using the casefile, and which does converge (results)
Any suggestion on how to explain and/or avoid this, is wellcome, thank you very
much,
G.D.
datacase.mat
Description: Binary data
resultsSIM.mat
Description: Binary data
results.mat
Description: Binary data
RE: Branch flow limits in OPF
Thank you for your answer. Is there a way to limit both current and apparent power? Thank you, Gamze From: r...@cornell.edu Subject: Re: Branch flow limits in OPF Date: Wed, 25 Mar 2015 11:03:03 -0400 To: matpowe...@list.cornell.edu By default, the “flow” constraint in the AC OPF is on apparent power (in the DC OPF, it’s active power), not on current, which probably explains what you are seeing. See the 'opf.flow_lim' option to change the default. Ray On Mar 25, 2015, at 4:55 AM, Gamze Dogan gamgam...@hotmail.commailto:gamgam...@hotmail.com wrote: Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
Branch flow limits in OPF
Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
Problem using dispatchable loads
Hi, I want to use dispatchable load in my work, but I have issues whenever I try to use it. The results of the OPF gives me positive values of Pg for my dispatchable loads. It seems very strange to me as I put the correct values for Pmax and Pmin for the fictious generators and when I check using isload it clearly gets that I have dispatchable load but the OPF does not get me negative values for Pg, thus all my dispatchable loads are outside their [Pmin, Pmax] boundary. None of my cases with dispatchable loads work, do you have an idea why? The error message is the following: MATPOWER Version 4.1, 14-Dec-2011 -- AC Optimal Power Flow MATLAB Interior Point Solver -- MIPS, Version 1.0, 07-Feb-2011 itobjective step size feascond gradcond compcond costcond - 0 34354.266 0.000145177 2.74983 8817.60 1-26584.096 2.6085 8.10986e-005 3.28039 71.5144 1.3739 2-16333.508 2.2816 3.32505e-005 1.06999 21.5867 0.280192 3-4648.9026 3.069 2.14625e-005 0.766689 10.2045 0.443716 4 978.66593 2.5377 1.72341e-005 0.606444 6.07282 0.384163 5 7029.0382 0.8612 1.44116e-005 0.511965 4.89929 0.551103 6 39261.0340.94397 1.24046e-005 0.754135 3.49051 1.89277 7 373268.42 1.0068 6.55614e-006 0.381628 1.78104 6.78036 8 393954.160.60311 6.34104e-006 0.122038 1.508980.0539719 9 394299.03 1.0444 6.33887e-0060.0357471 1.49993 0.000853718 10 775476.9 1.0468 4.4557e-0060.0300993 1.0427 0.942812 11 923044.66 1.0104 3.86301e-0060.0278763 0.80815 0.18787 12 1161795.90.89595 3.09519e-0060.0171514 0.64877 0.255884 13 1161809.20.99041 3.09515e-006 0.000738529 0.634124 1.13676e-005 14 1161815.70.75462 3.09508e-006 8.11485e-008 1.66624 5.54037e-006 15 1161815.70.78779 3.09508e-006 3.27326e-010 27.8727 4.83558e-008 16 1161815.70.98894 3.09508e-006 2.94949e-011 1.36126e+008 2.48268e-012 Numerically Failed Did not converge in 16 itérations. Thank you for help; I realize my question is very large as it might not work for a lot of reasons related to the cases but my concern is that my dispatchable loads have positive values for Pg which does not make any sense to me. Regards, Gamze
OPF with current constraints
Hi, I have a question about using current constraints in my OPF. I did it using the OPF FLOW LIMIT assigned to 2. First, I want to be sure to understand how the constraints work, if the OPF does not find a solution that meets the requirements, it will not converge, is this right? Then, I have a second question, how can I define a constraint on the current and put a cost on it? Actually what I want to try to do is the following: 1. I want my opf to find a solution respecting the current constraints, and if it does, the cost related to it will be zero 2. If my opf does not find a solution that respects the current constraints, I still want that it gives me an answer, but I want it to have a very high cost Is it possible to do that? SHould I implemented the current constraints using the user-defined constraints? Thank you for your help, Gamze Dogan
RE: OPF with current limit
Thank you very much for your help! I have another question. I want my opf to stop as soon as it finds an answer respecting the constraints (I have a constraint on the current in the branches). Thus, I don't want it to find the optimal solution but just the first one. Is it possible to do that? Thank you for your help, Gamze From: abhy...@mcs.anl.gov To: matpowe...@list.cornell.edu Subject: Re: OPF with current limit Date: Wed, 16 Jul 2014 10:54:55 + On Jul 16, 2014, at 2:04 AM, Gamze Dogan gamgam...@hotmail.com wrote: Hi, I want to implement the OPF with current limit of the branches, I did using the option 'OPF_FLOW_LIM',2 This will apply current limits on all branches except those whose flows have been specified as infinite. If I understand well, this will limit my current in all branches (exept one involving the slack bus) to 1 pu? Is this right? How can I modify it to have a limit at 1.2 pu? Set the branch RATE_A limit. Then I wanted to know if this was the right way to calculate my current: Sf(d,1) = (results.branch(d, 14)/results.baseMVA) + 1j * (results.branch(d, 15)/results.baseMVA); Vf(d,1) = results.bus(results.branch(d,1), 8) * exp(1j * results.bus(results.branch(d,1), 9)*pi/180); If(d,1) = conj( Sf(d,1) / Vf(d,1) ); [Ybus, Yf, Yt] = makeYbus(mpc); % mpc is your case file struct. If = Yf*V; % from bus currents It = Yt*V; % to bus currents Thank you for your help; Gamze
OPF with current limit
Hi, I want to implement the OPF with current limit of the branches, I did using the option 'OPF_FLOW_LIM',2 If I understand well, this will limit my current in all branches (exept one involving the slack bus) to 1 pu? Is this right? How can I modify it to have a limit at 1.2 pu? Then I wanted to know if this was the right way to calculate my current: Sf(d,1) = (results.branch(d, 14)/results.baseMVA) + 1j * (results.branch(d, 15)/results.baseMVA); Vf(d,1) = results.bus(results.branch(d,1), 8) * exp(1j * results.bus(results.branch(d,1), 9)*pi/180); If(d,1) = conj( Sf(d,1) / Vf(d,1) ); Thank you for your help; Gamze
Question: out-of-service status
Hi, I have a question about the status of lines and generators. I want one of my generators to be out-of-service in all cases, but my opf sometimes puts it in service (for emergency cases I suppose). How can I make sure that the generator will not be used? (I'm changing the out-of-service generator in each loop so I do not want to erase it from my case) Thank you for your help, Gamze Dogan
