Thank you, Ray. From: [email protected] Subject: Re: Branch minimisation loss error message Date: Tue, 18 Sep 2012 10:06:56 -0400 To: [email protected]
I have no way of knowing what your user defined program does, but it *appears* that it somehow eliminates the reference bus before calling opf(). You may try putting a breakpoint at line 126 in mipsopf_solver() to confirm that there is no reference bus at that point in the code. dbstop 126 mipsopf_solver -- Ray ZimmermanSenior Research Associate419A Warren Hall, Cornell University, Ithaca, NY 14853phone: (607) 255-9645 On Sep 17, 2012, at 5:32 PM, Richard Ngonga wrote:Thanks Ray, but I do have a reference bus and my case file is giving me the right results when I run a pf or opf. My network has 80 buses and two generators, on of which is a refernce bus. From: [email protected] Subject: Re: Branch minimisation loss error message Date: Mon, 17 Sep 2012 09:17:07 -0400 To: [email protected] It means that you do not have a reference bus defined in your case file. One of the buses should have the BUS_TYPE column (2) set to REF (3). -- Ray ZimmermanSenior Research Associate419A Warren Hall, Cornell University, Ithaca, NY 14853phone: (607) 255-9645 On Sep 14, 2012, at 1:41 AM, Richard Ngonga wrote:I am getting the following error message whenever I try running a user defined program to minimize branch losses(min_power_exchange) using my case file. This problem doesn't occur when I try running the program with a Matpower supplied case file. Can you please tell me what the error message means? ??? Attempted to access Varefs(1); index out of bounds because numel(Varefs)=0. Error in ==> mipsopf_solver at 127 x0(vv.i1.Va:vv.iN.Va) = Varefs(1); %% angles set to first reference angle Error in ==> opf_execute at 106 [results, success, raw] = feval(solver, om, mpopt); Error in ==> opf at 225 [results, success, raw] = opf_execute(om, mpopt); Error in ==> runopf at 96 [r, success] = opf(casedata, mpopt); Error in ==> min_power_exchange at 237 [results, success] = runopf(mpc, mpopt); Error in ==> testng at 15 results = min_power_exchange(mpc,mpopt); Bellow is my program code mpc = loadcase('case803.m'); mpopt = mpoption( 'VERBOSE',0,'OUT_ALL',0); mpc = runopf(case803,mpopt); define_constants; % %% create map of external bus numbers to bus indices i2e = mpc.bus(:, BUS_I); e2i = sparse(max(i2e), 1); e2i(i2e) = (1:size(mpc.bus, 1))'; % %% ties lines ties = find(mpc.bus(e2i(mpc.branch(:, F_BUS)), BUS_AREA) ~= mpc.bus(e2i(mpc.branch(:, T_BUS)), BUS_AREA)); ties_idx = [mpc.branch(ties, F_BUS) mpc.branch(ties, T_BUS)]; flow_t0 = [mpc.branch(ties, PF) mpc.branch(ties, QF)]; % % Reduction of the load at bus 26 %mpc.bus(26,[PD QD]) = 0.8*mpc.bus(26,[PD QD]); results = min_power_exchange(mpc,mpopt); flow_tf = [results.branch(ties, PF) results.branch(ties, QF)]; % % difference of the tie flows flow_t0 - flow_tf
