Sorry, that output should have included the following …
MATPOWER Version 5.0, 17-Dec-2014 -- AC Power Flow (Newton)
it max P & Q mismatch (p.u.)
---- ---------------------------
0 5.074e-11
Converged!
Guess I copied it from a run with ‘verbose’ = 0.
Ray
> On Jan 29, 2015, at 9:37 AM, Ray Zimmerman <r...@cornell.edu> wrote:
>
> Hi Dominic,
>
> I don’t think there is any bug here. First of all, the issue of the power
> flow converging in 1 iteration as opposed to zero is simply an issue of the
> termination tolerances. The issue of non-matching reactive power outputs is
> related to the fact that there are two generators at the same bus, either of
> which could generate the reactive power. The total reactive power injected at
> the bus is the same in both solutions, so the power flow equations are
> satisfied in both cases. The OPF solution has all of the reactive supply at
> the bus coming from one of the two generators. The power flow code splits the
> reactive injection between multiple units proportional to the reactive range
> of each unit.
>
> The following code (also in attached script file) results in the output below
> and will hopefully qualm any doubts ...
>
> define_constants;
> load mpc123b
> mpopt = mpoption('opf.ac.solver', 'MIPS', 'mips.comptol', 1e-10,
> 'mips.step_control', 1);
> mpopt = mpoption(mpopt, 'out.all', 0);
> r1 = runopf(mpc123, mpopt);
> mpopt = mpoption(mpopt, 'verbose', 2);
> r2 = runpf(r1, mpopt);
> compare_case(r1, r2)
> k = find(r1.gen(:, GEN_BUS) == r1.gen(220, GEN_BUS))
> [r1.gen(k, QG) r2.gen(k, QG)]
> sum([r1.gen(k, QG) r2.gen(k, QG)])
>
>
> >> test123
>
> MATPOWER Version 5.0, 17-Dec-2014 -- AC Optimal Power Flow
> MATLAB Interior Point Solver -- MIPS-sc, Version 1.1, 17-Dec-2014
> Converged!
>
> MATPOWER Version 5.0, 17-Dec-2014 -- AC Power Flow (Newton)
> ---------------- -------------- -------------- -------------- -----
> matrix / col case 1 case 2 difference row
> ---------------- -------------- -------------- -------------- -----
> bus
> VM 1.1 1.1 2.22045e-16 44
> VA 35.2787 35.2787 1.42109e-14 180 *
>
> gen
> PG 6.4271e-10 6.38956e-10 3.75491e-12 3414
> QG 1.02725e-10 494.118 494.118 220 *
>
> branch
> PF 75.2832 75.2832 2.81496e-09 2148 *
> QF 8.577 8.577 1.48452e-09 2148
> PT -75.2831 -75.2831 2.81496e-09 2148
> QT -8.65882 -8.65882 1.48449e-09 2148
>
> k =
>
> 219
> 220
>
>
> ans =
>
> 867.6421 373.5236
> 0.0000 494.1184
>
>
> ans =
>
> 867.6421 867.6421
>
>
> --
> Ray Zimmerman
> Senior Research Associate
> B30 Warren Hall, Cornell University, Ithaca, NY 14853 USA
> phone: (607) 255-9645
>
> <test123.m>
>
>> On Jan 28, 2015, at 1:42 PM, Hewes, Dominic <dominic.he...@tum.de
>> <mailto:dominic.he...@tum.de>> wrote:
>>
>> Dear Matpower Community,
>>
>> I am observing a strange problem whereby the results from a successful
>> 'runopf()' do not seem to present a solved power flow case. I want to verify
>> the power flow solution from an OPF by running a PF with the OPF results as
>> the mpc struct. Firstly, the 'runpf()' converges in 1 iteration, whereas i
>> would expect a solved case to converge in 0 iterations- am i mistaken here?
>> Secondly, when i use the 'compare_case()' command to compare the OPF results
>> with the resulting PF results, I see that there are large differences
>> between the solutions. My code is as follows:
>>
>> resultsOPF=runopf(mpc123);
>> resultsPF=runpf(resultsOPF);
>>
>> compare_case(resultsOPF, resultsPF)
>>
>> The comparison shows a maximum reactive power difference of 494 MVAR between
>> the generator results:
>>
>> gen
>> PG 5.00578e-10 9.67145e-09 9.17088e-09 614
>> QG 7.99959e-11 494.118 494.118 218 *
>>
>> The OPF command converges successfully with no error warnings, and so I
>> assumed that running the results struct through a PF command should give the
>> same power flow solution. Am i mistaken here? If my thinking is correct,
>> this would indicate that the optimiser has provided results that do not
>> represent a feasible power flow solution - is this potentially a bug? I have
>> tested the same method on the 'case14.m' file and observe that this also
>> requires 1 iteration to converge and gives very small differences (~2e-7)
>> between the OPF and PF results.
>>
>> I am using the latest matpower release (5.0), the TSPOPF 5.0 solver and a
>> windows 7 machine (see output of mpver at end of email). I have tried with
>> other solvers and observe the same problem. I am working with a large model
>> (>5000 bus) that i have attached below. Could the size of my model be the
>> cause of this problem?
>>
>> Presently I am not sure whether I am making a simple mistake or if there is
>> a bug in the solver that is causing the output of inaccurate results.
>>
>> Has anyone experienced similar problems? I would very much appreciate any
>> advice on the cause of the problem.
>>
>> Kind Regards,
>>
>> Dominic
>>
>>
>> mpver
>>
>> MATPOWER Version 5.0 17-Dec-2014
>> MATLAB Version 8.4 08-Sep-2014 Release: (R2014b)
>> Optimization Toolbox Version 7.1 08-Sep-2014 Release: (R2014b)
>> MIPS Version 1.1 17-Dec-2014
>> SDP_PF -- not installed --
>> YALMIP -- not installed --
>> BPMPD_MEX -- not installed --
>> CPLEX Version 12.6.0.0 PCWIN64
>> Gurobi -- not installed --
>> GLPK -- not installed --
>> IPOPT -- not installed --
>> KNITRO -- not installed --
>> MINOPF -- not installed --
>> MOSEK -- not installed --
>> PDIPMOPF Version 5.0 17-Dec-2014 PCWIN64
>> SCPDIPMOPF Version 5.0 17-Dec-2014 PCWIN64
>> SDPT3 -- not installed --
>> SeDuMi -- not installed --
>> TRALMOPF Version 5.0 17-Dec-2014 PCWIN64
>> Architecture: PCWIN64
>> <mpc123.mat>
>
