I’m afraid I do not know exactly what characteristic of your system results in this issue for larger loads. Attempting with a different solver is certainly worth a try. It is possible that the problem becomes infeasible (e.g. due to voltage and reactive power limits being exceeded) when the load increases.
-- Ray Zimmerman Senior Research Associate B30 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Dec 1, 2013, at 3:08 PM, Spyridon Gian <[email protected]> wrote: > > I have created a 10 bus radial network, with line resistance = 0.06 pu, and > Line reactance = 0.02 pu , for each line. > The load is 13.6 kW , for each of 6 buses. The remaining 4 buses have no > load. > There is only 1 generator and is connected to bus 1. > I run the OPF, and the result is the following: > > MATPOWER Version 4.1, 14-Dec-2011 -- AC Optimal Power Flow > MATLAB Interior Point Solver -- MIPS, Version 1.0, 07-Feb-2011Warning: Matrix > is close to singular or badly scaled. Results may be inaccurate. RCOND = > 9.951817e-19. > > In mips at 422 > In mipsopf_solver at 145 > In opf_execute at 106 > In opf at 225 > In runopf at 96 > > Numerically Failed > > Did not converge in 7 iterations. > > Did not converge (0.10 seconds) > > The interesting thing is that the OPF converges at the exact same network, > after one and only one change: > If the load becomes less than 13.5 kW ! Eg. If I run the OPF using a load of > 2.9kW , it converges! > > 1. Can you give me an explanation of the reason why this occurs? > 2. Is there a way to avoid it ? Eg by choosing another solver perhaps? > > Thank you
