That is very strange … are you certain you are using an unmodified version of the latest MATPOWER, including case14.m? You might just double-check by downloading a fresh distribution and trying it with those files.
It should not solve because there is an isolated PV bus, with no way to compute the voltage angle at that bus. -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Apr 5, 2013, at 5:34 AM, ahmad rezaee <[email protected]> wrote: > Dear D zimmerman > > Please see below. It shows the success of power flow during the outage of > line 14. > > mpc=loadcase('case14'); > >> mpc.branch(14,11)=0; > >> r=runpf(mpc) > > r = > > version: '2' > baseMVA: 100 > bus: [14x13 double] > gen: [5x21 double] > branch: [20x17 double] > gencost: [5x7 double] > order: [1x1 struct] > et: 0.0060 > success: 1 > > >> r.success > > ans = > > 1 > > > Kind Regards > > Ahmad > > > From: Ray Zimmerman <[email protected]> > To: MATPOWER discussion forum <[email protected]> > Sent: Thursday, April 4, 2013 7:59 AM > Subject: Re: outage of line 14 in IEEE 14 bus test system > > >> define_constants > >> mpc = loadcase('case14'); > >> mpc.branch(14, BR_STATUS) = 0; > >> opt = mpoption('OUT_ALL', 0); > >> r = runpf(mpc, opt); > > MATPOWER Version 4.1+, 28-Nov-2012 -- AC Power Flow (Newton) > Warning: Matrix is singular to working precision. > > In newtonpf at 109 > In runpf at 224 > > <warning repeated 9 more times> > > Newton's method power did not converge in 10 iterations. > >> r.success > > ans = > > 0 > > The results are telling you that the power flow did not converge (that is, it > was unable to find a solution) … and that information is "correct and > reliable" ;-) … so, no, any bus voltages, flows, etc will not correspond to > a solved power flow. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Apr 4, 2013, at 4:55 AM, ahmad rezaee <[email protected]> wrote: > >> Dear Dr Zimmerman >> >> In IEEE 14 bus test system when I make out line 14 and run power flow, >> matpower messages: "Warning: Matrix is singular to working precision.". >> This message means that jacobian matrix is singular. Yes? Matpower gives me >> some results for power flow. Are the results correct and reliable? (I know >> this problem occurs since bus 8 will be islanded.) >> >> Kind regards >> >> Ahmad > > >
