It should be legitimate to set a generator bus as a PQ bus (i.e. turn off any voltage control). This already works as expected I believe.
The bug has to do with the way the voltages are initialized for the AC power flow run. For a generator bus that is set as a PQ bus, it should use the voltage magnitude in bus(:, VM), but it is currently using the voltage from gen(:, VG). For a solved case, the gen(:, VG) value does not contain the solved voltage, so running a power flow with the solved case as the input does not converge immediately as it should. In fact, in this case, it is such a bad starting point that the power flow diverges. -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Mar 14, 2012, at 2:40 PM, Kelly, Michael W. wrote: > Is the reason you are considering a bug for MATPOWER is that the 283 PQ buses > is near the bus limit of the network resulting in little freedom for a > definitive answer, or is there another reason? > > Thanks, > > Mike > > > Michael Kelly, Instructor > Lab FH-449, Office FH-370A > http://sce.umkc.edu/power/suggestedtexts.aspx > University of Missouri – Kansas City > School of Computing & Engineering > Flarsheim Hall, 5110 Rockhill Road, > Kansas City, Missouri 64110-2499 > cell (913) 375-6802 / land-line (816) 235-1254 / fax (816) 235-1260 > ________________________________ > From: [email protected] > [[email protected]] on behalf of Ray Zimmerman > [[email protected]] > Sent: Wednesday, March 14, 2012 1:26 PM > To: MATPOWER discussion forum > Subject: Re: no solution to DC power flow > > You have about 283 generator buses that are marked as PQ buses, rather than > PV buses. This is what is producing the problem with the AC power flow not > converging immediately when run using the solution as an input. I think this > should probably be considered a bug in MATPOWER. > > The other thing is that you have 4 lines with zero reactance. That is where > the NaN's come from in the DC power flow solution. And yes, the DC power flow > is simply the solution of a linear set of equations, so no iteration is > necessary. > >>> find(mpc.branch(:, BR_X) == 0) > > ans = > > 3776 > 3784 > 5471 > 5959 > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 >
