Thank you very much. Is it possible for you to give an example, for example case9, for all generators? I will be appreciate if you do it.
Best Regards R. Carvalini On Mon, Mar 14, 2011 at 16:08, Ray Zimmerman <[email protected]> wrote: > The *A* matrix is from equation (5.25) in the User's > Manual<http://www.pserc.cornell.edu/matpower/manual.pdf>. > As I mentioned, the coefficients need to go in the columns corresponding to > Pg(1) and Qg(1). So, Pg(1) is in the first column following the voltage > angles (1st nb columns) and magnitudes (next nb columns), so it's in column > 2*nb+1. For Qg(1) it's the first column after the Pg columns, so 2*nb (for > the voltage angles and magnitudes) plus ng columns for Pg. > > Yes, if you wanted to do this for all generators, you need to include a row > in *A* for each. Be careful though, this will likely over-constrain the > problem and make it infeasible. If all generators have a fixed power factor, > then balancing the real power output to match the load will mean a specific > reactive power output as well, which will not necessarily match the reactive > power load. > > -- > Ray Zimmerman > Senior Research Associate > 211 Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > On Mar 11, 2011, at 11:40 AM, Roberto Carvalini wrote: > > Thank you very much. > > I have read the manual but I didn't understand by which formula you > computed this matrix (highlighted) > > mpc.A = sparse([1; 1], *[2*nb+1; 2*nb+ng+1]*, [QPratio; -1], 1, > 2*nb+2*ng); > > and if want to define the same PF for all generators, must I repeat this > for all or it depends on the type buses (PV or Slack)? > > Regards > > R. Carvalini > > On Fri, Mar 11, 2011 at 16:27, Ray Zimmerman <[email protected]> wrote: > >> Dirk's suggestion is fine for a simple power flow. But if you want to run >> an OPF, where the generator dispatch is to be determined by the >> optimization, but subject to a constant power factor constraint, then you >> will need to supply an additional user-defined linear constraint. For >> example, if you want to run case9 with a constant power factor constraint of >> 0.95 on the first generator, you could do it like this ... >> >> define_constants; >> mpc = loadcase('case9'); >> nb = size(mpc.bus, 1); >> ng = size(mpc.gen, 1); >> pf = 0.95; >> QPratio = sqrt(1/pf^2 -1); >> %% add constraint that QPratio * Pg(1) - Qg(1) = 0 >> mpc.A = sparse([1; 1], [2*nb+1; 2*nb+ng+1], [QPratio; -1], 1, 2*nb+2*ng); >> mpc.l = 0; >> mpc.u = 0; >> r = runopf(mpc); >> resulting_pf = r.gen(1, PG) / sqrt(r.gen(1, PG)^2 + r.gen(1, QG)^2) >> >> The important part here is defining the A matrix properly, where the >> columns correspond to voltage angles, voltage magnitudes, generator real >> injections, and generator reactive injections (2*nb + 2*ng columns in all). >> So the coefficients for our constraint co in the columns corresponding to >> Pg(1) and Qg(1). >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: <%28607%29%20255-9645>(607) 255-9645 >> >> >> >> On Mar 11, 2011, at 9:50 AM, Dirk Van Hertem wrote: >> >> You model your generator as a load, so it is not represented in your gen >> matrix. Of course, if you want model your generator in a unit commitment, >> this may not be trivial... >> >> Dirk >> >> On 03/11/2011 12:32 PM, Roberto Carvalini wrote: >> >> Thank you >> >> How can I add? my problem is this >> >> Best Wishes >> >> Roberto >> >> >> On Fri, Mar 11, 2011 at 12:22, Dirk Van Hertem >> <[email protected]>wrote: >> >>> You can just define them as a PQ bus with negative power... (negative >>> load) >>> >>> Dirk >>> >>> >>> On 03/11/2011 12:11 PM, Roberto Carvalini wrote: >>> >>>> Hi >>>> >>>> How can I define constant power factor in MAPOWER for example, for >>>> generators PF=0.9? >>>> >>>> Please help me >>>> >>>> Regards >>>> >>>> Roberto >>>> >>>> >>>> >>> >>> -- >>> Dirk Van Hertem [email protected] >>> Electrical Engineering Department http://www.esat.kuleuven.be/electa >>> K.U. Leuven, ESAT-ELECTA GSM: +32-(O)498-61.74.98 >>> 10, Kasteelpark Arenberg, B-3001 Heverlee fax: >>> <%2B32-16-32.19.85> <%2B32-16-32.19.85>+32-16-32.19.85 >>> >>> >>> >> >> >> -- >> Dirk Van Hertem [email protected] >> Electrical Engineering Department http://www.esat.kuleuven.be/electa >> K.U. Leuven, ESAT-ELECTA GSM: +32-(O)498-61.74.98 >> 10, Kasteelpark Arenberg, B-3001 Heverlee fax: >> <%2B32-16-32.19.85>+32-16-32.19.85 >> >> >> >> > > > >
