You would have to do the math and verify this, but the only way I can think of to make the Q losses zero is to eliminate any charging capacitance in the line and set bus voltage magnitudes to 1 p.u.
-- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Apr 17, 2013, at 7:35 AM, Aftognosia Aftognosia <[email protected]> wrote: > When we set R=0, it makes power losses =0 > What I am trying to accomplish is to see the power flows (P,Q) through the > lines, but without considering losses. > DCOPF does not show the Q flows in the lines. So I want a ACOPF. > > In other words, say we have a bus with one generator. We have also a load of > 100MW, 100MVAr. So the generator produces 100MW and 100MVAr (ie no P , Q > losses) . There are 2 lines from the generator bus and say that the flow from > each line is 50MW, and 50MVAr. And we also get the |V| and the voltage > angles as well. > > This is what I want. To see the flows through the lines, without considering > P losses and Q losses. > By setting R=0, we accomplish the first objective: not to have P losses. > How can I make Q losses zero as well? > > Thank you > > > > From: Ray Zimmerman <[email protected]> > To: MATPOWER discussion forum <[email protected]> > Sent: Tuesday, April 16, 2013 9:58 PM > Subject: Re: Ignoring losses > > I find it difficult to believe that setting R=0 makes the real power *flows* > zero … I assume you meant real power *losses*. > > I'm not sure what you are trying to accomplish … but I agree that setting X = > 0 is not going to be realistic. I'm not sure there is a "realistic" model > where voltages are not 1 and reactive losses are zero. But this is not > strictly a MATPOWER question and should probably be addressed in another > forum. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Apr 16, 2013, at 2:53 PM, Aftognosia Aftognosia <[email protected]> > wrote: > >> Dear Dr Zimmerman, >> >> By setting r=0 , for the branches, the real power flows are zero. >> But the reactive power flows are not zero. >> When I set X=0, the voltage magnitudes become 1, and generally the results >> are not realistic. >> >> How can I set the Reactive power losses = 0 ? >> >> I would not like to move to DCOPF, because this formulation ignores Q flows, >> and sets voltage magnitudes=1. >> >> Thank you >> >> From: Ray Zimmerman <[email protected]> >> To: MATPOWER Discussion List <[email protected]> >> Sent: Tuesday, April 9, 2013 7:37 PM >> Subject: Re: Ignoring losses >> >> One way is to simply zero out the R data for the branches … >> >> define_constants; >> mpc = loadcase('mycase'); >> mpc.branch(:, BR_R) = 0; >> r = runopf(mpc); >> >> Another is to simply use a DC OPF which is based on a lossless, linear >> approximation of the network model. >> >> r = rundcopf(mpc); >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> >> On Apr 5, 2013, at 11:28 PM, Aftognosia Aftognosia <[email protected]> >> wrote: >> >>> Hello. >>> Congratulations for this list and for the matpower community ! >>> >>> I am trying to formulate an OPF problem on matpower. >>> I receive the results but I would like to ignore losses! >>> >>> I.e. I am giving the data for r and for x , but I would like to ignore the >>> losses. >>> How can I ignore the losses please? >>> >>> Thank you >>> John Eaftos >>> NTUA >>> >> >> >> > > >
