They are both correct ... it's just that they are giving you different information. The question is, what do you want to know? If you want the losses in the series portion of the model, not counting the line charging, then use get_losses.m. If you want the total net reactive loss in a branch (including the effects of line charging), then use (Qf+Qt).
-- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Mar 10, 2011, at 5:08 AM, Simon Schneider wrote: > Hi everyone, > > I know it´s more a general question, but regarding the following conversation > from the archive, which results are correct? > The (Qf - Q)t or the ones obtained from the get_losses.m file? > I would have done it the same way as mohsen, just with the absolute values, > but now i´m somewhat unsure. > > thank you > Simon > > > ============================================================ > > Ray Zimmerman > Thu, 02 Sep 2010 13:45:38 -0400 > > If I recall correctly, MATPOWER reports the reactive losses in the series > portion of the transmission line not including the line charging elements. As > you noticed, including the line charging elements often makes the total > reactive power "loss" for a line negative. > > -- > Ray Zimmerman > Senior Research Associate > 211 Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > On Aug 26, 2010, at 9:06 AM, mohsen rahmani wrote: > >> Dear all >> >> I already implemented a power flow with Newton method. all my results are >> equal to matpower except reactive power losses. >> >> we can use various formulation for calculating reactive power losses the >> simple one is: >> Q(from-to)+Q(to-from)=Q(losses) but this formulation is not satisfied in >> matpower results. what is the problem? for example for IEEE 30 bus system: >> >> Branch Data >> | >> ================================================================================ >> Brnch From To From Bus Injection To Bus Injection >> Loss (I^2 * Z) >> # Bus Bus P (MW) Q (MVAr) P (MW) Q (MVAr) P (MW) Q >> (MVAr) >> ----- ----- ----- -------- -------- -------- -------- -------- >> -------- >> 1 1 2 10.89 -5.09 -10.86 >> 2.17 0.026 0.08 >> 2 1 3 15.08 4.09 -14.96 >> -5.57 0.127 0.48 >> in branch 1-2 the losses sholud be (-5.09)+(2.17 )= -2.92 >> in branch 1-3 the losses should be (4.09 )+(-5.57 )=-1.46 >> >> which are different from matpower results. >> >> thanks for your help >> Best Regards >> Mohsen Rahmani > > >
