I think I should explain the problem more briefly. The thing is that when I input some load to a grid in MATPOWER, the final value of power injections at buses are not exactly equal to the initial values I assigned them. I now know this happens in a real grid due to the branch data (line and/or transformer impedance data), and other loads in the system (if any) that can consume power at each bus when running power flow. So my question is, is it ok to get this result if I run DC power flow in MATPOWER? and I am wondering why this happens. I just want to justify the results.
Thank you so much, Hanie On Fri, Aug 17, 2012 at 9:51 AM, Hanie Sedghi <[email protected]>wrote: > Hello sir, > > Hope you are doing great. > > For my research, I need to feed the grid with independent demands and > follow the outputs. I solve for DC power flow > For changing the demand I use > > mpc = loadcase('case9'); > define_constants; > Nominal_PD =[0;0;13;21.97;0;0;0;0;52.42;0] %something random > > So I expect that Pload in MATPOWER's output be the same as my given > Nominal_PD > which is not always true. > for example I have used case 9 with above Nominal_PD, which is less than > sum of Nominal generations for bus 2,3 (that is 163, 85 respectively) > now Pload=[-3.68;1.83 ;20.53 ;33.52;4.44;3.55 ;4.92 ; -0.56;44.83;-3.02] > > or even when Nominal_PD is such that sum of demand exceeds the generation > in 2,3 (and slack bus compensates for the rest) I have the same problem > that Pload is not equal to Nominal_PD (I assign this value randomly) > > It seems like the grid satisfies demand partially for some nodes and > induces some gen/demand at nodes when there is no demand(when I run DC > power flow) > So I was wondering what is going on here. Is it what in fact happens in > the grid or I am missing an assumption in MATPOWER or is it something else? > > I would truly appreciate your response. > > Best Regards, > Hanie >
