The power flow solver does not redispatch generation in order to respect the line flow limits specified in branch(:, RATE_A). For that, you will need to use the OPF.
-- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Jan 12, 2012, at 8:13 AM, iman wrote: > > > Dear Arash,Dear all, > > > > I-I read the power flow from line 1 to 2 and from line 1 to 3.After making > all the loads double, we have 154.81 and 81.74 MW for them respectively > (Baring in mind that they were 10.89 and 15.08 MW). Does that make sense? > > > > II-I changed rate A or B or C from 133 to 60 but again got the same power > flow on branches 1-2 and 1-3. > > > > III-If I am not able to do it by changing certain values, does anyone has a > reference to introduce to me in which I can calculate Line Thermal Limits > from x, r ,w ? > > > > Thank you for your help > > > > > > On Wed, Jan 11, 2012 at 7:34 PM, Arash Alimardani <[email protected]> > wrote: > I guess the thermal limit constraint is satisfied in your case (236.55 MW). > Firstly, you have to read the power flow through the line, not the injected > power in one bus. > Secondly, as I remember, the column rateA in the branch matrix for each case > is the thermal limit of that line. > In your case, the slack is connected to bus 2 and bus 3, which provides it > with 260 MW capacity of transmitting power. > > Regards > > > On Wed, Jan 11, 2012 at 8:57 AM, iman <[email protected]> wrote: > Dear all, > > > > I want to use power flow (PF) for the load increase studies. I picked 30 bus > system with Pg=23.54 MW for the slack bus. Running the power flow with the > base loads ,I get 25.97 MW which is quite close to 23.54. > > Now I want to increase all of the loads 2 times. Running pf I get 236.55 MW > for the slack bus . > > I think in practice thermal line limits doesn’t allow this amount of power > dragging from slack bus. > > I want to make my problem practical by imposing thermal limits on the > branches .How can I do that? > > > > Thank you in advance for your patience > > I look forward to hear from you guys > > Iman > > > > > > -- > Best regards > Iman >
