I’m afraid I still don’t understand what you mean by “minimum and maximum values of real power injection at each bus” … min and max as constrained by what? What are you allowing to vary and what are you keeping fixed?
In the code you provide, it seems like you are taking a particular voltage solution and simply defining the min/max range to be +/- 5% of the injection that would result in the power balance being satisfied for that voltage solution. Ray On Oct 12, 2022, at 12:12 PM, naime ahmadi <naimeahm...@gmail.com<mailto:naimeahm...@gmail.com>> wrote: I need to calculate the minimum and maximum values of real power injection at each bus. Sbus = V .* conj(Ybus * V); P_bus = real(Sbus); Q_bus = imag(Sbus); for i=1:length(P_bus) if P_bus(i)>0 P_inj_max(i,:) = P_bus(i,:)+0.05*P_bus(i,:); P_inj_min(i,:) = P_bus(i,:)-0.05*P_bus(i,:); else P_inj_max(i,:) = P_bus(i,:)-0.05*P_bus(i,:); P_inj_min(i,:) = P_bus(i,:)+0.05*P_bus(i,:); end end for i=1:length(Q_bus) if Q_bus(i)>0 Q_inj_max(i,:) = Q_bus(i,:)+0.05*Q_bus(i,:); Q_inj_min(i,:) = Q_bus(i,:)-0.05*Q_bus(i,:); else Q_inj_max(i,:) = Q_bus(i,:)-0.05*Q_bus(i,:); Q_inj_min(i,:) = Q_bus(i,:)+0.05*Q_bus(i,:); end end On Thu, Oct 13, 2022 at 1:33 AM Ray Daniel Zimmerman <r...@cornell.edu<mailto:r...@cornell.edu>> wrote: I’m afraid I don’t understand what you are trying to calculate. Ray On Oct 11, 2022, at 11:22 AM, naime ahmadi <naimeahm...@gmail.com<mailto:naimeahm...@gmail.com>> wrote: Hello, I want to solve the optimization function for calculating voltage. As a constraint, I need to calculate each bus's minimum and maximum values of real and reactive power injection. here is the calculation: Pfe=branch(:,PF)/baseMVA; Qfe=branch(:,QF)/baseMVA; Pte=branch(:,PT)/baseMVA; Qte=branch(:,QT)/baseMVA; P_inj_max = Pfe+0.05*Pfe; P_inj_min = Pfe-0.05*Pfe; Q_inj_max = Qfe+0.05*Qfe; Q_inj_min = Qfe-0.05*Qfe; Is this way correct? Kind regards, Naime On Tue, Oct 11, 2022 at 1:45 PM naime ahmadi <naimeahm...@gmail.com<mailto:naimeahm...@gmail.com>> wrote: Thank you for your time On Tue, Oct 11, 2022 at 7:14 AM Carlos E Murillo-Sanchez <ce.murillosanc...@gmail.com<mailto:ce.murillosanc...@gmail.com>> wrote: Slight correction: Sf = V( mpc.branch(:, F_BUS) ) .* conj(Yf * V); St = V( mpc.branch(:, T_BUS) ) .* conj(Yf * V); carlos. Ray Daniel Zimmerman wrote: In matrix form, you can do the corresponding calculations as follows (e.g. for case9): define_constants mpc = loadcase('case9'); [Ybus, Yf, Yt] = makeYbus(mpc); V = mpc.bus(:, VM) .* exp(1j * mpc.bus(:, VA)*pi/180); Sbus = V .* conj(Ybus * V); Sf = V .* conj(Yf * V); St = V .* conj(Yt * V); Here Sbus are the bus injections into the branches (equal to the generation – load), and Sf and St are the branch power flows at the from and to ends, respectively. Ray On Oct 10, 2022, at 1:41 AM, naime ahmadi <naimeahm...@gmail.com<mailto:naimeahm...@gmail.com>> wrote: I have forgotten to attach the picture. On Mon, Oct 10, 2022 at 3:40 PM naime ahmadi <naimeahm...@gmail.com<mailto:naimeahm...@gmail.com>> wrote: Hello, I have a question regarding equations (2) and (3) in the attached picture. I am not sure equation (3) is correct. But sj is the power injection and f{i,j} is the power flow. I am a littel bit confused, how should I calculate y*{j,k} and Yjk in Matpower? According to the attached picture y*{j,k} is line adminance vector and Yjk bus adminance matrix. How can I calculate them from Ybus? Thank you, Naime <Capture.JPG>
