Re: Branch flow limits in OPF
Not without modifying the code. It would involve adding another set of non-linear constraints, which unfortunately is not trivial. It involves modifying the Jacobian and Hessian calculations for constraints as well as modifying the non-linear constraint indexing, which is based on the assumption of only a single set of branch flow constraints. Ray On Mar 26, 2015, at 6:14 PM, Gamze Dogan gamgam...@hotmail.com wrote: Thank you for your answer. Is there a way to limit both current and apparent power? Thank you, Gamze From: r...@cornell.edu Subject: Re: Branch flow limits in OPF Date: Wed, 25 Mar 2015 11:03:03 -0400 To: matpowe...@list.cornell.edu By default, the “flow” constraint in the AC OPF is on apparent power (in the DC OPF, it’s active power), not on current, which probably explains what you are seeing. See the 'opf.flow_lim' option to change the default. Ray On Mar 25, 2015, at 4:55 AM, Gamze Dogan gamgam...@hotmail.commailto:gamgam...@hotmail.com wrote: Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
RE: Branch flow limits in OPF
Thank you for your answer. Is there a way to limit both current and apparent power? Thank you, Gamze From: r...@cornell.edu Subject: Re: Branch flow limits in OPF Date: Wed, 25 Mar 2015 11:03:03 -0400 To: matpowe...@list.cornell.edu By default, the “flow” constraint in the AC OPF is on apparent power (in the DC OPF, it’s active power), not on current, which probably explains what you are seeing. See the 'opf.flow_lim' option to change the default. Ray On Mar 25, 2015, at 4:55 AM, Gamze Dogan gamgam...@hotmail.commailto:gamgam...@hotmail.com wrote: Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
Branch flow limits in OPF
Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
Re: Branch flow limits in OPF
Power flow in a particular line is related to sending end and receiving end voltages as well as line reactance. If you want to increase the power transfer capability on the particular line simply by decreasing the reactance of the line based on degree of series compensation. On Wed, Mar 25, 2015 at 2:25 PM, Gamze Dogan gamgam...@hotmail.com wrote: Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
Re: Branch flow limits in OPF
By default, the “flow” constraint in the AC OPF is on apparent power (in the DC OPF, it’s active power), not on current, which probably explains what you are seeing. See the 'opf.flow_lim' option to change the default. Ray On Mar 25, 2015, at 4:55 AM, Gamze Dogan gamgam...@hotmail.com wrote: Dear all, I have a question regarding the power flow limits in the OPF. The flow is limited by the branch value rateA. I wanted to calculated the pourcentage of flow in my lines after the OPF succeeded. I did it this way: V(d,1) = results.bus(d, 8) * exp(1j * results.bus(d, 9)*pi/180); [Ybus, Yf, Yt] = makeYbus(mpz); Ifrom= Yf*V; pourcentage_line(d) = ( abs(Ifrom) (d) * results.baseMVA) / results.branch(d,6) *100; First, could you tell me if this is correct? Secondly, I have trouble interpreting the results as at the end of my OPF I get pourcentage of flows higher than 100%, for me as the flow has been limited to the rate A value, I sould not get flows higher than 100%. Thank you for any help on the subject, Regards, Gamze
