Dear Ray, Thank you very much! It is a very smart way to deal with that. How could I not realize that in the first place? Thank you very much!
Kind regards, Jin 2018-04-20 4:51 GMT+10:00 Ray Zimmerman <[email protected]>: > Dear Jin, > > In response to your original question. You are correct. However, if the > flow limit is binding (which it is when the shadow price is non-zero), then > the apparent power flowing in the line is equal to RATE_A. So I just use > RATE_A since it is readily available. > > Ray > > > > On Apr 12, 2018, at 11:45 PM, Ma Jin <[email protected]> wrote: > > Dear Sarmad, > > Thank you very much! The caveats pointed by you are really helpful. > Thanks! > > Kind regards, > Jin > > 2018-04-13 13:16 GMT+10:00 Sarmad Hanif <[email protected]>: > >> Dear Jin, >> >> Yes, you are right. >> >> >> >> However according to my experience, you have to be careful regarding the >> calculation of Jacobian of voltage sensitivities which might be required to >> translate Lagrange multipliers to LMP components. >> >> Matpower can give these sensitivities (Jacobian) from the function >> makeJac(). >> >> So if you calculate Jacobian like makeJac(mpc), then it will give you >> sensitivity at the base case. >> >> Hence to get the updated Jacobian (representing the operating >> conditions), you need to implement something like makeJac(results_pf), >> where results_pf = runpf(mpc). >> >> Another issue, which I believe was corrected by Ray, was that if you have >> generators in the grid they were taken by-default as PV while making the >> Jacobian. So you might need to get the updated version of MATPOWER. >> >> Maybe Ray could shed some more light on making sure the steps for >> correctly translating Lagrange multipliers to LMP components. >> >> >> >> Hope it helps. >> >> Best, >> >> Sarmad >> >> *From:* [email protected] [mailto: >> [email protected]] *On Behalf Of *Ma Jin >> *Sent:* Wednesday, 11 April, 2018 5:24 PM >> *To:* MATPOWER discussion forum >> *Subject:* Re: Question about shadow price of line flow constraints in >> AC OPF >> >> >> >> Dear Sarmad, >> >> >> >> Thanks! Matpower provides the values of all Kuhn-tucker multipliers and >> Lagrange multipliers. So it is really a powerful tool which makes >> decomposition of the price possible if one wants to. >> >> >> >> Kind regards, >> >> Jin >> >> >> >> 2018-04-11 17:12 GMT+10:00 Sarmad Hanif <[email protected]>: >> >> Hi Jin, >> >> I couldn’t understand the issue you reported. But according to my >> knowledge, MATPOWER gives you the final price at the node, it doesn’t >> calculate individual congestion, loss, energy components. >> >> Moreover, for ACOPF, MATPOWER gives you and active ($/MW) and reactive >> power ($/MVar) marginal prices at respective nodes. >> >> Hope it helps. >> >> >> >> *From:* [email protected] [mailto: >> [email protected]] *On Behalf Of *Ma Jin >> *Sent:* Wednesday, 11 April, 2018 8:04 AM >> *To:* [email protected] >> *Subject:* Question about shadow price of line flow constraints in AC OPF >> >> >> >> Dear all, >> >> >> >> I feel confused about the unit of the shadow price of the line flow >> constraints in AC based OPF. Since the square of the apparent power is used >> when building the line flow constraints, the shadow price should be with a >> unit of $/(MVA*MVA). When it is converted to the shadow price $/MVA, >> MatPower times the RateA of that line, but for me, it more makes sense if >> it is multiplied with the apparent power flowing through the line. What is >> the reason behind multiplying that RateA. Thanks! >> >> >> >> Kind regards, >> >> Jin >> >> >> > > >
