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]<mailto:[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]> [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Ma Jin Sent: Wednesday, 11 April, 2018 8:04 AM To: [email protected]<mailto:[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
