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]
> <mailto:[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]>
> [mailto:[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
>
>
>
>
