Dear professor, I am not familiar with the conceptino of Rate_A Rate_B Rate_C . Can you give me a clue where it is explained?
When I check the mpc.branch(:,RATE_A) in a 14 bus case, I found its value is all 9900 MVA. In your last email, you said the line limit (RATE_A) on lines that are at 100% of their capacity. Do you mean that this capacity (9900 MVA) is so high that there is no congestion cost in the lamda P? Thank you in advance. ________________________________ From: Ray Zimmerman <[email protected]> To: MATPOWER discussion forum <[email protected]> Sent: Thursday, April 4, 2013 10:46 AM Subject: Re: saturation of the branch There are an infinite number of ways to modify the inputs to an OPF to achieve a desired change in the flow of power on a given branch. Each one will result in different set of prices. I'm afraid your problem is not well-defined. Maybe you really want to look at changing the line limit (RATE_A) on lines that are at 100% of their capacity? -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Apr 3, 2013, at 6:00 PM, Yahook K <[email protected]> wrote: Respected Sir, > >Thank you very much for your reply. > >My 3rd question is : I want to change the saturation percentage of a certain branch A (for example, from the original 50% to 120% or 98%)to see its influence to the LMP price of all the buses. That is, I want to see the transmission line congestion impacts on the LMP price. > >How to achieve that? > >In my opinion, to achieve that, I want to change the power demand quantity(PD) of a certain bus B, so that the saturation percentage of branch A will change to 120% or 98%. Then, I runopf to check the Lamda P price and compared the Lamda P price with the previous price when the saturation percentage of branch A is 50%. Am I right? > >Please shed light on me. Thanks. > > > > > > >________________________________ > From: Ray Zimmerman <[email protected]> >To: MATPOWER discussion forum <[email protected]> >Sent: Wednesday, April 3, 2013 9:39 AM >Subject: Re: saturation of the branch > > >Table B-3 in the User's Manual (or help caseformat) describes the fields of >the branch matrix. RATE_A is the limit used by runopf(). Please note that for >an AC power flow model it is an MVA limit, and for DC power flow it is a MW >limit. So that saturation percentage as you call it would be … > > >define_constants; >if <AC power flow> > saturation = sqrt(results.branch(:, PF).^2 + results.branch(:, PT).^2) ./ >results.branch(:, RATE_A); >else > saturation = abs(results.branch(:, PF)) ./ results.branch(:, RATE_A); >end > > > >I'm afraid I don't understand your 3rd question. > > >-- >Ray Zimmerman >Senior Research Associate >419A Warren Hall, Cornell University, Ithaca, NY 14853 >phone: (607) 255-9645 > > > > >On Apr 3, 2013, at 1:18 AM, Yahook K <[email protected]> wrote: > >Respected Sir, >> >> >>From mpc.branch, I can get the From bus injection and the To bus injection of >>each branch. But how can I calculate the saturation percentage of the branch? >>For example, the branch has a limit of 15 MW, and there are 5 MW flowing in >>this branch. I think to calculate the saturation percentage we do 5/15=1/3 >> >> >>Another question is where to find the limit for each branch? >> >> >>The third question would be if I wanna set the branch saturation percentage >>to 50%, 90% 120%, break. How can I do it? Can you give me some guidance? >> >> >>Please shed light on me. Thank you. >> >> >> >> > > >
