See my response to Roberto Carvalini, posted only seconds ago. Am I fast or what? ;-)
-- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Mar 11, 2011, at 10:16 AM, Carlos Gonzalez Almeida wrote: > Thank you very much. > > Could you please give me an example about defining power factor for > generators? > > I cannot set it. > > On Fri, Mar 11, 2011 at 16:09, Ray Zimmerman <[email protected]> wrote: > Carlos, > > If you want the loads to have a power factor of 0.95, you need to set QD such > that PD/sqrt(PD^2 + QD^2) = 0.95, i.e. QD has to equal 0.108 * PD. About the > voltage constraint of 1.5 p.u., I don't see that anywhere, so I'm not sure > what you are referring to. The different lambdas at the two buses are due to > losses. The power factor of the generators is determined by the solution > algorithm within the bounds set for them. That is, each generator has a > feasible "box" defined by PMIN, PMAX, QMIN and QMAX. You don't normally "set" > the power factor of a generator as input to the OPF. I suppose, if for some > reason you have a strict power factor constraint on a generator you could use > some additional linear constraints to the OPF to enforce it, but that would > be unusual I think. > > -- > Ray Zimmerman > Senior Research Associate > 211 Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > On Mar 10, 2011, at 8:10 AM, Carlos Gonzalez Almeida wrote: > >> Another question is this: when I have not fixed loads only I have >> dispatchable loads how can I define power factor for generators and loads >> separately? >> >> Best Wishes >> >> Carlos >> >> On Thu, Mar 10, 2011 at 13:53, Carlos Gonzalez Almeida >> <[email protected]> wrote: >> Dear Prof. Zimmerman >> >> Thanks a lot for your useful guidance. >> >> For example, in the attached file for a simple case study with 2 loads and >> generators I want to have a power factor 0.95. I have problem with adjusting >> power factor in MATPOWER. How can I do it in the attached file? Also I don't >> know why I have voltage constraint 1.5 pu. I think because of these >> constraints I have a little bit difference in the value of lambda >> I have done runmarket with the following offers and bids. >> Could you please tell me why? >> >> +++++++++++++++++++++ >> mpc0 = loadcase('case4gs1'); >> mpc = load2disp(mpc0); >> mkt.OPF = 'AC'; >> offers.P.qty = [100;70]; >> offers.P.prc = [50;100]; >> bids.P.qty = [50 ;70 ]; >> bids.P.prc = [150 ;130 ]; >> [r, co, cb] = runmarket(mpc, offers, bids, mkt); >> co.P.qty >> co.P.prc >> cb.P.qty >> cb.P.prc >> ++++++++++++++++++++++++ >> >> Best Wishes >> >> C. Gonzalez Almeida >> >> >> >> On Wed, Mar 9, 2011 at 19:47, Ray Zimmerman <[email protected]> wrote: >> Carlos, >> >> I'm not sure what you mean by "test the example ... regarding zero power >> factor". If you are going to change some of the existing dispatchable loads >> to have a zero power factor, then the existing market structure for the >> example, which includes only $/MW bids for active power, will not be >> applicable. So you need to decide how you want to handle these reactive-only >> loads. I suppose you'll need to specify reactive power bids for them. >> >> On your second question, the offers and bids are used to construct a gencost >> matrix with negative costs for the negative generators that represent >> dispatchable loads. The objective function is then to minimize this "cost" >> of generation, which is computed in opf_costfcn.m. You are correct that this >> is equivalent to maximizing social welfare. >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> On Mar 8, 2011, at 5:04 PM, Carlos Gonzalez Almeida wrote: >> >>> Dear Dr. Zimmerman >>> >>> -Could you please test the example provided in the manual (t_auction_case) >>> regarding zero power factor. What changes should be carried out? >>> >>> -Moreover, as you know, the objective function obtained in the runmarket is >>> Social welfare. Could you please address me the file that you calculated >>> objective function because I couldn't find it. I want to know in which >>> file (the m file) you have calculated that? >>> >>> Best Regards >>> >>> Carlos >>> >>> >>> >>> On Tue, Mar 8, 2011 at 22:34, Ray Zimmerman <[email protected]> wrote: >>> I'm not really sure without seeing the details of your example. I'm not >>> sure I've ever tested the runmarket code with pure reactive power loads. It >>> would require reactive power bids for those loads, but I'll need the >>> details to be able to help you further. >>> >>> -- >>> Ray Zimmerman >>> Senior Research Associate >>> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >>> phone: (607) 255-9645 >>> >>> >>> >>> On Mar 7, 2011, at 10:42 AM, Carlos Gonzalez Almeida wrote: >>> >>>> Hi >>>> >>>> I am new in MATPOWER abd I want to have zero power factor for example in >>>> example case of manual in runmarket, but several error are occured. please >>>> tell me why >>>> >>>> >>>> Best Wishes >>>> >>>> C. Gonzalez Almeida >>> >>> >>> >>> >>> Best Wishes >>> >>> C. Gonzalez Almeida >> >> >> >> > > > > > Best Wishes > > C. Gonzalez Almeida
