You should not need to use add_costs. I would suggest using a small constant positive cost for all of the original generators (though zero should work). I'm not sure I've ever tested it, but I believe a polynomial cost for the dispatchable loads should work just fine.
-- Ray Zimmerman Senior Research Associate 211 Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Dec 23, 2010, at 3:58 AM, jrwang wrote: > > Dear All, > > I want to model load curtailment based on AC-OPF by using dispatchable load. > And the objective is to minimize the total amount of active load(deltaPd) > curtailed. > > Do I need to modify the objective using the add_costs methods? Or only set > the cost coefficients of original generators to be zero? > > Another question is: can the negative generator (dispatchable load) use > polynomial cost? > > Thanks! > > ---------------- > Jingran Wang > PhD candidate > Key laboratory of Smart Grid, Ministry of Education > Tianjin University > Tianjin,300072 > China > Work: +86-022-27404221 > E-mail: [email protected], [email protected] > > > >> From: Ray Zimmerman <[email protected]> >> Reply-To: "MATPOWER discussion forum" <[email protected]> >> To: MATPOWER discussion forum <[email protected]> >> Subject: Re: load shedding >> Date:Mon, 1 Nov 2010 13:52:56 -0400 >> >> Yes. Either method works for AC OPF. >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> On Oct 31, 2010, at 2:40 AM, jrwang wrote: >> >>> >>> Are the same techniques suited for load shedding in AC-OPF considering >>> voltage constraints? >>> >>> Thanks! >>> >>>> From: Ray Zimmerman > >>>> Reply-To: "MATPOWER discussion forum" > >>>> To: MATPOWER discussion forum > >>>> Subject: Re: load shedding >>>> Date:Fri, 29 Oct 2010 12:01:46 -0400 >>>> >>>> Both techniques work. You can do as you suggest and simply add a high cost >>>> generator next to the load . Or you can do as Carlos suggests and replace >>>> the load with a dispatchable load at a high price. See section 5.4.2 in >>>> the manual for more details. >>>> >>>> One advantage to the latter is that as the load sheds it maintains a >>>> constant power factor. >>>> >>>> -- >>>> Ray Zimmerman >>>> Senior Research Associate >>>> 211 Warren Hall, Cornell University, Ithaca, NY 14853 >>>> phone: (607) 255-9645 >>>> >>>> >>>> >>>> On Oct 29, 2010, at 12:21 AM, Mehdi wrote: >>>> >>>>> Hi there, >>>>> >>>>> Can anybody help me with how can I consider load shedding in MATPOWER's >>>>> dc-opf ? >>>>> >>>>> Can I model load shedding as active power only generator (Pg=0, >>>>> Pgmax=Load at that bus, Qg,Qgmax=0) at load buses? Then by running the >>>>> dc-opf the output of these generator can be considered as load shedding!!! >>>>> >>>>> Regards, >>>>> Daniel >>>> >>>> >>> >>> >> >> >>
