Thank you so much Pro Zimmerman . I appreciate your help. I try to do more research . Regards
Sent from my iPhone On 20 Feb 2012, at 20:42, Ray Zimmerman <[email protected]> wrote: > I'm sorry. I don't really follow what you are attempting to do, but it seems > like your problem is more of a conceptual one rather than a strictly MATPOWER > related one. I suggest you look for help elsewhere in sorting out the design > issues. Then come back if you have specific questions about using MATPOWER to > run power flow or OPF problems. > > Sorry I can't be of more help. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Feb 20, 2012, at 12:33 PM, iman wrote: > >> Dear Prof Zimmerman, >> >> I don't want to use the second scenario so I add an equality constraint >> Pg=Ploss+Pdemand into my optimization program like the following inequality >> constraint (in Matlab). >> >> % calculate the constraint violations 3 >> c = 150-x(3)-x(4); >> if (c<0) >> cons(1) = abs(c); >> end >> >> x(3) and x(4) are the size of added generators and according to the code >> they should be less than 150MW >> >> I hope that it is clear enought. >> Thank you >> ------------------------------------------------------------ >> >> >> On Mon, Feb 20, 2012 at 4:35 PM, Ray Zimmerman <[email protected]> wrote: >> But how do you dispatch the generators to meet load+losses? Solving for >> voltages and losses assumes a solution in which all of the power flow >> equations are satisfied. Either you allow the program to redispatch >> generators according to some optimization (e.g. OPF) or you set the >> generator dispatch yourself and let the power flow find the slack bus >> generation that satisfies the power flow equations. If you are saying you >> don't want it to do that latter and you don't want to use an OPF, how *do* >> you want the generator dispatches to be set in a way that is consistent with >> the power flow equations? >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> >> On Feb 20, 2012, at 10:20 AM, iman wrote: >> >>> Dear Sir, >>> >>> >>> >>> In short, Matpower is used for calculation of voltage magnitude and angles >>> as well as Power losses. My optimizer invokes Matpower in each iteration, >>> gets the values, manipulate the generators locations and sizes and returns >>> the altered values for the next iteration with the updated values. This >>> procedure continues and then I get my compromised optimum results in my >>> optimizer (which is based on heuristic techniques) >>> >>> So you see that I need to solve a power flow but I don't need the >>> optimization. >>> >>> Best regards >>> >>> On Mon, Feb 20, 2012 at 2:57 PM, Ray Zimmerman <[email protected]> wrote: >>> It is not clear what you would like to use MATPOWER to accomplish? If you >>> don't want to solve a power flow (with specified generation everywhere >>> except the slack bus) and you don't want to solve an OPF where the dispatch >>> is computed by an optimization, what is it that you want it to solve. >>> Specifically, which variables are known and what are you trying to solve >>> for? >>> >>> -- >>> Ray Zimmerman >>> Senior Research Associate >>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>> phone: (607) 255-9645 >>> >>> >>> >>> >>> On Feb 20, 2012, at 9:41 AM, iman wrote: >>> >>>> Dear Prof Zimmerman, >>>> >>>> Thank you for your reply. >>>> Yes I can use OPF for fixining slack bus to constant power but the problem >>>> is that I don't want Matpower give me the optimum solution. I have my own >>>> hueristic optimizer asscioated with matpower so I dont want my optimizer >>>> be affected by Matpower OPF. >>>> So breifly 1- Is there any way to disable simple PF capabilty of slack bus >>>> power compensation? >>>> 2-Or maybe using OPF without minimizng anything (without minimizng >>>> objective functions) such as a void function? As far as I know from: " >>>> http://www.mail-archive.com/[email protected]/msg01379.html"; I >>>> need to change opf_costfcn.m or some other files.Is it correct?Is this >>>> approach feasible? >>>> >>>> Thank you for your time >>>> Best regards >>>> >>>> On Fri, Feb 17, 2012 at 3:15 PM, Ray Zimmerman <[email protected]> wrote: >>>> When running a simple power flow, the slack bus must provide *all* of the >>>> power needed make up the difference between the load+losses and the sum of >>>> the other generators. It cannot be restricted without changing the other >>>> generator dispatches, but then it isn't a simple power flow problem >>>> anymore, but rather some sort of re-dispatch problem (of which an OPF is >>>> one kind). >>>> >>>> So in MATPOWER the PMAX column of the gen table is only used for OPF >>>> problems. >>>> >>>> -- >>>> Ray Zimmerman >>>> Senior Research Associate >>>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>>> phone: (607) 255-9645 >>>> >>>> >>>> >>>> >>>> On Feb 16, 2012, at 4:35 PM, iman wrote: >>>> >>>>> Dear all, >>>>> >>>>> >>>>> >>>>> Supposedly DNO doesn’t allow us to import more than 30 MW from the >>>>> network (and if we do we would be charged), is there any way to limit the >>>>> power coming from the slack up to 30 MW ? >>>>> >>>>> I can see that there is a maximum real power output (MW) designated in >>>>> column 9 of Generator Data (mpc.gen); however when I increase the load >>>>> by running pf I can see P Generation from bus 1 is 127 MW ,no matter what >>>>> the value of “maximum real power output” is. >>>>> >>>>> How can I solve this problem? >>>>> >>>>> >>>>> -- >>>>> Best regards >>>>> Iman >>>>> >>>> >>>> >>>> >>>> >>>> -- >>>> Best regards >>>> Iman >>>> >>> >>> >>> >>> >>> -- >>> Best regards >>> Iman >>> >> >> >> >> >> -- >> Best regards >> Iman >> >
