a) Yes. b) It chooses Q so as to minimize the cost of P. c) For a branch, in general the power factor is not known ahead of time, so there is no direct correspondence between an MVA limit (which approximates a current limit) and MW or MVAr limit. (Also, this is not a MATPOWER question … I'm starting to feel like I'm doing your HW for you).
-- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Apr 20, 2013, at 6:38 AM, Aftognosia Aftognosia <[email protected]> wrote: > Dear Dr Zimmerman, > > GeneratorA has a fuel cost of $10/MWh. GeneratorB has a fuel cost of > $12/MWh. GeneratorC has a fuel cost of $14/MWh. > > a) I want to run the OPF, and I created this table. Is it correct? > > mpc.gencost = [ > %n %c(n-1) %co > 2 0 0 2 10 0 ; > 2 0 0 2 12 0 ; > 2 0 0 2 14 0 ; > ]; > > b) How does the program select how much Q each generator will generate, given > that no fuel_cost for Q has been given ? > In other words, for the Generation of P , we added fuel cost in $/MWh. But > for the generation of Q, we did not add such > fuel cost. > > c) RATE_A is the MVA rating for a certain branch. To translate it into MW > rating and MVAr rating we do the following: > MW = MVA * PF_load and MVAr = MVA* PF_load ? (power factor of the load) > Correct? > > > > From: Ray Zimmerman <[email protected]> > To: MATPOWER discussion forum <[email protected]> > Sent: Friday, April 19, 2013 2:32 PM > Subject: Re: line loss > > Since the branch parameters are expressed in p.u. they must be modified along > with baseKV in order for them to represent the same physical parameters. As > it turns out, when the impedance parameters and voltages are expressed in > p.u. (as they are in MATPOWER), there is no effect whatsoever of changing > baseKV of a bus. It is in fact, not needed at all for the power flow > calculations. It's only relevance is as relates to converting p.u. impedances > and voltages back to physical parameters. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Apr 18, 2013, at 3:27 PM, Hedayat Saboori <[email protected]> wrote: > >> Dear all >> I'm about to evaluate the effect of line nominal voltage on line losses. I >> simply increase line connected bus voltages, run power flow, and calculate >> losses. But, in spite of increasing voltage loss is constant in all cases. I >> have developed a simple code for a 2 bus network. M-files are attached. What >> is the problem? does nominal voltage change any thing? >> <case2.m><lineloss.m> > > >
