Sorry, I'm afraid you'll have to do you own research to sort out the differences in the other papers and in your model. Apparently, their modeling includes things that are missing from the simple approach you've chosen. It is up to you to understand the implications of the models you choose. I suggested a few possible approaches, but I have no way to know whether my ideas fit with your application. Nor do I have the time to invest in individual applications of MATPOWER to be able to answer these kinds of questions for you.
Best, -- Ray Zimmerman Senior Research Associate 419A Warren Hall, Cornell University, Ithaca, NY 14853 phone: (607) 255-9645 On Feb 23, 2012, at 11:57 AM, Silvio Miceli wrote: > According to your previous answers to my posts the difference is only between > voltage constraints in order to distinguish the results with and without > OLTC. But I expect with OLTC, according to some papers I have read, it > should be greater than that without OLTC. I have confused and I don't know > how can I compare the results? Could you please help me? > > Best Wishes > > Silvio > > > On Thu, Feb 23, 2012 at 17:47, Ray Zimmerman <[email protected]> wrote: > So, the only difference between the two cases are the voltage constraints at > the slack bus? If so, I would expect the losses (and therefore the > generation) to be greater in the case with the lower voltage. > > -- > Ray Zimmerman > Senior Research Associate > 419A Warren Hall, Cornell University, Ithaca, NY 14853 > phone: (607) 255-9645 > > > > > On Feb 23, 2012, at 11:24 AM, Silvio Miceli wrote: > >> Practically I don't have OLTC. According to your comments to my posts: "1) >> Exclude bus GSP and the OLTC from the model and let Tx be the slack bus with >> a dummy generator and VMIN = VMAX = 1.078." So, when I compare the results >> considering OLTC, i.e. constraints of voltage at the slack bus , and without >> any constraint, i.e. Vmax=Vmin=1.06. In my idea, in the case with OLTC and >> lower and limits the capacity should be higher that without constraint? Am I >> right? >> >> Regards >> >> Silvio >> >> >> >> On Thu, Feb 23, 2012 at 17:16, Ray Zimmerman <[email protected]> wrote: >> It's probably due to a difference in losses. There may be losses in the OLTC >> itself depending on the parameters and if the voltage profile is different >> the losses in the rest of the network will be different as well. >> >> -- >> Ray Zimmerman >> Senior Research Associate >> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >> phone: (607) 255-9645 >> >> >> >> >> On Feb 23, 2012, at 11:00 AM, Silvio Miceli wrote: >> >>> Dear Ray, >>> >>> As far as I know when we have an OLTC, the generated capacity is more than >>> that in the case without OLTC (i.e. Vmin=Vmax=1.06 p.u.). When I running an >>> OPF or runmarket, for example in the case57, I get more generated capacity >>> in the case without OLTC compared to with OLTC. >>> >>> Best Wishes >>> >>> Silvio >>> >>> >>> On Mon, Feb 13, 2012 at 16:09, Silvio Miceli <[email protected]> >>> wrote: >>> Thank you so much for your helpful comments. >>> >>> Best Wishes >>> >>> Silvio Miceli >>> >>> >>> >>> On Mon, Feb 13, 2012 at 15:27, Ray Zimmerman <[email protected]> wrote: >>> I don't know what you mean by the first solution with and without the OLTC. >>> In the first solution, I am assuming that the OLTC maintains the voltage at >>> Tx at your target, so it is not in the model. I suppose if by "without >>> OLTC" you mean that the OLTC is not keeping the voltage at the target, then >>> you can simply set the VMIN and VMAX to 1.0 p.u. Or you could use the >>> setup for the 2nd option, and simply run it once with the taps at the >>> nominal setting. >>> >>> -- >>> Ray Zimmerman >>> Senior Research Associate >>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>> phone: (607) 255-9645 >>> >>> >>> >>> >>> On Feb 13, 2012, at 9:19 AM, Silvio Miceli wrote: >>> >>>> Dear Prof. Zimmerman, >>>> >>>> I want to use first solution. It is much more easier than the second one. >>>> In this case, how can I compare the results with and without OLTC? >>>> >>>> Kind regards >>>> >>>> S.M. >>>> >>>> >>>> On Mon, Feb 13, 2012 at 15:07, Ray Zimmerman <[email protected]> wrote: >>>> So it seems you could model it two different ways in MATPOWER. >>>> >>>> 1) Exclude bus GSP and the OLTC from the model and let Tx be the slack bus >>>> with a dummy generator and VMIN = VMAX = 1.078. >>>> 2) Include GSP and the OLTC, with a dummy generator at GSP (the slack >>>> bus), with VMIN = VMAX = 1.0. In this case, you would have to iteratively >>>> run the OPF, then update the tap setting until the voltage at Tx is close >>>> enough to your target. I suppose you could use VMIN = VMAX = 1.078 at Tx >>>> and then adjust the tap ratio until you get a feasible solution. You may >>>> need to leave a small epsilon difference between VMIN and VMAX at GSP or >>>> Tx in order to get feasibility. >>>> >>>> I expect the results for the rest of the system to be (at least nearly) >>>> identical in the two cases. >>>> >>>> -- >>>> Ray Zimmerman >>>> Senior Research Associate >>>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>>> phone: (607) 255-9645 >>>> >>>> >>>> >>>> >>>> On Feb 10, 2012, at 8:32 PM, Silvio Miceli wrote: >>>> >>>>> >>>>> >>>>> The information of the network is as follows: >>>>> >>>>> The one-line diagram of a typical rural section of the Irish 38-kV >>>>> distribution network was shown in above Figure. The feeders are supplied >>>>> by one 31.5-MVA 110/38-kV transformer (capable of handling reverse power >>>>> flows). The voltage at the grid supply point is assumed to be nominal. In >>>>> the original configuration (no DG), the on-load tap changer at the >>>>> substation has a target voltage of 1.078 pu (41 kV) at the busbar, well >>>>> within the +-10% nominal voltage limits of Irish practice. >>>>> >>>>> Best Wishes >>>>> >>>>> Silvio Miceli >>>>> >>>>> >>>>> On Fri, Feb 10, 2012 at 23:07, Ray Zimmerman <[email protected]> wrote: >>>>> You haven't said which bus is your slack bus. Can I assume that it would >>>>> be the one labeled GSP? I don't see a slack generator at that bus. Is the >>>>> OLTC the *only* voltage control you have in the network? Is the voltage >>>>> at GSP fixed? >>>>> >>>>> -- >>>>> Ray Zimmerman >>>>> Senior Research Associate >>>>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>>>> phone: (607) 255-9645 >>>>> >>>>> >>>>> >>>>> >>>>> On Feb 10, 2012, at 2:51 PM, Silvio Miceli wrote: >>>>> >>>>>> I want to have an OLTC at slack bus only in order to control centrally >>>>>> the network voltage (active network) as below figure. How can I compare >>>>>> the results with and without OLTC? with changing tap ratio or with >>>>>> changing voltage setpoints? >>>>>> >>>>>> <image.png> >>>>>> >>>>>> Best Wishes >>>>>> >>>>>> Silvio Miceli >>>>>> >>>>>> >>>>>> On Fri, Feb 10, 2012 at 20:43, Ray Zimmerman <[email protected]> wrote: >>>>>> In order to understand clearly what you are trying to compare, I would >>>>>> need to see the network topology. >>>>>> >>>>>> But, it both cases include the OLTC in the topology and in one case you >>>>>> are modifying the tap ratio to control voltage and in the other you are >>>>>> simply modifying the generator voltage setpoints, then the two solutions >>>>>> will not be equivalent. >>>>>> >>>>>> -- >>>>>> Ray Zimmerman >>>>>> Senior Research Associate >>>>>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>>>>> phone: (607) 255-9645 >>>>>> >>>>>> >>>>>> >>>>>> >>>>>> On Feb 10, 2012, at 10:46 AM, Silvio Miceli wrote: >>>>>> >>>>>>> Dear Ray, >>>>>>> >>>>>>> As far as I know, taking into account the voltage at slack bus as >>>>>>> optimization variable is equal to have an OLTC. So, how can I compare >>>>>>> the results with and without voltage control at slack? Can it be done >>>>>>> either by changing the tap ratio or voltage limits? >>>>>>> Best Wishes >>>>>>> >>>>>>> Silvio Miceli >>>>>>> >>>>>>> >>>>>>> On Thu, Feb 9, 2012 at 18:57, Silvio Miceli <[email protected]> >>>>>>> wrote: >>>>>>> Dear Ray, >>>>>>> >>>>>>> 1. Can I say MATPOWER's OPF considers the power factor angle of >>>>>>> generators as optimization variable? If not, how can I consider as >>>>>>> optimization variable? >>>>>>> >>>>>>> 2. Also, according to one of your replies to a post with regards to >>>>>>> considering the slack bus voltage as optimization variable, why you >>>>>>> want to implement OLTC in MATPOWER? In my idea, considering the slack >>>>>>> bus as optimization variable is equal to have an OLTC and consequently >>>>>>> considering the secondary voltage as optimization variable. Because >>>>>>> usually the OLTC is used in order to control the voltage of slack bus >>>>>>> and in MATPOWER is already considered as optimization variable. If I am >>>>>>> not right, please let me know? >>>>>>> >>>>>>> Best Wishes >>>>>>> >>>>>>> Silvio >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Wed, Feb 8, 2012 at 17:47, Ray Zimmerman <[email protected]> wrote: >>>>>>> On Feb 8, 2012, at 10:01 AM, Silvio Miceli wrote: >>>>>>> >>>>>>>> 1. What kind of generator has been taken into account in MATPOWER in >>>>>>>> Section 5.4.3 of MANUAL in order to consider the capability curve? >>>>>>> >>>>>>> It is simply intended to be a piecewise linear approximation to the >>>>>>> kind of capability curve exhibited by many types of conventional >>>>>>> generators, such as this one from Figure 2 in [1]. >>>>>>> >>>>>>>> 2. I want to minimize losses instead of maximizing social welfare >>>>>>>> considering offers and bids. How can I do it in MATPOWER? >>>>>>> >>>>>>> The answer to this one is readily available in the list archives ... >>>>>>> e.g. >>>>>>> http://www.mail-archive.com/[email protected]/msg00817.html >>>>>>> >>>>>>>> 3. How can I maximize profit for generators in MATPOWER instead of >>>>>>>> maximizing Social welfare? >>>>>>>> Also, by which formula I can obtain profits (for generators), revenue >>>>>>>> and cost in MATPOWER? Could you please address it? >>>>>>> >>>>>>> I'm not aware of a method to maximize profits, since that would involve >>>>>>> an objective that is a function of price, a very unconventional type of >>>>>>> optimization problem. You can compute revenue directly as the product >>>>>>> of quantity and price, and the cost is available in the dispatch matrix >>>>>>> returned by runmarket. See help idx_disp for a description of each >>>>>>> column of the dispatch matrix. >>>>>>> >>>>>>> - Ray >>>>>>> >>>>>>> [1] >>>>>>> http://www.hydroworld.com/index/display/article-display/353952/articles/hydro-review/volume-28/issue-2/feature-articles/system-protection/coordinating-generator-protection-and-controls-an-overview.html >>>>>>> >>>>>>> -- >>>>>>> Ray Zimmerman >>>>>>> Senior Research Associate >>>>>>> 419A Warren Hall, Cornell University, Ithaca, NY 14853 >>>>>>> phone: (607) 255-9645 >>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>> >>>> >>> >>> >>> >> >> > >
