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<http://images.pennnet.com/articles/hrm/cap/cap_coord%2003.gif> 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 >>>>> >>>>> >>>> >>>> >>> >>> >> >> > >
