The cost will be the standard generator cost (of Pg) plus whatever user-defined
cost you add (see section 6.3.3 in the manual). So you may have to construct
your user-defined cost portion as your desired total cost minus the standard
generator cost.
I’m afraid I can’t help you with more specifics without the details of your
formulation.
Ray
> On Apr 9, 2019, at 4:56 PM, Jubeyer Rahman <[email protected]> wrote:
>
> I am really sorry that I haven't been able to make it more clear. However, I
> will come up with a clear formulation later on.
>
> Actually, I have already formualted that and am getting some value for R. But
> I am not quite sure whether I have been able to get the cost formulation
> correct.
>
> So, for now , can you only tell me, that if I do get some value for R, which
> is supposed to come from some certain generator's, how can I make that
> calculated as a total power generation Pg+R from the gencost information and
> not from the reserve cost.
>
> On Tue, Apr 9, 2019 at 4:50 PM Ray Zimmerman <[email protected]
> <mailto:[email protected]>> wrote:
> I’m afraid I still don’t understand the problem you intend to solve. The
> formulation you provided is completely equivalent to the standard OPF with
> some additional variables and constraints that have no effect ultimately
> (since r_i = 0 is feasible).
>
> It sounds like you want to apply some kind of constraint to Pg to restrict
> redispatches from some initial dispatch or something, but the formulation you
> provided does not accomplish that.
>
> So, it seems like the first step would be to get the problem formulation
> clear and correct, then we can help if you have questions about the
> implementation.
>
> Ray
>
>
>> On Apr 9, 2019, at 4:33 PM, Jubeyer Rahman <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Yes, I don't want the objective function to be affected in that way. The
>> reason of formulating that way is if I don't have all the generators active
>> in my system (in case I loose one generator for example, I want the rest of
>> the generator's to respond in a certain way).
>>
>> On Tue, Apr 9, 2019 at 4:30 PM Ray Zimmerman <[email protected]
>> <mailto:[email protected]>> wrote:
>> I think there must be something missing. Because the addition of these
>> variables and constraints will not affect the OPF solution at all. It will
>> be the same as the standard OPF formulation with no reserves. That is, the
>> original solution will still be both optimal (since there is no change to
>> the objective function in (6.34)) and feasible (since r_i = 0 is feasible
>> and imposes no additional restrictions on the problem).
>>
>> Your formulation as stated includes no reason for r_i to be non-zero.
>>
>> Ray
>>
>>
>>
>>> On Apr 9, 2019, at 3:33 PM, Jubeyer Rahman <[email protected]
>>> <mailto:[email protected]>> wrote:
>>>
>>> Ok. Here they go:
>>>
>>> similar to 7.2
>>>
>>> 0<=r_i<=Pmax
>>>
>>> for 7.3: Since I don't want the cost to be calculated separately, I don't
>>> need anything here (reserves from generators should be calculated as the
>>> total power generation cost, no separate cost for generator)
>>>
>>> for 7.4
>>> pg^i+x*r_i<=pg^i,max
>>>
>>> x is given as parameters here.
>>>
>>> for 7.5; since I don't have zonal requirement I don't have anything for
>>> that.
>>>
>>> Let me know if you need anything for more clarification.
>>>
>>>
>>>
>>> On Tue, Apr 9, 2019 at 3:13 PM Ray Zimmerman <[email protected]
>>> <mailto:[email protected]>> wrote:
>>> Ok, so you are attempting to modify the existing fixed reserves
>>> implementation to something with a similar, but not identical structure. I
>>> think I need to fully understand the formulation. Can you provide the
>>> equivalent of equations (7.2)–(7.5) for your problem so I can see exactly
>>> where the differences are?
>>>
>>> Ray
>>>
>>>
>>>> On Apr 9, 2019, at 11:43 AM, Jubeyer Rahman <[email protected]
>>>> <mailto:[email protected]>> wrote:
>>>>
>>>> Ok. Thanks a lot for your reply.
>>>>
>>>> What I am trying to implement is something like this 'Pg+x*R', where 'Pg'
>>>> is real power generation, x is a collection of factors (parameters)
>>>> usually fraction number ranging between 0 and 1, and R will be a variable
>>>> for reserves. Usually the minimum value for R is 0 and maximum value is
>>>> equal to the 'Pmax' for each generator asked to provide reserves. What I
>>>> also want is that the reserve cost to be ignored ,rather the cost of total
>>>> power generation 'Pg+x*R' should be calculated from the generator cost
>>>> information and not from the reserve costs ( I have tried that by making
>>>> all the reserve costs zero). In addition to these I have no zonal reserve
>>>> requirement ( I have made the constraint deactivated and deleted the
>>>> second row of the mpc.reserves.zones, deactivated mpc.reserves.req and
>>>> also deactivated where 'req' has been implemented).
>>>>
>>>>
>>>> Can you suggest how can how I do it? or do you have any comments on the
>>>> process I am already following?
>>>>
>>>> Just to illustrate more on the reserve cost modification:
>>>>
>>>> For example, I have 'Pg' from a particular generator (generator 1) 5 MW,
>>>> now after implementing the reserve , it is supplying another 1 MW from its
>>>> capacity (it's Pmax is 10 MW). Now what I want is that this (5+1)=6 MW
>>>> generation cost to be calculated by using the polynomial cost information
>>>> from the mpc.gencost section.
>>>>
>>>>
>>>>
>>>> On Tue, Apr 9, 2019 at 10:38 AM Ray Zimmerman <[email protected]
>>>> <mailto:[email protected]>> wrote:
>>>> I think it might help me to have a high-level view of what you are trying
>>>> to accomplish. If you are simply trying to *use* the already implemented
>>>> fixed reserve capability, you shouldn’t need to even concern yourself at
>>>> all with the implementation (i.e. the Ar matrix and the various callback
>>>> functions, etc.). In that case, all you need is to understand the inputs
>>>> in Table 7-5. If, on the other hand, you are modifying the implementation
>>>> to do something other than what is currently implemented, then I need to
>>>> understand what that is.
>>>>
>>>> In what is already implemented, the generation cost is simply the cost of
>>>> Pg. There is a separate cost of R that is added as a user cost. See (7.3).
>>>> So the cost coefficients of R are provided in mpc.reserves.cost (see Table
>>>> 7-5).
>>>>
>>>> Ray
>>>>
>>>>
>>>>
>>>>> On Apr 8, 2019, at 2:39 PM, Jubeyer Rahman <[email protected]
>>>>> <mailto:[email protected]>> wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> I have another few questions regarding the addition of the fixed zonal
>>>>> reserves. So, far I understand, after adding the reserves, the real power
>>>>> output of the generator will be added with reserve amount, so in the part
>>>>> of the objective function where real power cost is being calculated,
>>>>> which power is fed into as for calculation is it the 'Pg' part of 'Pg+R'
>>>>> or is it the total 'Pg'?
>>>>>
>>>>> If I want to implement a reation like 'Pg+x*R' , where x is a collection
>>>>> of parameters (n-by-1) , which place can I feed into these parameters? I
>>>>> am assuming, this should be the second column of the Ar matrix. Is that
>>>>> correct?
>>>>>
>>>>> Regards
>>>>>
>>>>>
>>>>>
>>>>> On Fri, Apr 5, 2019 at 10:53 AM Jubeyer Rahman <[email protected]
>>>>> <mailto:[email protected]>> wrote:
>>>>> Please ignore the last email, I have figured this out. Every column in
>>>>> the first row corresponds the generators supposed to participate in the
>>>>> reserve provision , that's why they are made one.
>>>>>
>>>>> On Wed, Apr 3, 2019 at 5:27 PM Jubeyer Rahman <[email protected]
>>>>> <mailto:[email protected]>> wrote:
>>>>> Are you talking about the columns in the second row?
>>>>>
>>>>> On Mon, Apr 1, 2019 at 5:21 PM Ray Zimmerman <[email protected]
>>>>> <mailto:[email protected]>> wrote:
>>>>> The only thing you need to do is make sure the corresponding column in
>>>>> mpc.reserves.zones is all zeros.
>>>>>
>>>>> Ray
>>>>>
>>>>>> On Apr 1, 2019, at 10:31 AM, Jubeyer Rahman <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>>
>>>>>> Ok, I got your point and realized my mistake in understanding the zone
>>>>>> handling section. So, if I want some of the generator's choosing not to
>>>>>> provide ramp, should just setting the element of Identity matrix's
>>>>>> corresponding rows of first column of Ar be Ok? or I may need to change
>>>>>> something else as well?
>>>>>>
>>>>>> On Mon, Apr 1, 2019 at 9:45 AM Ray Zimmerman <[email protected]
>>>>>> <mailto:[email protected]>> wrote:
>>>>>> Regarding your first question, as described by (7.2) in the User’s
>>>>>> Manual, the reserve for a given generator is bounded above by both any
>>>>>> limit provided in mpc.reserves.qty (r_i^{max}) and by any physical ramp
>>>>>> rate (∆_i) given in mpc.gen(:, RAMP_10). It just so happens that the
>>>>>> example in t_case30_userfcn does not specify any physical ramp rates,
>>>>>> but the code still needs to handle cases which *do* provide physical
>>>>>> ramp limits.
>>>>>>
>>>>>> I’m not sure why you say only two generators are supposed to take part
>>>>>> in the reserve provision. In t_case30_userfcn there are two reserve
>>>>>> zones defined, but all 6 generators are able to participate in providing
>>>>>> the required reserves.
>>>>>>
>>>>>> You may want to review carefully the formulation in (7.2)–(7.5) and
>>>>>> Table 7-2.
>>>>>>
>>>>>> Ray
>>>>>>
>>>>>>
>>>>>>
>>>>>>> On Mar 29, 2019, at 4:06 PM, Jubeyer Rahman <[email protected]
>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>
>>>>>>> Referring to the 'userfcn_reserves_formulation', there is a line which
>>>>>>> is finding the value of k, which seems to be zero since none of the
>>>>>>> data in 'Ramp_10' column in t_case_30_userfcn is all zeros. so I
>>>>>>> don't see any point of using the line
>>>>>>>
>>>>>>> Rmax(k)=mpc.gen(k,Ramp_10), can you explain why the code is written
>>>>>>> that way.
>>>>>>>
>>>>>>> From my understanding only two generators are supposed to take part in
>>>>>>> the reserve provision, but the while putting the value for Rmax and
>>>>>>> Rmin, the code is considering all of them, which looks kind of
>>>>>>> unreasonable to me. Can you please explain this section as well?
>>>>>>>
>>>>>>> Regards,
>>>>>>> Jubeyer
>>>>>>>
>>>>>>> On Fri, Mar 29, 2019 at 12:43 PM Ray Zimmerman <[email protected]
>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>> That is correct. All of the callbacks are technically optional.
>>>>>>> Typically you need the formulation callback to implement the actual
>>>>>>> problem modifications, and possibly ext2int and int2ext if you need to
>>>>>>> do some handling of input and output data, respectively. The printpf
>>>>>>> and savecase callbacks are only needed if you want to add things to the
>>>>>>> standard pretty-printed output or saved case data.
>>>>>>>
>>>>>>> Ray
>>>>>>>
>>>>>>>
>>>>>>>> On Mar 29, 2019, at 12:15 PM, Jubeyer Rahman <[email protected]
>>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>>
>>>>>>>> Just how important it is to include printpf and savecase callback
>>>>>>>> during the extension of OPF, if I don't really need anything printed
>>>>>>>> out right after I call the power flow? Will it be still possible to
>>>>>>>> extract information from the 'results' when I say
>>>>>>>> results=runopf(mycase)?
>>>>>>>>
>>>>>>>> To my understanding, after runopf being called, 'results' struct will
>>>>>>>> be returned and can be accessed by writing some command like
>>>>>>>> results.gen(:,2), etc. Let me know if I am thinking correctly or not?
>>>>>>>>
>>>>>>>> On Fri, Mar 29, 2019 at 9:53 AM Jubeyer Rahman <[email protected]
>>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>> Thank you very much.
>>>>>>>>
>>>>>>>> On Fri, Mar 29, 2019 at 8:43 AM Ray Zimmerman <[email protected]
>>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>> Are you attempting to use the provided extension for fixed reserves,
>>>>>>>> or are you attempting to write your own extension?
>>>>>>>>
>>>>>>>> If it’s the former, the full implementation is included in
>>>>>>>> toggle_reserves()
>>>>>>>> <http://www.pserc.cornell.edu/matpower/docs/ref/matpower6.0/toggle_reserves.html>.
>>>>>>>> Simply load your case file, use toggle_reserves() to enable the
>>>>>>>> callbacks, then run the OPF (or just call runopf_w_res()
>>>>>>>> <http://www.pserc.cornell.edu/matpower/docs/ref/matpower6.0/runopf_w_res.html>,
>>>>>>>> which does these 3 steps automatically for you).
>>>>>>>>
>>>>>>>> If you are attempting to write your own extension, I suggest making a
>>>>>>>> copy of toggle_reserves.m and rename it and all of the functions in it
>>>>>>>> and use it as a template for your own extension.
>>>>>>>>
>>>>>>>> Ray
>>>>>>>>
>>>>>>>>
>>>>>>>>> On Mar 28, 2019, at 12:40 PM, Jubeyer Rahman <[email protected]
>>>>>>>>> <mailto:[email protected]>> wrote:
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> Recently I was digging through the extending OPF chapter of Matpower
>>>>>>>>> manual, but I don't quite catch the process. Regarding the example
>>>>>>>>> given there on 'Fixed zonal reserves' what I understand from my
>>>>>>>>> reading is, it is required to write down a call back function for
>>>>>>>>> formulation along with some call of callback functions. I have
>>>>>>>>> followed every steps mentioned there but could not make the code run
>>>>>>>>> (I am using version 6.0). I am adding my code snippet here for better
>>>>>>>>> conveying.
>>>>>>>>>
>>>>>>>>> %%%
>>>>>>>>> mpc=loadcase('case30.m');
>>>>>>>>> mpopt = mpoption('out.all', 0, 'verbose', 0);
>>>>>>>>> mpc=add_usefcn(mpc,'formulation',@userfcn_reserves_formulation);
>>>>>>>>> mpc=ext2int(mpc,mpopt);
>>>>>>>>> results=runopf(mpc);
>>>>>>>>> results=int2ext;
>>>>>>>>>
>>>>>>>>> %%%%
>>>>>>>>> Error message:
>>>>>>>>> Access to an object's fields is only permitted within its methods.
>>>>>>>>>
>>>>>>>>> I have added the mpc.reserve data(cost, req, zones) posted in
>>>>>>>>> 't_case30_userfcns.m' file.
>>>>>>>>> I have written the userfcn_reserves_formulation in a different script
>>>>>>>>> , but it is not working.
>>>>>>>>> I didn't write the add_var and add_constraint explicitly since the
>>>>>>>>> add_userfcn callback function already contains those.
>>>>>>>>>
>>>>>>>>> Can you tell me what I am missing?
>>>>>>>>>
>>>>>>>>> Regards,
>>>>>>>>> Jubeyer
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
