Can you accomplish what you want simply by including the base dispatch in the 
PD column of the bus matrix (where injections would appears as negative loads)?

-- 
Ray Zimmerman
Senior Research Associate
B30 Warren Hall, Cornell University, Ithaca, NY 14853  USA
phone: (607) 255-9645

On Aug 28, 2014, at 10:10 PM, vids <[email protected]> wrote:

> Thank you very much, Dr. Shri. Yes i think your suggestion about
> making the delta Pg as the control variables is a great idea. However
> I am new to Matpower. Can you help me/ direct me to some examples on
> how i can accomplish this? Thank you very much...
> 
> On Thu, Aug 28, 2014 at 12:23 AM, Abhyankar, Shrirang G.
> <[email protected]> wrote:
>> Vids,
>>  Implementing your reformulated OPF equations, written in complementarity
>> form, is non-trivial in MATPOWER as it will require modifying the
>> variable/equation sizes and muddling with the OPF data structures. Note
>> that you'll also need additional equations, perhaps expressed in
>> semi-smooth form, relating your upward/downward balancing service to
>> generator power deviation. You will have to spend some time to understand
>> the OPF data structures and how they are used in the various OPF routines.
>> 
>> One other possible way (that I think will work) is by using the real power
>> generator deviation \Delta{Pg} as the control variable instead of Pg (see
>> the attached equations).  This will keep the sizes of the
>> variables/equations for the reformulated OPF same as the original one.
>> However, you will have to modify the cost function, gradient, Hessian, and
>> the generator real power limits accordingly.
>> 
>> Shri
>> 
>> -----Original Message-----
>> From: vids <[email protected]>
>> Reply-To: MATPOWER discussion forum <[email protected]>
>> Date: Wed, 27 Aug 2014 16:18:14 +0800
>> To: <[email protected]>
>> Subject: Modifying the Power Balance Equations
>> 
>>> Hi Dr Zimmerman and Matpower Community,
>>> 
>>> I am trying implement an OPF where the real power dispatch is
>>> pre-determined (as in the case of an energy market where the Q
>>> schedules are managed separately by the transmission operator).
>>> 
>>> Is it possible to implement it in Matpower? My idea is to add "slack"
>>> variables in the nodal energy equations
>>> 
>>> Pgi - ΔPgi + Pb1i - Pb2i - Pdi = ΣViVjYij(cos(θij + δi -δj)
>>> 
>>> Pgi  - fixed/predetermined real power generated at node i
>>> ΔPgi - real power 're-scheduling' due to the reactive power dispatch
>>> Pb1i - upward balancing service at node i
>>> Pb2i - downward balancing service at node i
>>> 
>>> Pb1i and Pb2 will have non-zero values when ΔPgi is nonzero, prompting
>>> other generators to compensate the real power 're-scheduling' when
>>> needed.
>>> 
>>> This is the formulation in the dissertation of Dr.  El-Samahy, and I
>>> am wondering if this can be implemented in matpower.
>>> 
>>> Any ideas would greatly be appreciated. Thank you very much.
>>> 
>>> --
>>> 2 Cor 12:9
>>> Each time he said, "My grace is all you need. My power works best in
>>> weakness." So now I am glad to boast about my weakness, so that the
>>> power of Christ can work through me.
>>> 
>>> 
>> 
> 
> 
> 
> -- 
> 2 Cor 12:9
> Each time he said, "My grace is all you need. My power works best in
> weakness." So now I am glad to boast about my weakness, so that the
> power of Christ can work through me.
> 
> 

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