Unfortunately, I’m not aware of any good method for creating reasonable thermal
limits that does not depend on details of the transmission lines themselves
(voltage level, conductor configuration, etc.).
Ray
> On May 5, 2015, at 12:02 PM, Mari Hardersen Prydz <[email protected]>
> wrote:
>
> Thank you for the clarifying answer. I have one more question I hope you can
> give me some thoughts on.
>
> I'm working with different test cases where some of them have very high
> thermal limits, like case118 and the GBnetwork (Great Britain,
> http://www.maths.ed.ac.uk/optenergy/NetworkData/
> <http://www.maths.ed.ac.uk/optenergy/NetworkData/>).
> I would like to assign more realistic thermal limits to these, but I have
> understood that retrieving correct data is very difficult.
> Is it possible to say anything about what the "normal" thermal limit values
> can be? Or what is realistic considering the share of branches where
> congestion occurs in a network?
>
> Thanks for any help on the subject.
>
> Sincerely,
>
> Mari Prydz
>
>
> On 5 May 2015 at 15:48, Ray Zimmerman <[email protected]
> <mailto:[email protected]>> wrote:
> Hi Mari,
>
> It is only RATE_A that is used by the OPF.
>
> Since the flow at either end of the branch (for AC OPF) are in general not
> equal, there are actually two sets of branch flow constraints, those
> constraining flow at the “from bus” end and those constraining flow at the
> “to bus” end. Usually, if a flow constraint is binding, it is binding only at
> one end, but this is not always the case. In any case, adding the two
> multipliers together should give you the sensitivity of the objective
> function to changes in RATE_A.
>
> Ray
>
>
>> On May 5, 2015, at 6:49 AM, Mari Hardersen Prydz <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Dear all,
>>
>> I'm running the ACOPF on different test cases, and would like to find the
>> effect on the objective function value when changing the thermal limits
>> (rate A, B and C).
>>
>> Firstly, is it only rate A that limits the power flow, or will rate B and C
>> also affect this?
>>
>> So far I have looked at the multipliers MU_SF and MU_ST
>> (bresults.branch(i,18) and bresults.branch(i,19)), but I'm not sure how to
>> put these two values together to represent the branch (as the thermal limits
>> are set for the branches and not each node).
>>
>> Is there another dual variable for the branch flow constraints that
>> represents the branch and not the to and from node?
>>
>>
>>
>> Thanks for any help on the subject.
>>
>> Sincerely,
>>
>> Mari Prydz
>> Norwegian University of Science and Technology
>>
>>
>>
>
>
>
>
> --
> Mvh
>
> Mari Hardersen Prydz,
> M.Sc. student, industrial economics and technology management,
> Norwegian University of Science and Technology,
> Tel: + 47 98077194 <>
>
