Is there a reason that a single OPF with the combined system, including the tie
line, doesn’t do what you want? That should minimize cost of operation of the
entire system, taking into account the effect of losses in all lines, including
the tie line.
Ray
> On Mar 26, 2015, at 4:29 AM, 李岩松 <[email protected]> wrote:
>
> It’s an AC model and I want to tie two independent grids together, which
> are a bit far from each other. As the tie line is much longer than the lines
> inside each grid, I should take the power or loss on the tie line into
> account so as to avoid the case that the power flow on the tie line is only
> 0.01 p.u. which maybe uneconomic.
>
> If it’s not attainable by using OPF, I'm wonding if I can use GA or PSO
> for optimizing by calling PF of matpower in the process to add Ptie-loss in
> the object.
>
> Appreciate your help and thanks so much.
>
> Yansong Li
>
> 2015/3/26
>
>
>
>
>
>
> At 2015-03-23 23:52:40, "Ray Zimmerman" <[email protected]> wrote:
> The power flow in branch 3 is not an optimization variable, so you need to
> express your cost as a function of the optimization variables. For an AC
> power flow model, this is non-linear, so that’s problematic. For a DC power
> flow model, however, the flow is a linear function of the angles so you can
> apply a user-defined cost to it. I suggest you take a look at
> toggle_softlims.m for an example of code that puts a cost on the flow that
> exceeds a threshold. What you want to do is nearly identical (for the DC
> case), except that your threshold would be zero and you are only doing it for
> a specific line.
>
> Ray
>
>
>> On Mar 20, 2015, at 8:59 AM, 李岩松 <[email protected]
>> <mailto:[email protected]>> wrote:
>>
>> Dear All:
>>
>> I have studied the ‘6.3 Extended OPF Formulation’ and '7 Extending the
>> OPF’ in ‘manual.pdf’ to include additional cost in the function but failed
>> to figure it out.
>>
>> The default objective function is the total cost of all the generators per
>> hour.
>>
>>
>> Now I want to add ‘Pbranch3*ξ’, in which Pbranch3 is the active power
>> transferred on branch 3 and ξ is the electricity price which is a constant.
>>
>> <截图1.png>
>>
>>
>> With greatest pleasure to get any response.
>> Yours sincerely
>> Yansong Li
>> 2015/03/20
>>
>>
>
>
>
