I should also mention that the pull request Shri referenced with respect to
transformer taps is for power flow, not OPF.
Ray
> On Sep 26, 2017, at 11:49 AM, Elis Nycander <[email protected]> wrote:
>
> Hey, thanks for your answers.
>
> Indeed the solution is the same if the tap ratios are set to 0 or 1 (as long
> as the SHIFTS are all 0), it was just an error on my part.
>
> Ah, no callback for OPF? I just assumed that there was something similar to
> the callback functions in the CPF. Thanks for the links.
>
> Regards,
> Elis
>
>
>
> 2017-09-25 18:34 GMT+02:00 Abhyankar, Shrirang G. <[email protected]
> <mailto:[email protected]>>:
>
>
> Dear Matpower users,
>
> I have some questions about tap ratios in Matpwer.
>
> What does it mean if the tap ratios TAP are set to 0?
>
> Tap ratio=0 is used to indicate that the branch is a non-transformer branch,
> while 1 indicates a transformer branch. Even if you set the tap ratio = 0 for
> a transformer, MATPOWER internally uses a unity tap ratio meaning a 1:1
> voltage transformation.
>
> I have previously run some power flows without caring about the tap ratios
> (TAP = 0). Now I set them to 1, and got quite different results.
>
> I don’t think this should happen. With 0 or 1, the power flow results should
> be same.
>
> I can't see that the admittance matrix in Figure 3.1 in the manual is well
> defined for zero tap ratio, so I thought setting them to 0 was like
> deactivating them.
>
> Also, if I want to run an OPF with active tap changers, would it be best to
> include the tap ratios directly in the optimization constraints or to change
> the tap ratios in a callback function? Or maybe I can run several OPFs and
> change the tap ratios manually between each?
>
>
> Incorporating tap changers in OPF is a non-trivial task. Moreover, I don’t
> think there is a callback function in PF or OPF.
>
> Here are some relevant discussions from the mailing list.
>
> https://www.mail-archive.com/[email protected]/msg04162.html
> <https://www.mail-archive.com/[email protected]/msg04162.html>
> https://www.mail-archive.com/[email protected]/msg03339.html
> <https://www.mail-archive.com/[email protected]/msg03339.html>
> Note that there is a pending pull request for this feature. You can try that
> out if you like.
>
> Shri
>
>
> Regards,
> Elis Nycander
>
>
