That is correct. For the power flow equations F(x) = 0, F, x and the Jacobian
J are all constructed with the desired ordering, so the ordering of the
original buses in the bus matrix does not matter.
Ray
On Jun 28, 2020, at 5:04 PM, Liang Chen
<[email protected]<mailto:[email protected]>> wrote:
Hello,
Regarding my previous question, I think I see where I'm wrong, but it would be
nice for someone to confirm:
The j1 ~ j6 indices are for the "reduced" J, i.e., the relevant PQ, PV entries
of the V, I or S vectors which are already sorted by the (pv, pq) or (pq) entry
indexing, which filter out the unwanted entries.
Liangjie
________________________________
From: Liang Chen
Sent: Friday, June 26, 2020 3:22 AM
To: MATPOWER discussion forum
<[email protected]<mailto:[email protected]>>
Subject: Bus type indexing in newtonpf.m
Hello,
I'm reading the source code (newtonpf.m) and noticed the following lines used
to indexing and updating the four "quadrants" of the J matrix according to
which variables are updated depending on whether it's a PV, PQ or Ref bus:
<Outlook-kgfa51hy.png>
My question is, doesn't this assume the ordering of PV-PQ-Ref buses in any V, I
or S vectors (that are N_BUS x 1 in size)? That is, say there are 9 buses,
where 1 is Ref, 4,6,7 are PV , and 2,3,5,8,9 are PQ, then the buses would be
ordered like so before this function was called:
4,6,7 2,3,5,8,9 1 (indices are sorted by bus type)
(PV) (PQ) (Ref)
And according to the source code it would've been
1,2,3 4,5,6,7,8, 9
(PV) (PQ) (Ref)
But I didn't notice where this assumption was checked to be valid...
I was thinking it should instead be:
Idx_PQ = [(internal/consecutive) indices of PQ buses, sorted]
Idx_PV = [... PV ...]
Idx_Ref = [... Ref ...] (of course there would only be 1 element)
and index as J11 = real(dSbus_dVa[all except Idx_Ref, all except Idx_Ref]), and
so on for J12, J21, and J22. But if the source code was truly incorrect in this
regard, surely it must have been pointed out before, so I'm thinking I made a
mistake somewhere.
Could you please point out where I'm wrong? Your time and help are much
appreciated.
Regards,
Liangjie Chen
