I remember I did check extensively the conversion of two-winding transformers a few years back; however, I did not check 3-winding ones.
You can check those formulas in this article by Siemens: "Modeling of Three-Winding Voltage Regulating Transformers for Positive Sequence Load Flow Analysis in PSS/E" https://w3.usa.siemens.com/datapool/us/SmartGrid/docs/pti/2010July/PDFS/Modeling%20of%20Three%20Winding%20Voltage%20Regulating%20Transformers.pdf -- Jose L. Marin Grupo AIA 2018-08-31 0:12 GMT+02:00 Ray Zimmerman <[email protected]>: > This code was contributed by Yujia Zhu when he was at ASU working with Dan > Tylavsky. I’m afraid I’m not familiar with the details of that code, but > I’m pretty sure it was double-checked extensively against PSS/E’s internal > models. > > Ray > > > On Aug 6, 2018, at 4:50 AM, Aebi Stefanie <[email protected]> > wrote: > > Dear all > > > I am trying to convert a PSSE .raw network case to mpc format. > > > I just discovered that I obtain negative branch parameters for some of the > 3-winding transformers in my System, i.e. x < 0, r < 0. I tried to track > the phenomenon and found the following section in psse_convert_xfmr.m: > > > R1 = (R12+R31-R23) ./ 2; > R2 = (R12+R23-R31) ./ 2; > R3 = (R31+R23-R12) ./ 2; > X1 = (X12+X31-X23) ./ 2; > X2 = (X12+X23-X31) ./ 2; > X3 = (X31+X23-X12) ./ 2; > > > I've got a number of branches where the negative term (e.g. R23 in > calculation of R1) is the biggest one, such that the resulting R or X is > negative. > > > Where does this definition come from? > And is there a way I can avoid getting negative line parameters? > > > Thanks for your help. > > > Kind regards, > Stefanie Aebi > > >
