Maybe this can explain why a number of branches in case145 have negative series resistance and impedance. I was wondering why this was the case.
Regards, Elis Den mån 3 sep. 2018 kl 08:29 skrev Jose Luis Marín <[email protected]>: > > 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 >> >> >> >
