Thanks very much! ________________________________ From: bounce-125782784-86837...@list.cornell.edu <bounce-125782784-86837...@list.cornell.edu> on behalf of Ray Daniel Zimmerman <r...@cornell.edu> Sent: Tuesday, July 20, 2021 6:39 AM To: MATPOWER-L <matpowe...@list.cornell.edu> Subject: Re: Ybus Construction: Parallel Branch Modelling for Power Flow
EXTERNAL EMAIL: It is perfectly fine to replace parallel branches with a single equivalent branch. If done properly, it will result in an identical power flow solution. Ray On Jul 16, 2021, at 1:22 PM, Liang Chen <liangjie.c...@mail.utoronto.ca<mailto:liangjie.c...@mail.utoronto.ca>> wrote: Dear all, I have a question regarding the construction of the admittance matrix (Equations 3.11-3.13 in the documentation, Modelling > Network Equations). I noticed that there are cases in which there are more than one branch from bus i to bus j, and cases where there are branches (i,j) and (j,i), i.e., both from i to j, and from j to i. For example, in case13659pegase.m, the branches (11001, 9689) and (9689, 11001) both exist and have different impedance values. My question is that, if we model the system as a simple directed graph for the power flow analysis (so the branch flow limits aren't important, and technically there cannot be multiple edges between any two nodes), could there be an issue if I "merge" the multiple parallel branches into a single equivalent branch? In addition, in the case where both branches (i,j) and (j,i) exist, if they both have unity transformer turns ratio, could there be a problem if I flip (j,i) to be (i,j) and proceed to merge the two into one single equivalent branch? Thank you for your time and help! Liangjie
