If the tap ratio is zero, then Matpower assumes that it is a non-transformer branch and sets it to 1.0 (so the branch admittance effectively stays the same).
Please read the manual to see the modeling of transformers as done in Matpower. Shri Always, always, always send your querries to the MATPOWER mailing list. From: ?π??????? ??????π????? <arsenop...@gmail.com<mailto:arsenop...@gmail.com>> Date: Monday, April 6, 2015 at 11:44 AM To: Shri <abhy...@mcs.anl.gov<mailto:abhy...@mcs.anl.gov>> Subject: Re: URGENT Hello Shri, Sorry for late response but i am busy working on a project. Firts of all thank's for your help.You are amazing. Furhtermore, i want to ask you one more question: I want to model a transformer but i don't know how. In my way, i modelled it as a reactance with a tap ratio equal to 1. But if i change the tap ratio and set it to 0 the results won't change. I have at my disposal a transformer 0.66/20 kV that operates with the nominal transformation ratio. Could you please help me? Thank you in advance, AA 2015-04-01 22:20 GMT+03:00 Abhyankar, Shrirang G. <abhy...@mcs.anl.gov<mailto:abhy...@mcs.anl.gov>>: Its not clear what you mean by "different" outcomes. Is the difference small, large, converged/diverged, related to real/reactive power, bus voltage magnitudes/angles. I am not familar with NEPLAN. But, here are some things you should check: i) Are you running the same application (AC Power Flow) in both NEPLAN and MATPOWER :-) ii) Are you correctly specifying the network according to the data format for NEPLAN? iii) Is the application running the same algorithm (Newton Method or decoupled load flow or other) iv) Are you using the same tolerances, number of iterations as in MATPOWER? v) Are generator reactive power limits active? Are shunt switching caps active? Is transformer tap switching active? MATPOWER does not do any of these active by default. In fact, there is no support (yet) for shunt capacitor and transformer switching. vi) Is the swing bus angle same as MATPOWER. Note that some packages such as PSSe use 0 degrees for swing bus angle. MATPOWER does not have that restriction. You can choose any swing bus angle that you want. vii) Is the modeling done differently in NEPLAN for transmission lines, transformers, photovoltaic generators? viii) Does MATPOWER show 'Converged in xxx iterations' when displaying the results. I may have missed some others, but if (i)-(vii) are same then you should get the same solution unless NEPLAN is doing something funky. Shri ________________________________ From: ?π??????? ??????π????? [arsenop...@gmail.com<mailto:arsenop...@gmail.com>] Sent: Wednesday, April 01, 2015 7:07 AM To: Abhyankar, Shrirang G. Subject: URGENT Hello Shri, Sorry for interrupting you but i have to ask you something relative to matpower. I know i should send an email to the matpower list but it is kind of an urgent so please do not disregard it. I have to model a photovoltaic generator(inductive). So i put his P,Q in the generator matrix and i set his bus as PQ. However i have at my disposal some results coming from the same network in NEPLAN that show different outcomes than mine ones in MATPOWER.Do you have any ideas of what is going on??? I am running out of time so please help. Thank you in advance, Apostolos -- Arsenopoulos V. Apostolos Power Systems Laboratory Electrical and Computer Engineering Department, Democritus University of Thrace Xanthi, Greece E-mail: aposa...@ee.duth.gr<mailto:arsen...@vet.auth.gr>
