Hi, In the matpower branch model (Fig 3.1) the impedance is on the TO-bus side. However, since the impedance is in pu, for an ideal transformer we might as well move the pu impedance to the FROM-bus right? So in this case we can exchange the TO-bus and FROM-bus for any branch without effecting the results of a load flow.
Q1. So when does the the ordering of the FROM and TO bus actually matter? Is there any case when we cannot swich the TO and FROM bus of a branch and still get the same result from a load flow or opf? Q2. From Figure 3.1 it looks as if the FROM bus is the high voltage bus (assuming N > 1). Is this always the case or can we have N < 1 just as well? Regards, Elis
