1) I am given a question in which a delta and Y transformation circuit are placed together in parallel. I know how to calculate the impedance but which set of equations do I use when calculating voltage?

Also is the voltage phase to phase or line to line?


Y-transform: V(line2line) = sqrt(3)V(phase) < 30degrees
Delta: V(line2line) = Vphase

When they are combined together in parallel, which equation should I use?

Also, what kind of current am I dealing with phase or line to line?

 

I think you need to post some pictures to clarify the problem...

 

change Y->delta or delta to Y and do the culculations? maybe makes it easier