A three-phase circuit question

[alternativess]

Homer, where are you? I need your guide to do this question, my midterm exam is coming...I get stucked in doing this exercise.

http://img446.imageshack.us/img446/1537/44444444448rh.png

[Homer]

For part a) you just need to draw the circuit using the information stated in the question.

For part b) you need to convert both the source and load from delta to wye impedances. Also convert the 13.8kV delta supply to a 13.8kv/1.73 wye supply. Once you have the wye equivalent you can draw the single phase (line-to-neutral) equivalent circuit.

Converting impedances is a bit of gruntwork where you need to switch back and forth between polar and rectangular representation.

Have a look at this (http://www.phy.mtu.edu/~suits/PH2230/DeltaY.pdf).

Homer