3-Phase Circuit - Line Current Calculation Question

[joenooch]

Hello,

While reviewing my professor's notes and my textbook I've run to a discrepancy in regard to how to calculate line current in a 3-phase circuit.

In these particular examples, you are given a 3-phase balanced y-source connected to a y-load with equal impedance on each phase. In addition, there is an equal line impedance on each phase.

The question ask to calculate the line current.

In several of my examples, the line current is calculated using the impedance of the y-load and NEGLECTS the line impedance.

In several other examples, the line current is calculated using both the impedance of the y-load and INCLUDES the line impedance in the calculation.

Which is the correct method?

Thanks!

 

[ajith.mk91]

In this case both line current and phase current are the same. So add both line impedance and Y-load(single branch) and divide the phase voltage with the result to get line/phase current.