From the diagram of Figure 7.46, it can be verified that each impedance sees the
corresponding phase voltage across itself; thus, since the currents ˜Ia, ˜Ib, and ˜Ic
have the same rms value, ˜ I , the phase angles of the currents will differ by ±120◦.
It is therefore possible to compute the power for each phase by considering the
phase voltage (equal to the load voltage) for each impedance, and the associated
line current. Let us denote the complex power for each phase by S: