CAN209 ADVANCED ELECTRICAL CIRCUIT AND MAGNETICS

Three Phase Circuits

1. A balanced three-phase system is shown below.

(a) Determine the connection type of the system.

(b) Find the line current and the average power delivered to the load.

2. Considering a balanced Delta-Delta circuit, a delta-connected source supplies power to a delta-connected load through wires having impedances of Zline. The impedances of each wire and of each load ZΔ  are given to be

zline  = 0.3 + j0.4 Ω,  ZΔ=30+j6 Ω

The source voltages are

Vab  = 1000∠30° Vbc  = 1000∠− 90°V  Vca = 1000∠150° V 

Determine the following:

(a)       The line current IaA

(b)       The line-to-line voltage VAB  at the load

(c)       The current IAB  in phase A of the load

(d)       The total real power delivered to the load

(e)       The total power dissipated in the line

3. Determine the amplitude of the line current in a three-phase system with a 300 Vrms line voltage that supplies 1200 W to a Y-connected load at a lagging PF of 0.8.