A balanced, three-phase, Y-connected source has a line voltage of 440 Vrms. The source frequency is 60 Hz. The balanced, three-phase loads have the following characteristics:
Zy1: P1 = 15 kW and Q1 = +18 kVAR
Z?2: |S2|=21 kVA and PF2 = 0.500 lagging
Z?3: PF3 = 0.2 lagging and Ip3 = 25 A rms
Zy4: 1.67?60º O
(note, power values are all three-phase quantities)
1. Determine each impedance and the current for each load.
2. Determine the total line current, IaA.
3. Determine the total complex power, average power, and reactive power delivered by the source to the loads.
4. What is the power factor of the four loads combined?
5. It is necessary to add a parallel load in the configuration to the circuit to minimize the magnitude of the line current. The line voltage and total average power delivered by the source may not change. What are the impedance and the component value of this load?
6. What is the power factor of the additional load?
7. What is the power factor of the five loads combined?