3. Refer to the three-phase Y-connected ac circuit shown in Figure 3 with the parameters Vpcc = 480 V (line-to-line, rms
Posted: Thu Jun 02, 2022 9:30 am
3. Refer to the three-phase Y-connected ac circuit shown in Figure 3 with the parameters Vpcc = 480 V (line-to-line, rms value). f = 50 Hz, Z; = (1 + j2) n (per phase). The impedance Z, includes the Thevenin equivalent impedance and the line impedance. The loads' parameters are: Load 1: Y-connected and balanced, the per-phase impedance is Z₁y = (100 + j20) n Load 2: A-connected and balanced, the delta per-phase impedance is Z₂4 = (180 + j120) n. Load 3: S3 = 9 KVA, the power factor is 0.6 (lagging). Vycz Load 1 Z₂ Load 2 Load 3 Izs Figure 3 (a) Calculate the currents 111-112 113 and Is (Y-currents). [8 marks] (b) Calculate active and reactive power absorbed by Load 1 and Load 2 (the sum of the three phases). [6 marks] (c) Calculate the voltage source V₂. [3 marks] (d) Calculate the active and reactive powers provided by the source (the sum of the three phases). [4 marks] (e) Calculate the total impedance seen by the source. [4 marks] (TOTAL 25 MARKS)