(Solved):   Q2 A three-phase unbalanced star-connected load is connected to a balanced three-phase pow ...

 

Q2 A three-phase unbalanced star-connected load is connected to a balanced three-phase power source of 346 V, 50 Hz in positive sequence L1-L2-L3 as shown in figure Q2. It is known that the line currents Ili, lu2 and lu3 are 1.82-60 A, 2.4 2-50 A and 3.3 Z40 A respectively. By taking VLI-N as reference, calculate LT ILI N IN N Z2 23 Z TL2 L3 IL2 123 figure Q2 (a) the load impedance Z1, Z2 and Zz in rectangular form; (4 marks) (b) the total real power of the whole system; (4 marks) (c) the total reactive power of the whole system; (4 marks) (d) the neutral current IN; (2 marks) (e) the overall apparent power of the whole system; and (2 marks) (f) the overall power factor. (4 marks) (g) Can two-wattmeter method be used to measure the total power consumption of the whole system shown in figure Q2? Give reason to support your answer. (5 marks) End of questions