1. Transformer Per-Unit AnalysisA power system consists of a generator rated at 500 MVA, 20 kV, and a transformer rated at500 MVA, 20/230 kV with an impedance of 0.01 + j0.05 per unit on its own base. Thetransformer is connected to a transmission line with an impedance of 0.02 + j0.1 per unit ona 230 kV, 500 MVA base.a. Convert the transformer impedance to the generator base.b. Calculate the per-unit impedance of the transmission line on the generator base.c. Determine the total impedance of the system (generator, transformer, and transmissionline) in per-unit on the generator base.

5. Transformer ConnectionA power system includes two transformers: T1 (100 MVA, 110/11 kV, impedance 0.05 pu)and T2 (100 MVA, 11/0.4 kV, impedance 0.06 pu). They are connected in series, with T1stepping down from 110 kV to 11 kV and T2 stepping down from 11 kV to 0.4 kV.a. Determine the per-unit impedance of each transformer on a common base of 100 MVA, 11kV.b. Find the equivalent per-unit impedance of the combined transformer system.c. Calculate the actual impedance in ohms on the 0.4 kV side

Given the normalised load impedance is zL  = 0.4+1.4j on a 50 Ω transmission line system (you may use Smith chart to answer the question):Select one:a.The load reflection coefficient is |ΓL| = 0.8 and theta =68 degb.The VSWR changes as we move along the line toward the generatorc.The voltage standing wave ratio is VSWR=2d.The voltage standing wave ratio is VSWR=5e.The load reflection coefficient is |ΓL| = 0.6745 and theta =26.5 deg

A three-phase fault occurs at the end of a transmission line connected to a bus. The systemconsists of a generator (1000 MVA, 22 kV) with a sub-transient reactance of 0.2 per unit,and a step-up transformer (1000 MVA, 22/220 kV) with a per-unit impedance of 0.1 perunit on its own base. The transmission line has an impedance of 0.1 + j0.5 per unit on a 220kV, 1000 MVA base.a. Convert all impedances to a common base of 1000 MVA, 22 kV.

6. Multi-Voltage Level SystemA power system includes a generator (500 MVA, 13.8 kV, X'' = 0.2 pu), a transformer (500MVA, 13.8/138 kV, Z = 0.1 pu), and a transmission line (Z = 0.02 + j0.1 pu on 138 kV, 500MVA base). A load of 450 MW at 0.9 power factor lagging is connected at the end of thetransmission line.a. Convert all impedances to a common base of 500 MVA, 13.8 kV.b. Calculate the per-unit voltage at the load bus.

Question 2List three functions which a transformer may perform in an electrical circuit. [3 marks]A 10kVA, 50 Hz distribution transformer has 600 turns in the primary and 120 turns in thesecondary. The primary and secondary resistances are r1 = 0.2 Ω and r 2 = 0.02 Ω respectively,and the corresponding leakage reactances are Xl1 = 1.0 Ω, and Xl2 = 0.04 Ω respectively. Thesupply voltage is 1100V.Calculate(a) The equivalent impedance, resistance and reactance, referring all quantities to thehigh voltage (primary) side; [6 marks](b) The secondary terminal voltage for full load having a power factor of 0.7 lagging;Draw the phasor diagram; [7 marks](c) The regulation in (b) [4 marks]2130310310