Consider a power system network with two motor loads of 20 MW and 15 MW both fed at 30 kV with lagging power factors of 0.88 and 0.85 respectively. The power system is supplied by two parallel connected generators (one rated 20 MVA and the other 25 MVA both rated 11kV), via a 11/220kV substation, a 220kV transmission line, 220/33 kV substation and 33 kV feeder. Each substation has a 100 MVA transformer with an impedance of 19% referred to the secondary side. The transmission line impedance is (3.5 + j8.4) Ω while the feeder impedance is (2.15 + j0.9) Ω.
i) Draw a one-line and impedance diagrams representing the above power system network on a per unit basis. (The system frequency is 50 Hz).
ii) Calculate the generator bus terminal voltage.