a) The one line diagram of a three phase system is shown below, draw an impedance diagram showing all impedances in per-unit on a 100 MVA base. b) The motor is drawing 40 MVA at 0.9 power factor lagging at a line- to-line terminal voltage of 10 KV. Determine the terminal voltage of the generator. X, = 48.40 50 MVA 100 MVA 11/220 KV 10% 220/11 KV 10% M 50 MVA 10 KV 18.15 % 80 MVA 11 VIT U 86 S = = 58.08 2

If the load draws a current of 2727 A, in phase, from a generator, which of the following statement is true? O A. The reactive power is flowing from generator to the load and the real power is flowing from the load to the generator. O B. Since the current is in phase with the generator voltage, both the real and reactive power is flowing from the generator to the load. O .Since the current is leading the generator, both the real and reactive power is flowing from the load to the generator. O D. The real power is flowing from generator to the load and the reactive power is flowing from the load to the generator. O E. None of the other choices are correct

In the system shown in Figure 1, the transformers are connected star-star with both star points grounded and the generator is connected in star with its star points grounded. The per unit impedances of each element on a 40 MVA base are given in Table 1 and the voltage levels are given in Table 2. Z [p.u.] 0 2 tööt Generator 0.01 +j0.08 p.u. L Figure 1: A section of the distribution system Transformer T1 Line V BASE [KV] 0.04 + j 0.03 + j 0.15000000000000002 0.06000000000000000 Generator Table 1: Sequence impedances (p.u. on 40 MVA base) 3 T2 181. Line 3 10 Table 2: Voltage bases (kV) Load 1 Transformer T2 Load Current A load current of 11.316 kA is flowing with a lagging power factor of 90 %. Convert this to a current vector in per-unit. IL = 0.04 + j 0.06000000000000000