For the three-phase power system with single-line diagram

Chapter , Problem 9.33

(choose chapter or problem)

For the three-phase power system with single-line diagram shown in Figure 9.22, equipment ratings and per-unit reactances are given as follows: Machines 1 and 2: 100 MVA 20 kV X1 _ X2 _ 0:2 X0 _ 0:04 Xn _ 0:04 Transformers 1 and 2: 100 MVA 20D=345Y kV X1 _ X2 _ X0 _ 0:08 Select a base of 100 MVA, 345 kV for the transmission line. On that base, the series reactances of the line are X1 _ X2 _ 0:15 and X0 _ 0:5 per unit. With a nominal system voltage of 345 kV at bus 3, machine 2 is operating as a motor drawing 50 MVA at 0.8 power factor lagging. Compute the change in voltage at bus 3 when the transmission line undergoes (a) a one-conductor-open fault, (b) a two-conductor-open fault along its span between buses 2 and 3.