7.12 Equipment ratings for the four-bus power system shown in Figure 7.14 are as follows: Generator G1 : Generator G2: Generator G3: Transformer T1: Transformer T2: Transformer T3: Each 500-kV line: 500 MVA, 13.8 kV, X" = 0.20 per unit 750 MVA, 18 kV, X" 0.18 per unit I(NM) MVA, ) kV, X" 0.IY pkr unit 500 MVA, 13.8 /500 Y kV, X-0.12 per unit 750 MVA, 18 /500 Y kV, X = 0.10 per unit 1000 MVA, 20 A/500 Y kV, X = 0.10 per unit X = 50 A three-phase short circuit occurs at bus 1, where the prefault voltage is 525 kV. Prefault load current is neglected. Draw the positive-sequence reactance diagram in FIGURE 7.14 G1 /50 /50 Problems 7.12, 7.13, 7.19, 7.24, 7.25, 7.26 /50 4 T2 G2