Determine \(\boldsymbol{Y}_{\text {bus }}\) in per unit for the circuit in Problem 7.14. Then invert \(\boldsymbol{Y}_{\text {bus }}\) to obtain \(\boldsymbol{Z}_{\text {bus }}\).

Problem 7.14

Equipment ratings for the five-bus power system shown in Figure 7.15 are as follows:

A three-phase short circuit occurs at bus 5, where the prefault voltage is 15kV.

Generator Gl: Generator G2: Transformer Tl: Transformer T2: Each 138-kV line: 50 MVA, 12 kV, X" = 0.2 per unit 100 MVA, 15 kV, X"= 0.2 per unit 50 MVA, 10 kV Y/138 kV Y, X = 0.10 per unit 100 MVA, 15 kV A/138 kV Y, X = 0.10 per unit X = 40 2.