(a) The bus impedance matrix for a three-bus power system is

where subtransient reactances were used to compute \(\boldsymbol{Z}_{\text {bus }}\). Prefault voltage is 1.0 per unit and prefault current is neglected.

(a) Draw the bus impedance matrix equivalent circuit (rake equivalent). Identify the perunit self- and mutual impedances as well as the prefault voltage in the circuit.

(b) A three-phase short circuit occurs at bus 2. Determine the subtransient fault current and the voltages at buses 1,2, and 3 during the fault.

(c) Repeat for the case of

0.12 0.08 0.04 Zbusj 0.08 0.12 0.06 0.04 0.06 0.08_ per unit