$10\mathrm{.}19.$ The positive$-$sequence reactances for the power system shown in Figure $88$ are in per unit on a common MVA base. Resistances are neglected and the negative$-$sequence impedances are assumed to be the same as the positive$-$sequence impedances. A bolted line$-$to$-$line fault occurs between phases $b$ and $c$ at bus $2.$ Before the fault occurrence, all bus voltages are $1\mathrm{.}0$ per unit. Obtain the positivesequence bus impedance matrix. Find the fault current, the three$-$phase bus voltages during fault, and the line currents in each phase. Check your results using the zbuild and llfault programs.

FIGURE $88$

Circuit for Problem $10\mathrm{.}19.$

The following command

$($Find the kind of fault L$-$G$)$