Solve in paper $....$A single line diagram of a $3-$phase power system is shown in Figure Q$2.$ Positive, negative and zero sequence impedances of the system are shown in Table Q$2.$

Table Q$2$

$\backslash$table$[[$Network Components,X$1($pu$),$X$2($pu$),$Xo $($pu$)],[$Generator $1(G_1),0\mathrm{.}2,0\mathrm{.}15,0\mathrm{.}05],[$Generator $),0\mathrm{.}3,0\mathrm{.}2,0\mathrm{.}05],[$Transformer $1(T_1),0\mathrm{.}2,0\mathrm{.}2,0\mathrm{.}2],[$Transformer $2(T_2),0\mathrm{.}15,0\mathrm{.}15,0\mathrm{.}15],[$Transmission line $1-2,0\mathrm{.}6,0\mathrm{.}6,1\mathrm{.}2]]$

The neutral of the generators $G_1$&$G_2$ are solidly grounded. The neutral of the Y winding of Transformer $T_1$ on the generator$-G_1$ side is grounded through a reactance of $x_N=jO\mathrm{.}01$ per unit. The neutral of the $Y$ winding of Transformer $T_2$ on the Bus$-2$ side is grounded through a resistance of $R_N=0\mathrm{.}02$ per unit. Transformers connections are shown in Figure Q$2($a$).($i$)$ Assume a single$-$line$-$to$-$ground fault $($phase a$)$ occurs at bus $2.$ The fault involves a reactance of $x_f=j0\mathrm{.}3$ per unit. Assume that the pre$-$fault generator voltages were $1\mathrm{.}0$ per unit.

Draw the positive sequence, $($PS$),$ network.

$[1$ marks$]$

Draw the negative sequence, $($NS$),$ network.

$[1$ marks$]$

Draw the zero sequence, $($ZS$),$ network.

$[1$ marks$]$

Draw the reduced PS Thevenin equivalent network "looking in$"$ at bus $2.$

$[2$ marks$]$

Draw the reduced NS Thevenin equivalent network "looking in$"$ at bus $2.$

$[2$ marks$]$

Draw the reduced ZS Thevenin equivalent network "looking in$"$ at bus $2.$

$[3$ marks$]$

Calculate the current symmetrical components $I_{A0},I_{A1},I_{A2}$ in per unit.

$[3$ marks$]$

Calculate the per unit phase currents $I_A,I_B,I_C.$

$[3$ marks$]$

Calculate the fault current, $I_F.$

$[1$ marks$]$

Calculate the voltage symmetrical components $V_{A0},V_{A1},V_{A2}$ in per unit.

$[5$ marks$]$

Calculate the per unit phase voltages $V_A,V_B,V_C.$

$[3$ marks$]$

$($ii$)$ If the Transformer $T_2$ Delta winding on the Generator $G_2$ side is $Y$ connected, with its neutral connected to ground, draw the zero sequence diagram.

$[1$ marks$]$