b) A fault occurs at bus 2 of the network shown in Figure Q3. Pre-fault nodal voltages throughout the network are of 1 p.u. and the impedance of the electric arc is neglected. Sequence impedance parameters of the generator, transmission lines, and transformer are given in Figure Q3, where X and Y are the last two digits of your student number. JX20)- /0.1X p.u. jX2 0.1X p.u. Xao)- J0.2Y p.u. %3D %3D V= 120° p.u. V 120° p.u. V, 120° p.u. jXa) /0.2X p.u. iXa2 j0.2X p.u. jX40) 0.2Y p.u. !! jXn)= 10.25 p.u. i A 2 Xng 0.25 p.u. 3 jXno)- j0.3 p.u. 0 X-70.2Y p.u. XT2- /0.2Y p.u. jXT1=70.2Y p.u. jXp)" J0.1X p.u. Xp- 0.1X p.u. Xo - /0.05 p.u. 0- %D !! 0. Figure Q3. Circuit for problem 3b). For example, if your student number is c1700123, then: jXa1) = j0.22 p.u., jXa(2) j0.22 p.u., and jXaco) = j0.23 p. u. %3D %3D (i) Assuming a balanced excitation, draw the positive, negative and zero (1) sequence Thévenin equivalent circuits as seen from bus 2. (i1) Determine the positive sequence fault current for the case when a three- phase-to-ground fault occurs at bus 2 of the network. (iii) Determine the short-circuit fault current for the case when a one-phase- to-ground fault occurs at bus 2.