A 220 kV transmission line is feeding a load as shown in Figure below, where: R1= 0 O/phase and X1 = 150 Q/phase. The sending-end voltage U is 220 kV. Bus 1 is chosen as the slack bus. While P2 = 100 MW, Q2 = 0 MVAr. Using Ubase = 220kV and Spase = {10*(Number formed by Last 2 digits of your roll number)} MVA:

The bus impedance matrix for a three-bus power system has per-unit elements as: Z11 = 0.5 Z12 = 0.4 Z13 = 0.8 Z21 = 1 Z22 = 0.5 Z23 = 0.6 Z31 = 0.5 Z32 = 1.2 Z33 = 1 Prefault voltage is 1 per unit and prefault current is neglected. A three-phase short circuit occurs at bus 3. Determine the subtransient fault current. Round your answer to 2 decimal places.

Q2: The constants of a 275 KV transmission line are A = 0.8525° and B = 200275° 0/phase. Draw the circle diagram to determine the power and power angle at unity power factor that can be received if the voltage profile at each end is to be maintained at 275 KV. What type a rating of compensating equipment will be required if the load is 150 MW at unity power factor with same voltage profile. (5.5 mark)