A single-line diagram of a 4-bus system is shown in Figure 1. Let a three-phase fault occur at bus 2 of the network. Apply Zbus method to: (a) Calculate the

initial symmetrical RMS current in the fault. (b)Determine the voltages during the fault at buses 1, 3, and 4. (c) Compute the fault currents contributed to bus 2 by the adjacent un-faulted buses 1, 3, and 4. (d) Find the current flow in the line from bus 3 to bus 1. Assume the pre-fault voltage Vr at bus 2 to be 120° pu. Neglect all pre-fault currents.