A single-line diagram of a four-bus system is shown in Figure 7.20, for which \(\boldsymbol{Z}_{\text {bus }}\) is given below:

Let a three-phase fault occur at bus 2 of the network.

(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 unfaulted buses 1,3 , and 4 .

(d) Find the current flow in the line from bus 3 to bus 1. Assume the prefault voltage \(V_{f}\) at bus 2 to be \(1 \angle 0^{\circ}\) p.u., and neglect all prefault currents.

Transcribed Image Text:

Zbus = j [0.25 0.2 0.16 0.2 0.23 0.15 0.16 0.15 0.196 -0.14 0.151 0.1 0.14 0.151 0.1 0.195 per unit