Question

Problem 1 (25 Points)The single-line diagram of a three-phase power system is shown in Figure 1. Equipment ratings are given as follows: The inductor connected to Generator 3 neutral has

a reactance of 0.05 pu using generator 3 ratings as abase. Neglect the A-Y transformer phase shifts and per-fault load currents. a) Draw the positive,negative, zero sequence reactance diagrams using a 1000-MVA, 765-kV base in the zone of line 1-2. b)Fault at bus 1 are of interest. Determine the Thevenin equivalents of positive, negative, zero sequence networks as viewed from the faulted bus. Prefault voltage is 1.0 pu. e) Determine the subtransient fault current in pu and in kA during a bolted three-phase symmetrical fault at bus 1.

Fig: 1

Fig: 2

Fig: 3

Fig: 4

Fig: 5