Question

Assuming there is a FAULT at BUS 3, Determine the thevenin equivalent of each series network as viewed from the fault bus.

Given:

-Prefault voltage is 1.0 per unit

-Prefault load currents and delta-wye transformer phase shifts are neglected

Synchronous generators G1 1000 MVA 15 kVX"-X2 0.18, Xo 0.07 per unit G2 1000 MVA 15 kV X: X, = 0.20, X,-0.10 per unit G3 500 MVA 13.8 kV X: X,-0.15, X,-0.05 per unit G4 750 MVA 13.8 kV X,-0.30, X,-0.40, X,-0.10 per unit Transformers TI 1000 MVA T2 1000 MVA T3500 MVA T4 750 MVA 15 kV Δ /765 kV Y X 15 kV Δ/765 kV Y X 15kV Y/765kV Y 15 kV Y/765 kV Y 0.10 per unit 0.10 per unit X = 0.12 per unit X = 0.11 per unit Transmission lines 1-2 765 kV 1-3 765 kV 2-3 765 kV The inductor connected to Generator 3 neutral has a reactance of 0.05 per unit using generator 3 ratings as a base. Draw the zero-, positive-, and negative-sequence reactance diagrams using a 1000-MVA, 765-kV base in the zone of line 1-2. Neglect the Δ Y transformer phase shifts. Line 1-3 3 2 Line 1-2 Line 2-3

Answer 1

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