Repeat Problems 9.1 and 9.14 including (Delta-Y) transformer phase shifts. Assume American standard phase shift. Also calculate

Question:

Repeat Problems 9.1 and 9.14 including \(\Delta-Y\) transformer phase shifts. Assume American standard phase shift. Also calculate the sequence components and phase components of the contribution to the fault current from generator \(n\) ( \(n=1,2\), or 3 as specified by the instructor in Problem 9.2).

Problem 9.1

The single-line diagram of a three-phase power system is shown in Figure 9.17. Equipment ratings are given as follows:

Synchronous generators:

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Transformers:

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Transmission lines:

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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 \(1000-\mathrm{MVA}, 765-\mathrm{kV}\) base in the zone of line 1-2. Neglect the \(\Delta-Y\) transformer phase shifts.

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Problem 9.14

Determine the subtransient fault current in per-unit and in kA, as well as the per-unit line-to-ground voltages at the fault bus for a bolted single line-to-ground fault at the fault bus selected in Problem 9.2.

Problem 9.2

Faults at bus \(n\) in Problem 9.1 are of interest (the instructor selects \(n=1\), 2, or 3). Determine the Thévenin equivalent of each sequence network as viewed from the fault bus. Prefault voltage is 1.0 per unit. Prefault load currents and \(\Delta-Y\) transformer phase shifts are neglected. 

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Related Book For  book-img-for-question

Power System Analysis And Design

ISBN: 9781305632134

6th Edition

Authors: J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

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