The one-line diagram of a power system is shown in the figure below. A single-line-to-ground (SLG) fault occurs at bus 2. Assume the fault impedance Z,= j0.08 pu. Calculatethe fault current (in per unit).T,2MLineX, = X2 = 40 NXo =1200%3D100 MVA13.8 kV100 MVA100 MVAX, = 0.15 13.8-kVA/138-kVYX = 0.10 per unit138-kV Y/13.8-kV A100 MVAX2 = 0.17X = 0.10 per unit13.8 kVX, = 0.20X2 = 0.21Xo = 0.10X, = 0.05 per unitXo = 0.05 per unit

A single line to ground fault occurs at bus 2. So the fault current will be- Ea=Genetaror terminal…

The one-line diagram of a power system is shown in the figure below. A single-line-to- ground (SLG) fault occurs at bus 2. Assume the fault impedance Zj=j0.08 pu. Calculate the fault current (in per unit). 2 M Line X, = X2 = 40 N 1 Xo = 1200 100 MVA 13.8 kV 100 MVA 100 MVA X, = 0.15 X2 = 0.17 X, = 0.05 per unit 138-kV Y/13.8-kV A X = 0.10 per unit 13.8-kVA/138-kVY 100 MVA X = 0.10 per unit 13.8 kV X, = 0.20 X2 = 0.21 0 10

The one-line diagram of a power system is shown in the figure below. A single-line-to- ground (SLG) fault occurs at bus 2. Assume the fault impedance Zj=j0.08 pu. Calculate the fault current (in per unit). 2 M Line X, = X2 = 40 N 1 Xo = 1200 100 MVA 13.8 kV 100 MVA 100 MVA X, = 0.15 X2 = 0.17 X, = 0.05 per unit 138-kV Y/13.8-kV A X = 0.10 per unit 13.8-kVA/138-kVY 100 MVA X = 0.10 per unit 13.8 kV X, = 0.20 X2 = 0.21 0 10

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

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

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

Chapter9: Unsymmetrical Faults

Section: Chapter Questions

Problem 9.36P

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A three-phase circuit breaker has a 15.5-kV rated maximum voltage, 9.0-kA rated short-circuit current, and a 2.50-rated voltage range factor. (a) Determine the symmetrical interrupting capability at 10-kV and 5-kV operating voltages. (b) Can this breaker be safely installed at a three-phase bus where the symmetrical fault current is 10 kA, the operating voltage is 13.8 k V, and the (X/R) ratio is 12?
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