A typical power system network with two generators G₁ and G2 supplies power to an aggregate motor load (M) is shown in Figure Q3. Rating of equipment and their respective sequence reactance are indicated in the diagram. Use G₁ rating as a base. a) For a fault on bus 4, analyze the network configuration for the Thevenin's equivalent positive, negative, and zero sequence impedances. b) Assess the fault current and fault level when a single line-to-ground fault occurred in the transmission line at bus 4. 60 MVA 3 Overhead line, L₁ X₁ X₂ = X₁ = 0.10 pu on 60 MVA 4 13.8 kV X₁ = 0.08 G₁ T₁ 2 X₂ = 0.08 Xo = 0.05 MY 50 MVA 13.8 kV X₁ = 0.06 ΔΥ Overhead line, L2 X = Xz = Xo = 0.10 pu on 60 MVA X₂ = 0.06 125 MVA 13.8/120 kV X = 0.12 Xo = 0.04 G₂ Figure Q3 T₂ 38 YA 125 MVA 120/13.8 kV X = 0.12 75 MVA 13.8 kV X₁ = 0.10 X₂ = 0.10 Xo = 0.06

A typical power system network with two generators G₁ and G2 supplies power to an aggregate motor load (M) is shown in Figure Q3. Rating of equipment and their respective sequence reactance are indicated in the diagram. Use G₁ rating as a base. a) For a fault on bus 4, analyze the network configuration for the Thevenin's equivalent positive, negative, and zero sequence impedances. b) Assess the fault current and fault level when a single line-to-ground fault occurred in the transmission line at bus 4. 60 MVA 3 Overhead line, L₁ X₁ X₂ = X₁ = 0.10 pu on 60 MVA 4 13.8 kV X₁ = 0.08 G₁ T₁ 2 X₂ = 0.08 Xo = 0.05 MY 50 MVA 13.8 kV X₁ = 0.06 ΔΥ Overhead line, L2 X = Xz = Xo = 0.10 pu on 60 MVA X₂ = 0.06 125 MVA 13.8/120 kV X = 0.12 Xo = 0.04 G₂ Figure Q3 T₂ 38 YA 125 MVA 120/13.8 kV X = 0.12 75 MVA 13.8 kV X₁ = 0.10 X₂ = 0.10 Xo = 0.06

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 9.35P

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