Example 8.4 The one line diagram of a simple three-bus power system is shown in the figure. Each generator is j0.1 j0.2 represented by an emf behind the transient reactance. All impedances are expressed in per unit j0.1 j0.2 in a common 100 MVA base, and for simplicity, j0.8 resistances are neglected. The following assumption 2 are made: j0.4 j0.4 •shunt capacitances are neglected and the system is considered on no load. •all generators are running at their rated voltage 3 and rated frequency with their emf in phase Determine the fault current, the bus voltages and the line currents during the fault when a balanced three-phase fault with a fault impedance Z; = j0.16 %3D p.u. fault occurs on bus 3

Example 8.4 The one line diagram of a simple three-bus power system is shown in the figure. Each generator is j0.1 j0.2 represented by an emf behind the transient reactance. All impedances are expressed in per unit j0.1 j0.2 in a common 100 MVA base, and for simplicity, j0.8 resistances are neglected. The following assumption 2 are made: j0.4 j0.4 •shunt capacitances are neglected and the system is considered on no load. •all generators are running at their rated voltage 3 and rated frequency with their emf in phase Determine the fault current, the bus voltages and the line currents during the fault when a balanced three-phase fault with a fault impedance Z; = j0.16 %3D p.u. fault occurs on bus 3

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

Chapter12: Power System Controls

Section: Chapter Questions

Problem 12.9P

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The one-line diagram of a simple power system is shown in Figure below. The neutral of each generator is grounded through a current-limiting reactor of 0.25/3 per unit on a 100-MVA base. The system data expressed in per unit on a common 100-MVA base is tabulated below. The generators are running on no-load at their rated voltage and rated frequency with their emfs in phase. G Stark Item Base MVA Voltage Rating X' x² 20 kV 20 kV 20/220 kV 20/220 kV 100 0.05 0.15 0.15 0.10 0.10 220 kV 0.125 0.125 0.30 0.15 0.25 025 0.7125 0.15 100 100 0.15 0.05 0.10 0.10 0.10 100 0.10 100 100 Lu La 220 kV 0.15 220 kV 0.35 100 A balanced three-phase fault at bus 3 through a fault impedance Zf= jo.I per unit. The magnitude of the fault current in amperes in phase b for this fault is: Select one: A. 345.3 B. 820.1 C. 312500 3888888 产产

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