5. The positive sequence network, negative sequence network and zero sequence network are shown in Figure 3, consider a single-line-to-ground fault at point f(faulted phase is phase A, fault impedance is 0.05, (1)Draw the interconnected sequence network; (2)determine the sequence current and phase current.

5. The positive sequence network, negative sequence network and zero sequence network are shown in Figure 3, consider a single-line-to-ground fault at point f(faulted phase is phase A, fault impedance is 0.05, (1)Draw the interconnected sequence network; (2)determine the sequence current and phase current.

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 9.7MCQ

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Similar questions

At the general three-phase bus shown in Figure 9.7(a) of the text, consider a simultaneous single line-to-ground fault on phase a and line-to-line fault between phases b and c, with no fault impedances. Obtain the sequence-network interconnection satisfying the current and voltage constraints.
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?
Equipment ratings for the five-bus power system shown in Figure 7.15 are as follows: Generator G1:Â Â Â Â 50Â MVA,Â 12kV,Â X=0.2 per unit Generator G2: 100Â MVA, 15 kV, X=0.2 per unit Transformer T1: 50 MVA, 10 kV Y/138kVY,X=0.10 per unit Transformer T2: 100 MVA, 15 kV /138kVY,X=0.10 per unit Each 138-kV line: X1=40 A three-phase short circuit occurs at bus 5, where the prefault voltage is 15 kV. Prefault load current is neglected. (a) Draw the positive-sequence reactance diagram in unit on a 100-MVA, 15-kV base in the zone of generator G2. Determine (b) the ThĂ©venin equivalent at the fault, (c) the subtransient fault current in per unit and in kA rms, and (d) contributions to the fault from generator G2 and from transformer T2.
Equipment ratings for the four-bus power system shown in Figure 7.14 are as follows: Generator G1: 500 MVA, 13.8 kV, X=0.20 per unit Generator G2: 750 MVA, 18 kV, X=0.18 per unit Generator G3: 1000 MVA, 20 kV, X=0.17 per unit Transformer T1: 500 MVA, 13.8/500YkV,X=0.12 per unit Transformer T2: 750 MVA, 18/500YkV,X=0.10 per unit Transformer T3: 1000Â MVA, 20/500YkV,X=0.10 per unit A three-phase short circuit occurs at bus 1, where the prefault voltage is 525 kV. Prefault load current is neglected. Draw the positive-sequence reactance diagram in per unit on a 1000-MVA, 20-kV base in the zone of generator G3. Determine (a) the ThĂ©venin reactance in per unit at the fault, (b) the subtransient fault current in per unit and in kA rms, and (c) contributions to the fault current from generator G1 and from line 1-2.
Thévenin equivalent sequence networks looking into the faulted bus of a power system are given with ?1=?0.15 , ?2=?0.15 , ?0=?0.2and ?1=1∠0°per unit. Compute the fault currents and voltages for the followingfaults occurring at the faulted bus: (a) Balanced three-phase fault (b) Single line-to-ground fault (c) Line-line fault (d) Double line-to-ground fault Which is the worst fault from the viewpoint of the fault current?
Given the 4 bus network shown below, assume that there are no loads and all buses are at the rated voltage and all have the same phase angles. Assume that shunt capacitances are neglected. The relevant transient reactances for the generators and the reactances for the transformers are shown. Solve for the fault current through the fault impedance for a fault at bus 4 with a fault impedance of j0.1 pu. HINT: Use Delta to Wye conversion.