A generator supplies a motor through a Y-A transformer. The generator is connected to Y side ofthe transformer. A fault occurs between the motor terminals and the transformer. Thesymmetrical components of the subtransient current in the motor flowing toward the fault are:I =-0.8- j2.6puI =-j2.0puI =-j3puFrom the transformer toward the Fault:I = 0.8– j0.4puI? =-j1.0pu1 = OpuAssume X =X,=X, for both the motor and the generator.(a) Describe the fault type and find the prefault current, if any, in line a.(b) Determine the subtransient fault current in per unit.(c) Calculate the subtransient current in each phase of the generator in per unit taking intoconsideration the phase shift of the Y-A transformer.

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A generator supplies a motor through a Y-A transformer. The generator is connected to Y side of the transformer. A fault occurs between the motor terminals and the transformer. The symmetrical components of the subtransient current in the motor flowing toward the fault are: I =-0.8-j2.6pu I =-j 2.0pu I =-j3pu From the transformer toward the Fault: I' = 0.8- j0.4pu I =-j1.0pu 1 = 0pu Assume X =X, =X, for both the motor and the generator. (a) Describe the fault type and find the prefault current, if any, in line a. (b) Determine the subtransient fault current in per unit. (c) Calculate the subtransient current in each phase of the generator in per unit taking into consideration the phase shift of the Y-A transformer.

A generator supplies a motor through a Y-A transformer. The generator is connected to Y side of the transformer. A fault occurs between the motor terminals and the transformer. The symmetrical components of the subtransient current in the motor flowing toward the fault are: I =-0.8-j2.6pu I =-j 2.0pu I =-j3pu From the transformer toward the Fault: I' = 0.8- j0.4pu I =-j1.0pu 1 = 0pu Assume X =X, =X, for both the motor and the generator. (a) Describe the fault type and find the prefault current, if any, in line a. (b) Determine the subtransient fault current in per unit. (c) Calculate the subtransient current in each phase of the generator in per unit taking into consideration the phase shift of the Y-A transformer.

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

Chapter3: Power Transformers

Section: Chapter Questions

Problem 3.10P: A single-phase step-down transformer is rated 13MVA,66kV/11.5kV. With the 11.5 kV winding...

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