A 500 kVA, 6.6 kV star connected alternator has a synchronous reactance of 1.0 2 per phase and negligible resistance. The differential relay operates if the out of balance current through it exceeds 30% of the normal full load current of the alternator. The star point of the alternator is earthed through a resistance of 5 2. What percent of the stator winding is left unprotected? Show that the effect of the alternator reactance can be neglected.

A 500 kVA, 6.6 kV star connected alternator has a synchronous reactance of 1.0 2 per phase and negligible resistance. The differential relay operates if the out of balance current through it exceeds 30% of the normal full load current of the alternator. The star point of the alternator is earthed through a resistance of 5 2. What percent of the stator winding is left unprotected? Show that the effect of the alternator reactance can be neglected.

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

Chapter11: Transient Stability

Section: Chapter Questions

Problem 11.8P

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