A star connected three phase, 10 MVA, 6.6 kV, alternator is protected by Merz-price circulating current principle using 1000/5 amperes current transformers. The star point of the alternator is earthed through a resistance of 7.5Ω. If the min. operating current for the relay is 0.5A. Calculate the percentage of unprotected stator winding when machine is operating at normal voltage.

A star connected three phase, 10 MVA, 6.6 kV, alternator is protected by Merz-price circulating current principle using 1000/5 amperes current transformers. The star point of the alternator is earthed through a resistance of 7.5Ω. If the min. operating current for the relay is 0.5A. Calculate the percentage of unprotected stator winding when machine is operating at normal voltage.

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

Chapter14: Power Distribution

Section: Chapter Questions

Problem 14.8P

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