A 60 MVA, 3 phase, 11 kV synchronous generator is protected by the Merz-Price protection using 1000/ 5 ratio CT's. It is provided with restricted earth fault protection with the earthing resistance of 9.5Ω.Calculate the percentage of winding unprotected in each phase against earth faults if the minimum operating current of the relay is 0.5 A.

A 60 MVA, 3 phase, 11 kV synchronous generator is protected by the Merz-Price protection using 1000/ 5 ratio CT's. It is provided with restricted earth fault protection with the earthing resistance of 9.5Ω.Calculate the percentage of winding unprotected in each phase against earth faults if the minimum operating current of the relay is 0.5 A.

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

Chapter7: Symmetrical Faults

Section: Chapter Questions

Problem 7.34P

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