If the fault current is 100A at the secondary side of CT having a ratio of 400:5, for an IDMT relay with plug setting of 125% and time of operation is 5 sec for PSM = 12, 4 sec for PSM = 16, 3 sec for PSM = 20, Where, PSM is plug setting multiplier If the actual time of operation is 0.4 sec, then the value of Time Multiplier Setting is

If the fault current is 100A at the secondary side of CT having a ratio of 400:5, for an IDMT relay with plug setting of 125% and time of operation is 5 sec for PSM = 12, 4 sec for PSM = 16, 3 sec for PSM = 20, Where, PSM is plug setting multiplier If the actual time of operation is 0.4 sec, then the value of Time Multiplier Setting is

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 7.1MCQ

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A- An IDMTL relay which having a plug setting PS= 125% , and TMS=0.5 is connected to a supply circuit through a C.T of 400/5 ratio. If the fault current is 2000A and from the characteristics of the relay as shown in the figure below: Determine directly the time of operation of the relay. 19 9 6 4 Time multiplier setting 1.0 0.9 0.8 0.7 0.6 0.5 F0.4 03 0.6 0.5 0.2 0.4 0.3 0.1 0.2 4 5 6 7 8910 Current (multiples of plug setting) 2 3 20 30 Operating time (seconds)
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