Protection Engineering Basics and Schemes Protection Engineering | Page 214

m = 0. 2

2 = 0. 1 But considering situation and requirement as Tap positions are-15 % and + 5 % and let suppose our CT error is 5 %, We select m = 25 %, then

m 1 = 25 % I diff = 0.2A I rest = 2A

m 2 = 50 %, at this point our I res = 2.5( I full) then I res = 2.5 ∗( 349.91)

I res = 2.1869A But we select I rest = 2.5A

m 2 = I diff

I res

50 % = I diff 2.5

I diff = 1.25A pg. 214