194Rated and setting currentsIn = rated current of current transformerI> = setting value of overload current (51)I>> = setting value of short-circuit current (50)Io> = setting value of earth fault current (first threshold) (51N)Io>> = setting value of earth fault current (second threshold) (50N)(1) If an external toroidal current transformer is used, recalculate the setting values according to its primaryrated current.Current Protection functionstransformer (CT)In I> I>> Io> Io>>[A] 0.2 ... 1 x In [A] 2.5 ... 20 x I> [A] 0.1 ... 1 x In [A] (1) 2.5 ... 20 x Io> [A] (1)40 8 ... 40 20 ... 800 4 ... 40 10 ... 80080 16 ... 80 40 ... 1600 8 ... 80 20 ... 1600100 20 ... 100 50 ... 2000 10 ... 100 25 ... 2000150 30 ... 150 75 ... 3000 15 ... 150 37.5 ... 3000200 40 ... 200 100 ... 4000 20 ... 200 50 ... 4000250 50 ... 250 125 ... 5000 25 ... 250 62.5 ... 5000600 120 ... 600 300 ... 12000 60 ... 600 150 ... 120001250 250 ... 1250 625 ... 25000 125 ... 1250 32.5 ... 25000

ABB PR512 Manual