Protection Engineering Basics and Schemes Protection Engineering | Page 199
I 2 start flowing towards faulty equipment, now i 1 and i 2 both are in same direction, and ∆I is greater than zero / user defined. On this situation protection relay activated to isolates unit / section at which Differential protection employed.
In generator, motors we can apply same CTs on both side for differential protection
but for transformers the ratio of CTs are different. This arrangement is due to different voltage level at both side of transformer.