Lecture 9 Current Based Relaying Scheme-IV

In continuation of the previous lecture, the application of overcurrent relays for transmission line protection is discussed. Then, different protection philosophy of relay i.e. Current discrimination or Current graded, Time discrimination or time graded, and Current-Time discrimination, have been covered in this lecture. Subsequently, the application, along with its advantage and disadvantage, is discussed with proper justification. Further, the procedure to select the setting of phase and ground relays is also explained.