Answer / thrimurthy

over current meance nothing but a current reaches above the
rated CT Ratio. and over load and fault occur in between 2
lines line to line short circuit it is over currein fault.

Earth fault means fault occur between line to ground is
called Earth fault. used in power system

Answer / k.prakashchandra

It is 2 OCR + EFR scheme for line protection.Usually OCR is
provided for R & B phases and EFR is connected between the
star point of CTs and star point formed by OCRs (R & B
phases) and direct lead from the third CT (Y phase). R &B
phase ct currents through the OCRs, and Y phase ct current
directly form the second star point.

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