Reactance relay is normally preferred for protection against
- A. Over load currents only
- B. Phase faults only
- C. Earth faults only
- D. High voltage protection only
Answer: C. Earth faults only
Explanation: Reactance relays measure only reactance (X) and are unaffected by fault arc resistance (R), making them the preferred choice for earth fault protection on short lines where arc resistance is relatively large.