Question

The line trap unit employed in carrier current relaying offers

• A. High impedance to 50 Hz power frequency signals
• B. High impedance to carrier frequency signals
• C. Low impedance to carrier frequency signals
• D. Low impedance to 50 Hz power frequency signals

Hint:

Line traps isolate communication signals from power equipment in substations.

Answer 1

The Correct Option is B

Line traps are installed to block high-frequency carrier signals from entering the substation equipment. They provide high impedance at carrier frequencies (typically 50–500 kHz), while allowing 50 Hz power frequency signals to pass freely.