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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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Which component used in Carrier current protection?
Line trap
Coupling capacitor
Trans receiver
All of above
All of above
Quick Summary: Carrier current protection (PLC) relies on a communication link established over high-voltage transmission lines to relay protection signals. The system requires multiple specialized components, including line traps, coupling capacitors, and transceivers, to isolate, inject, and process the high-frequency signals.
Carrier current protection (PLC) relies on a communication link established over high-voltage transmission lines to relay protection signals. The system requires multiple specialized components, including line traps, coupling capacitors, and transceivers, to isolate, inject, and process the high-frequency signals.
fc=2πLtrapCtrap1 — Represents the resonance frequency of the trap circuit to block carrier signals.
Xc=2πfcCcouple1 — Represents the reactance offered by the coupling capacitor to high-frequency signals.
The line trap acts as a band-stop filter, preventing the high-frequency carrier signal from entering the substation equipment while allowing power frequency currents to pass. The coupling capacitor blocks the high voltage (HV) from the carrier equipment while permitting the passage of the high-frequency signal. Finally, the trans-receiver modulates/demodulates and processes these signals to perform tripping or blocking functions in protection relays.
Carrier current protection operates in the range of 30 kHz to 500 kHz.
The Line Trap is connected in series with the phase conductor.
Coupling capacitors are usually connected between phase and ground via a matching unit.
Carrier communication allows for directional comparison and distance protection schemes.
Utilizes existing power transmission lines, eliminating the need for separate communication cables.
High reliability for long-distance protection schemes.
Susceptible to high-frequency noise generated by switching operations or fault arcs.
Signal attenuation increases with length of the transmission line.
Directional comparison protection for EHV lines.
Inter-tripping of circuit breakers in remote stations.
The coupling capacitor serves as a high-pass filter for the carrier signal.
The line trap is specifically tuned to the carrier frequency to create high impedance, forcing the carrier signal to remain within the protected zone.
D is correct — All listed components (Line trap, Coupling capacitor, and Transceiver) are integral parts of a Power Line Carrier (PLC) protection system.
Always remember that the Line Trap acts as a parallel resonant circuit (high impedance) at carrier frequencies, while the Coupling Capacitor acts as a series connection (low impedance) for these frequencies.