How Line Traps or Wave Traps works ? Explained | TheElectricalGuy

Summary

Key Points

• —Power frequency signals operate at 50 or 60 Hz, while communication signals used in PLCC range from 40 kHz to 500 kHz. 0:56
• —PLCC is economical because it utilizes existing transmission infrastructure to transmit voice, data, remote metering, and control signals. 1:10
• —Transmission lines are used not only for power delivery but also for transmitting communication signals between substations via a method called Power Line Carrier Communication (PLCC). 1:18
• —High-frequency communication signals must be blocked from entering substations to prevent adverse effects on equipment designed for power frequencies. 3:02
• —Wave traps work by providing high impedance to high-frequency communication signals while offering very low impedance to power frequency signals. 4:25
• —The primary component of a wave trap is a large inductor (main coil) connected in series with the transmission line, which creates inductive reactance proportional to frequency. 10:00
• —A tuning device, typically an RLC circuit, is connected in parallel with the main coil to precisely set the frequency range that the wave trap will block. 10:00
• —A lightning arrester or spark gap is included in parallel with the tuning device to protect it from overvoltages. 10:17
• —Blocked communication signals are diverted through a parallel path, usually a capacitive voltage transformer (CVT) or coupling capacitor, which offers low impedance to high frequencies. 13:46
• —CVTs serve a dual purpose, acting as instrument transformers for voltage monitoring and relaying, and as a coupling point for PLCC equipment. 14:53