Wave trap is used to create a high impedance to the carrier wave high-frequency communication entering into unwanted destinations typically substations.
Carrier wave communication uses up to 150kHz to 800kHz frequency to send all the communication.
These high-frequency damages the power system components which are designed to operate 50 or 60 Hz. Wave traps are also called line traps.
The main coil is an inductor that is connected directly to the high voltage power frequency line.
The tuning pack consists of a capacitor connected across the main coil to tune the line trap to the desired blocking frequency. A surge arrester is used to protect the line trap from damage due to transient over-voltages.
Wave trap is a device that prevents the high-frequency carrier signals to enter the substation side. It is also known as line trap. It is connected in series with the transmission line.
It is designed to carry the rated power frequency (50 Hz or 60 Hz) current, as well as to withstand the substation fault currents.
It consists of an inductor coil that is connected in series with the high voltage power system.
Line traps are connected in series with the power lines and thus their coils are rated to carry the full line current.
The impedance of a line trap is very low at the power frequency and will not cause any significant voltage drop.
Wave trap Components
1. Main coil
2. Terminal
3. Corona ring
4. Corona cap
5. Bird barrier
6. Tuning pack
7. Surge arrester
8. Winding spider (cross arm)
Wave trap Applications
1. Line Traps are used in power line communications to prevent undue loss of carrier signal power and to minimize interference from carrier signalling systems on adjacent transmission lines.
2. They are inserted in series in a power transmission line in order to confine the high-frequency carrier signal to the appropriate line sections.
3. They present a high impedance at the carrier frequency band (40 to 500 kHz) thus preventing signal power loss. In addition, the impedance at the power frequency (50 Hz or 60 Hz) is negligible, in order to avoid interfering with the power transmission.
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