Line traps are used in Power Line Carrier Communication (PLCC) systems. The line trap is also known as a wave traps.
Line trap is connected in series with transmission line. Line Traps are inserted into high voltage AC transmission lines to prevent undue loss of carrier signal power (40 kHz to 500 kHz) under all power system conditions. It is a parallel resonant circuit which offers high impedance at the tuned frequency by connecting a tuning device in parallel with the main coil.
line trap allows the passage to power frequency current & block the high frequency currents, The main function of the Line Trap is to present a high impedance at the carrier frequency band while introducing insignificant impedance at the power frequency itself. Line Traps for Power Line Carrier (PLC) communication systems represent a significant application segment for high voltage inductors.
Usually wave trap is located at entrance of substation in incoming line. As communication waves are high frequency they will act as harmonics towards electrical equipment’s like transformer, breaker etc., So in order to protect them we should connect at entrance (after the CVT) so that wave trap will trap the communication waves.
The wave trap is an assembly of three main components:
1. Main Coil
2. Tuning Device
3. Protective Device
1. Main Coil: the mail coil carries a rated current of a transmission line and t is design to withstand a maximum short circuit current.
- Class F insulation
- Low Temperature stress
- Lowest losses-High Q Factor
2. Tuning Device: The tuning device can be single band tuned or programmable for multiple bands. it is blocking a impedance or blocking resistance over a specified frequency range of power line carrier channel.
Features of line traps
- Used for 72 kV to 800 kV
- Current rating 200 A to 6500 A
If any query or suggestion about line traps please comment below or Email on Dipak@electricalidea.com.