Line Traps / Wave Traps

LINE TRAPS / WAVE TRAPS



Line traps are used in Power Line Carrier Communication (PLCC) systems. 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, the attenuation and high frequency impedance characteristics of the power line can be made.

The line trap is an assembly of three main components:
1. Main Coil
2. Tuning Device
3. Protective Device


The line trap is an assembly of three main components:
1. Main Coil
2. Tuning Device
3. Protective Device


Main Coil
The line traps manufactured by Quality Power are of resin
encapsulated design.

  • Rugged Construction as per IEC 60353
  • Dry Q Coil Technology
  • Class F Insulation.
  • Lowest losses.
  • Low Temperature stress
  • Compact Dimensions & Adaptable Mounting Features
  • Lower weights
  • Silicon coated RTV resin coat
  • Coated with UV resistant special polyurethane paint

Tuning Device
Tuning device is connected in parallel with main and protective device. It provides blocking impedance over a specified frequency range. It can be sing band tuned or multiple bands. The tuning circuit is enclosed in weather proof enclosures filled with resin/foam to protecting from weather conditions.

  • High Quality Tuning components
  • High Frequency Performance
  • Resin Encapsulated
  • Dielectrically tested
  • Narrow band / broad band
  • Multiple Tuning in single pot
  • Compact and sturdy

Protective Device
Protective device ensures protection of tuning device and main coil against surge voltages.

  • Transient Overvoltage Protection
  • Polymer Construction
  • Light and compact

The line trap is connected in series with the transmission line. The main coil is designed to carry the rated power frequency current as well as to withstand the fault levels of sub-station equipment. It allows the passage to power frequency currents and block the high frequency currents with the help of tuning circuit. The tuning circuit in conjunction with the inductance of the mail coil forms a band stop filter. It ensures that the line trap offers high impedance to carrier currents under all conditions including resonance.

The tuning circuit can be single band tuned or programmable for multiple bands (usually two to three bands). The tuning circuit is housed in a weather proof enclosure filled with resin/foam to prevent it from the weather conditions.

The lightning arrester ensures protection against surge voltages. The lightning arrester can be gapless or gapped type. The line traps conform to IEC standard 60353.

The tapping losses are calculated by the following formula:

Tapping loss based on the blocking resistance (A+R)
= 20 log10 (U1/U2) dB
= 20 log10 [1+(Z1/2Rb)]dB
Blocking Attenuation based on blocking resistance.
Blocking Attenuation = 20 log [1+(Rb/Z1)]

Where:
Z1 = Resistance equivalent to the characteristic impedance of the line
Rb = Blocking resistance The line traps manufactures by Quality Power are of encapsulated design. This design does not require spacers between each turn of the main coil. Further, they are low loss type thereby reducing the transmission loss and saving for the customer. The low loss line trap produce less heat resulting into longer life for the insulation and the line trap.

Terminal Holes Pattern
Standard 4 hole NEMA flat aluminum terminals are provided. However, this can be customized in line with customer requirements.

Bird Barriers
Bird barrier is provided as an optional accessory for protection against bird and environment.

PLCC (Power Line Carrier Communication)
Power Line Carrier Communication (PLCC) is the technology used for communication among electrical substations through existing transmission lines.

PLCC is thus very useful technology for transmitting the signals, mainly for telecommunication, tele-monitoring & protection between stations through high voltage power lines.

Line Traps in PLCC
The wave traps performs the task of directing the carrier energy on the transmission line towards the remote line terminal and not towards the station bus, isolating it from bus impedance variations. The wave trap is usually a form of a parallel resonance circuit, which is tuned to the carries energy frequency.

A parallel resonant circuit has high impedance as its tuned frequency, and it then causes most of the carrier energy to flow towards the remote line terminal. The coil of the wave trap provides a low impedance path for the flow of the power frequency energy.

Since the power flow is rather large at times, the coil used in a wave trap must be large in terms of physical size.

Once the carrier energy is on the power line, any control of the signal has been given over to nature until it reaches the other end. During the process of travelling to the other end the signal is attenuated, and also noise from the environment is added to the signal. At the receiving terminal the signal which is decoupled from the power line in much the same way that is was coupled at the transmitting terminal. The application of each of the components of the PLC channel must be considered carefully in order that the system operates properly.

Line Trap
Line trap also known as Wave Traps a critical component of PLCC. Wave trap filters the high frequency communication signals sent on the line from the remote substation and diverts them to the telecom/tele-protection panel in the substation control room (through coupling capacitor and LMU).

Line trap is connected in series with transmission line. Quality Power designs & manufactures Line Trap main coil in such a way to carry the rated power frequency current as well as to withstand the higher fault levels of sub-station equipment.

It allows the passage to power frequency current & block the high frequency currents with the help of tuning circuit. The tuning circuit is in conjugation with the inductance of the main coil forms a band stop filter. It ensures that the line trap offers high impedance to carrier current under all conditions including resonance.


Design & Construction – Line Trap
Line Trap is parallel resonant circuit which offers high impedance at tuning frequency by connecting a tuning device in parallel with the main coil. Thus, Line Trap is an assembly of three major components to serve its purpose.

1. Main Coil
2. Tuning Device
3. Protective Device

Line Trap Main Coil
Line Trap is parallel resonant circuit which offers high impedance at tuning frequency by connecting a tuning device in parallel with the main coil. Thus, Line Trap is an assembly of three major components to serve its purpose.

  • Characteristic of QP make Line Traps
  • Self resonant frequency >500KHz
  • Class F insulation
  • Lowest losses-High Q Factor
  • Low Temperature stress
  • Compact Design
  • Lowest Weight
  • Silicon coated RTV resin coat
  • Multiple mounting options
  • Coated with UV resistance special polyurethane paint

Tuning Circuit
The tuning device connected in parallel with main coil & protective device. It provides a defined blocking impedance or blocking resistance over a specified frequency range of power line carrier channel. The tuning device is installed inside the main coil. The tuning device can be single band tuned or programmable for multiple bands (usually two or three bands). The tuning circuit is housed in weather proof enclosure filled with resin/foam to protect it from the weather conditions.

  • Variable Multiband Tuning
  • High frequency performance
  • Resin Encapsulated
  • Dielectrically tested
  • High Temperature withstand ability
  • Multiple Tuning in single pot
  • Compact and sturdy
  • Wide band tuning device.

Components in Tuning Circuit
Tuning circuit device is made of several combinations of Capacitors, Resistors & Inductors connected in Series/Parallel connection of comparative low power ratings.

The composite tuning device is housed inside fiberglass with resin impregnation to withstand higher temperature rise.

Characteristic of Various Blocking Brands :
  • Damped Narrow Frequency Tuning
  • Damped Wide Frequency Tuning
  • Un-damped Narrow Frequency Tuning
  • Protective Device

The protective device ensures protection of tuning device and main coil against surge voltages. Quality Power provides Line Traps equipped with Metal Oxide Lightning/ Surge Arrestor which are connected in parallel with Line Trap and Tuning device.

Surge Arrestor equipped with Line Traps & Tuning device protects them by reducing the transient excess voltages to corresponding distribution voltage level.

Proper insulation coordination between mail coil insulation level and the surge arrestor characteristic is achieved to ensure reliable protection.

Characteristics:
  • Complying with IEC 60099
  • Transient Overvoltage Protection
  • Polymeric construction
  • Light & Compact

Mounting of Line Traps
Quality Power Line Traps are configured with number of mounting options say, Pedestal Mounting, Suspension Mounting CVT Head & Horizontal Mounting.

Quality Power provides Pedestal Mounting with respect to general mounting specifications. Mounting options as follows-

Pedestal Mounting
Tripped Structure Mounting (BPI Mounting)

Suspension mounting
CVT Head Mounting
Horizontal Mounting - Mounting of Line Trap
in horizontal Axis

Accessories-Quality Power generally provides the Line Traps with following accessories either Mandatory/Optional on request.
1. Bird Barrier
2. Suspension Pins (Mandatory/Optional)
3. Pedestal (Mandatory/Optional)
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