Line traps prevent transmission of these high frequency signals to unwanted directions without loss of energy at power frequency. Line traps are series-connected to the transmission lines, and are designed to withstand the rated power frequency current and the short circuit current to which the lines are subjected.
What is the function of line trap in the carrier current protection?
Line trap is inserted between the bus-bar and connection of coupling capacitor to the line. It is a parallel LC network tuned to resonance at the high frequency. The traps restrict the carrier current to the unprotected section so as to avoid interference from the with or the other adjacent carrier current channels.
What is the function of line trap and coupling capacitor in carrier current protection?
Line traps are used to restrict the carrier currents within the protected section avoiding interference with or from the adjacent carrier current channels. Coupling capacitors provide an impedance (reactance) of low value to the high-frequency currents.
What is the carrier current protection?
Carrier current protection is the most widely used scheme for the protection of Extra High Voltage (EHV) and Ultra High Voltage (UHV) power lines. The carrier signal is directly coupled to the power line itself which his to be protected.
What is carrier current equipment?
Carrier current transmission, originally called wired wireless, employs guided low-power radio-frequency signals, which are transmitted along electrical conductors. The transmissions are picked up by receivers that are either connected to the conductors, or a short distance from them.
What is the use of line trap?
Line traps prevent transmission of these high frequency signals to unwanted directions without loss of energy at power frequency. Line traps are series- connected to the transmission lines, and are designed to withstand the rated power frequency current and the shortcircuit current to which the lines are subjected.
How does a line trap work?
A line trap, also known as wave trap, or high-frequency stopper, is a maintenance-free parallel resonant circuit, mounted inline on high-voltage (HV) AC transmission power lines to prevent the transmission of high frequency (40 kHz to 1000 kHz) carrier signals of power line communication to unwanted destinations.
Which of the following carrier frequency is used in a carrier current protection scheme?
The signals generated in a carrier-current protection scheme are at a frequency between 50 and 500 kHz.
Which of the following devices is used to protect lines from carrier communication waves?
Protective device
The line trap or wave trap prevents unwanted loss of carrier signal power and also prevents carrier signal transmission to adjacent power lines. Line traps or wave traps are available for narrow-band and wide-band carrier frequency blocking applications.
What is pilot wire protection?
The pilot wire differential relay is a high-speed relay designed for protection of transmission and distribution lines. They are generally applied on short lines, normally less than 40 km long. The scheme requires communication channel (link) to carry system voltage and current information to the control location.
What is Translay relay?
The translay relay is a differential relay. The arrangement is similar to overcurrent relay, but the secondary winding is not closed on itself. These types of relays are used in the feeder protection and the scheme is called Translay scheme.
What is Burden relay?
Solution: Burden in current transformer terminology is the load connected to the secondary terminals and is expressed either as VA (volt-ampere) and power factor at a specified value of current, or as total ohms impedance with the effective resistance and reactive components.
Why wave trap is used in two phases?
The reason for using multiple traps can be due to the need for more than one communication channel to increase the protection security, and/or it can be due to the type of system grounding where shield wires aren’t used, and/or it can be due to reducing signal attenuation on long lines.
Where wave trap is used in substation?
Wave trap is a device which 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.
What is the full form of PLCC?
Power Line Carrier Communication (PLCC) Protection / Transmission and Distribution.
What is line matching unit in PLCC?
LMU is also known as Coupling Device. Together with coupling capacitor, LMU serves the purpose of connecting effectively the Audio/Radio frequency signals to either transmission line or PLC terminal and protection of the PLCC unit from the over voltages caused due to transients on power system.
Which type of back up protection is widely used for protection of transmission lines?
Distance relay: Distance relay is widely used for the protection of high-voltage AC transmission line and distribution lines.
What is the purpose of a power line carrier?
Power-line communication (also known as power-line carrier or PLC) carries data on a conductor that is also used simultaneously for AC electric power transmission or electric power distribution to consumers.
What is a line carrier?
Power Line Carrier means the use of existing electricity wire infrastructure to carry voice and data signals simultaneously by transmitting high frequency data signals through the electric power lines.
What is MHO relay?
Mho relay is a voltage restrained directional relay. Important Points: Reactance relay is suitable for the protection of a short transmission line because its operation is independent of arc resistance. The relay which is selected for a long transmission line should be less affected due to power swings.
What are pilot relays?
Pilot relaying refers to any relaying scheme employing a communication network between relays, at different substations, to transmit “trip or don’t trip” signal. The intent here is to trip the circuit breakers as fast as possible. In the past, the relays communicated over the copper wire that directly tied them.
Why MHO relay is called MHO relay?
A mho Relay is a high-speed relay and is also known as the admittance relay. In this relay operating torque is obtained by the volt-amperes element and the controlling element is developed due to the voltage element. It means a mho relay is a voltage controlled directional relay.
What is Translay system of protection?
Translay protection is applied for the protection of transformer feeders. The name Translay refers to a relay with a transformer feature. It can be also used for the protection of single-phase or 3-phase feeder, and parallel feeders against both earth and phase faults.
What is RX diagram?
The R-X graph shows an apparent impedance which has a complex relationship to the actual Rf depending on the power system conditions. The fault position vs. true Rf graph can remove all of those effects and show the true performance no matter what the power system conditions are.
What is Zone 2 in distance protection?
Zone 2: Mainly intended to cover the remaining 10 % to 20 % of the Protected Line and provide Backup for the Adjoining Lines (50% of the Adjoning Length). It set to cover Remote End Busbar and Hence it is called as an Overreaching Element.
What are the errors of CT?
There are two types of errors in a current transformer. They are ratio error and phase angle error.
What is accuracy limit factor?
The rated accuracy limit factor (Fn) is the ratio of the rated accuracy limit primary current to the rated primary current. A protective current transformer type 5P10 has, for example, the accuracy class 5P and the rated accuracy limit factor 10.
What is the meaning of wave trap?
Definition of wave trap
: a tuned radio circuit used to improve the selectivity of radio apparatus or to eliminate interference.
What is the use of CVT in substation?
CVTs in combination with wave traps are used for filtering high-frequency communication signals from power frequency. This forms a carrier communication network throughout the transmission network, to communicate between substations. The CVT is installed at a point after Lightning Arrester and before Wave trap.
Why you should not abuse power?
Power makes us feel less dependent upon others, freeing us to shift our focus away from others to our own goals and desires. Power corrupts in four ways: Power leads to empathy deficits and diminished moral sentiments. Power leads to self-serving impulsivity.
What is a line matching transformer?
This means a transformer at the source to step-up or match the amplifier impedance to the 100 V line, and then a transformer at each loudspeaker to step-down or match the 100 V line to the loudspeaker impedance. These transformers are known as line-matching transformers.
Which relay is used for 11kv feeders?
ABB Feeder Protection Relay, For Ht Line, 6.6 KV/11 KV/33 KV
| Usage/Application | HT Line |
|---|---|
| Brand | ABB |
| Voltage | 6.6 KV/11 KV/33 KV |
| Current | As Required |
| Number Of Poles | 4 Pole |
How many types of feeders are there?
The six commonly used types of feeder systems are: Step feeder: used to feed small cylindrical or spherical parts. Elevator feeder: able to feed simple parts at varying rates. Flex feeder: uses vison-guided robots for part selection.
What is the most important rule of electrical safety?
For added safety, use a lock to prevent anyone from turning the power back on. Conclusion: Thus, the most important rule of electrical safety is to de-energize the electrical circuit before working on it.
What is the function of relay in fault protection?
The purpose of the protection relay is to detect a problem, ideally during its initial stage, and to either eliminate or significantly reduce damage to personnel and/or equipment.
What are the two commonly used types of unit protection systems?
Two basic arrangements are used for pilot unit protection:
Balanced voltage (see Figure 4), and. Circulating current (see Figure 5).
Which is the advantage of unit type line protection?
a) Unit Protection Scheme: Unit type schemes protect a specific area of the system i.e. a transformer, transmission line, generator or bus bar. The unit protection schemes are based on Kirchhoff’s Current Law – the sum of the currents entering an area of the system must be zero.
What is the principle of pilot wire protection?
The pilot wire differential relay is a high-speed relay designed for protection of transmission and distribution lines. They are generally applied on short lines, normally less than 40 km long. The scheme requires communication channel (link) to carry system voltage and current information to the control location.
What is the purpose of pilot cable?
Pilot cables are used for control, protection, signalling, telecommunications and data transmission purposes associated with power distribution and transmission systems. Such systems are mainly operated by the electrical supply industry and similar applications occur in many industrial systems.
Which relay is used for protection of feeders?
The differential relay is used for the protection of the feeder, large busbars, etc.
Which type of relays are required for full protection of 3 phase line?
For complete protection of a 3-phase transmission line, we require Two-phase and one-earth fault relays.
What are the advantages of power line carrier communication?
The main advantage of power line carrier communication is the reduced cost because of utilizing the existing power lines. In case of a power supply for a whole building, the main cables are dropped through-out the building and it bears all the load thruster by equipment or devices run on electricity.