Line traps stop the transmission of these high frequency signals without reducing their power frequency energy. Line traps are in series with the transmission lines and built to withstand both the short circuit current and the rated power frequency current that the lines are subjected to.
What is the function of line trap used in carrier current protection?
Line traps are an LC network used to confine carrier currents to the protected section and prevent interference from or from adjacent carrier current channels. They are inserted between the busbar and connection of coupling capacitors to the line and tuned to resonance at the high frequency.
What is the function of line trap in the carrier current protection Mcq?
In a lengthy transmission line, a line trap is utilized to
d) safeguard the line from direct lightning strikes. Correct response: (c) limit the carrier signals to the line.
What is the function of line trap and coupling capacitor in carrier current protection?
In order to prevent interference with or from the adjacent carrier current channels, line traps are used to limit the carrier currents within the protected section. A low value impedance (reactance) is offered by coupling capacitors to the high-frequency currents.
What is mean by carrier current protection?
The main purpose of a carrier current protection scheme is to safeguard long transmission lines. Instead of comparing the actual current, the phase angle of the current at the two phases of the line is compared in carrier current protection schemes.
What is the purpose of line trap?
HV transmission lines are linked in series with line traps. The line trap’s primary job is to offer a significant impedence at power-line carrier frequencies (30-500 kHz) while posing a negligible impedence at power frequency (50 or 60 Hz).
How does a line trap work?
A line trap, also referred to as a wave trap or high-frequency stopper, is a parallel resonant circuit mounted inline on high-voltage (HV) AC transmission power lines to stop the transmission of high frequency (40 kHz to 1000 kHz) carrier signals of power line communication to unauthorized locations. Line traps are maintenance-free devices.
Which of the following carrier frequency is used in a carrier current protection scheme?
A carrier-current protection scheme generates signals between 50 and 500 kHz in frequency.
What is the purpose of power line carrier communication?
In order to communicate, protect, and monitor electrical substations remotely, power lines at high voltages, such as 110 kV, 220 kV, and 400 kV, are used for power-line carrier communication (PLCC). Amplitude modulation is typically the modulation type used in these systems.
Which type of relay is used for protection of transmission line?
The type of protection relay most frequently used for transmission line protection is a distance relay. Distance relays operate in response to variations in the ratio of measured current and voltage, measuring the impedance from the installation side to the fault location.
What is pilot wire protection scheme?
A high-speed relay created for transmission and distribution line protection is the pilot wire differential relay. Typically, they are used on short lines that are under 40 km in length. The communication channel (link) needed by the scheme is to transmit data about system voltage and current to the control location.
What is field suppression?
Suppression of Fields
When an alternator winding fault occurs, the C.B of the device trips, allowing stored energy in the field to be discharged through a resistor.
What trap is used to trap waves of?
Higher frequencies entering generator or transformer units is the correct response.
What is a power trap?
The RatX® Power Trap is a substantial, long-lasting trap that is ideal for use around the house, barn, garage, etc. for anyone searching for a trap that will effectively catch rats. Rats and mice can be drawn to the trap by being sprayed with RatX® Attractant. Perfect for use inside or outside.
What is line matching unit in PLCC?
LMU also goes by the name Coupling Device. LMU and coupling capacitor work together to effectively connect audio and radio frequency signals to transmission lines or PLC terminals while also protecting the PLCC unit from overvoltages brought on by transients in the power system.
What is the full form of PLCC?
Transmission, distribution, and protection for Power Line Carrier Communication (PLCC).
Which instrument is present in the power line carrier communication system?
The device used in power line carrier communication systems is known as a tuning unit or line tuner.
What is the use of CVT in substation?
High-frequency communication signals are filtered from power frequency using CVTs in conjunction with wave traps. In order to communicate between substations, this creates a carrier communication network throughout the transmission network. The CVT is installed just before the wave trap and just before the lightning arrestor.
What is distance protection of transmission lines?
A non-unit system of protection called distance protection measures the impedance between the relay location and the location where the fault occurs and compares it to the set value. The relay operates and isolates the defective section if the measured impedance is less than the set value.
Which type of relays are used for the protection of parallel feeders?
Relays are needed at both the source end and the load end to protect parallel feeders fed from one end. The source end relays must be non-directional.
What are the requirements of protection of line?
The following conditions must be met by the protection strategy: a) The breakers are not typically tripped under normal circumstances. b) Only the breakers on the source side that are most near the fault trip when there is a fault. c) The next breaker closer to the source should trip if the closest one malfunctions.
What is a line carrier?
Power line carrier refers to the practice of transmitting high frequency data signals through existing electrical power lines to simultaneously carry voice and data signals.
What is the principle of power line communication?
The following is the fundamental tenet of power line communication. Data is modulated on the transmitter when it is being sent between two devices, and the modulated signal is then superimposed on the AC or DC power supply voltage.
What are the advantages of power line carrier communication?
Because existing power lines are being used, the main benefit of power line carrier communication is the lower cost. When a building needs a power supply for the entire structure, the main cables are run throughout the structure and they support all the weight of the electrical equipment and devices.
What is a power line network?
a data network that connects through common wall outlets and uses the electrical system of a building as the transmission medium. To expand a wired Ethernet network into a different room, this method is frequently used.
Which is the main relay for protecting long transmission line?
Relay MHO:
These relays are employed in the detection of phase faults in long transmission lines and at the location of synchronizing power surges. Being a combined unit of direction and distance measurement, the mho relay is more sensitive and reliable.
What is function of Buchholz relay?
There will typically be two sets of contacts on a Buchholz relay. In the event of a severe internal fault, one is set up to work for slow gas accumulations and the other for large-scale oil displacement. The latter is typically wired directly to the circuit breaker trip relay, while the former generates an alarm.
What is Mho relay?
A voltage-restrained directional relay is the Mho relay. Important Information Because reactance relays operate independently of arc resistance, they are ideal for protecting short transmission lines. Relays chosen for long transmission lines should be less impacted by power fluctuations.
What is Burden relay?
The load connected to the secondary terminals of a current transformer is referred to as a burden. Its impedance is expressed as either total ohms with the effective resistance and reactive components, or as VA (volt-ampere) and power factor at a given value of current.
What is busbar differential protection?
Differential Protection currently. Kirchoff’s current law, which states that the total current entering and leaving an electrical node must be exactly equal, is a component of the busbar protection scheme. As a result, the amount of current entering and leaving a bus section is the same.
What is Solkor protection?
In situations where solid metallic pilot wires are available, Solkor unit protection is used. The system, known as Solkor R/Rf, is a differential protection system. Pilot wire supervision and injection intertripping systems are available extras. There are two ways to configure Solkor protection.
What causes loss of excitation?
Loss of excitation (LOE), which can be brought on by a field winding short circuit, an unexpected field breaker opening, or faulty LOE relay operation, is a very frequent fault in the operation of synchronous machines. A statistic from China indicates that 69.5% of all generator failures are attributable to LOE [1].
Which relay is used for loss of excitation?
Alternator Loss of Excitation:
As a result, the loss of excitation scheme is set up to trip with the aid of an offset mho relay that is powered by the generator terminals’ AC current and voltage.
What is Carrier current distance relay?
The transmitter at the far end of the line transmits carrier current to the receiver, which then receives it. The receiver transforms the transmitted carrier current into a DC voltage that can be applied to a relay or other circuit to accomplish any desired task.
Why you should not abuse power?
Being in a position of power allows us to feel less reliant on other people, which allows us to turn our attention inward toward our own objectives. Four ways exist for power to corrupt: Lack of empathy and weakened moral sentiment are caused by power. Power breeds impulsive self-interest.
What is the difference between CVT and PT?
PTs are not intended for such high values, whereas CVTs are rated for high voltage levels above 100 kV.
What is a line matching transformer?
This entails using a transformer at the source to step-up or match the amplifier impedance to the 100 V line, and then using a transformer at each loudspeaker to match the impedance of the 100 V line to that of the loudspeaker. Line-matching transformers are what these transformers are called.
What is the function of bypass capacitor?
A bypass capacitor is what? Bypassing the noise to the ground, a capacitor is used to stop it from entering the system. To lessen power supply noise and voltage spikes on the supply lines, it is connected between the supply voltage (Vcc) and ground (GND) pins.
Where are coupling capacitors used?
Circuits for amplifiers must include coupling capacitors. They are used to stop AC signals from interfering with a transistor’s bias voltage. This is accomplished in the majority of amplifier circuits by passing the signal through a coupling capacitor and into a transistor’s base terminal.
What is difference between PT and VT?
A power transformer changes the voltage from one level that is unsuitable for the load or for further transmission to another level that is. For use by metering and protection equipment, a voltage transformer always steps down a higher voltage to a lower voltage.
What is VT ratio?
Performance of a transformer is gauged by the VT Ratio, also known as the Voltage Transform Ratio. In the electrical industry, it is one of the most popular techniques for figuring out how much power a particular transformer can handle. The voltage loss during transmission through the transformer is indicated by the VT Ratio.
What are the different types of protection used in generator?
This class’s various protections include:
Disparity in the poles on the HV side of the generator transformer. Protection for the generator’s negative phase sequence. Protection from Earth fault and overcurrent in the generator transformer. protection against reverse power without turbine trip.
What is line differential protection?
One of the most common types of transmission line protection is line differential protection. Kirchoff’s current law, which states that the current flowing into a line must equal the current flowing out of the line, is the foundation for this type of protection.
Why distance protection is used?
The primary or main protection and backup protection for AC transmission lines and distribution lines against three phase faults, phase-to-phase faults, and phase-to-ground faults are frequently provided by distance protection schemes.