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A transmission system is employed with pilot relaying schemes for protection. Pilot is a channel which transmits the information from one end of the transmission line to the other.The information is normally an electrical quantity that is measured at both the ends. The different pilots used are wire pilot, carrier-current pilot and microwave pilot.
Solkar system ( reyrolle) is a scheme employing the wire pilot. It is commonly called the balanced voltage or opposed voltage scheme. It operates on the principle of current differential protection.
Further details in Protection and Switch gears by Badri Ram and Viswakarma.
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What factor cause spill current on external fault in case of transformer differential protection?
Spill current during an external fault in transformer differential protection is primarily caused by the unequal impedance in the transformer windings and the connected power system. When an external fault occurs, the fault current flowing through the transformer can create a differential current between the primary and secondary windings due to their differing voltage drops and phase shifts. Additionally, the presence of harmonics and the effects of CT (current transformer) saturation can further contribute to this spill current, complicating the differential relay's ability to distinguish between internal and external faults.
Why do we use current sources as load in differential amplifiers?
Current sources are used as loads in differential amplifiers to improve their performance by providing high output impedance, which enhances the gain of the amplifier. They also help in maintaining a constant current through the differential pair, ensuring better linearity and increased common-mode rejection ratio (CMRR). This results in improved signal integrity and noise immunity, making differential amplifiers more effective for applications requiring precise signal amplification.
What is a line differential protection?
Differential protection for power transmission systems comes down to looking at power coming into a location and power leaving that location; if these are equal, then everything is OK. If these are not equal, meaning power is going in and not coming back out, this indicates a fault condition. An example of differential protection is for a substation bus. current transformers are connected to the bus differential from every power sourch into and out of the bus. The bus differential adds all the currents up, and the sum should be zero. If it is not, this means current is flowing into the bus but not leaving, meaning it is going to ground somewhere. A line differential is the same concept as a bus differential. It's simply covering a line, which can be many miles long, so usually two relays are used, connected by a high speed communication path such as fiber optic cable. The current flowing in one side should be equal to the current flowing out the other.
What is differential transformer protection?
The current input (primary) to a transformer is proportional to the output (secondary) current. Differential protection relays monitor these via current transformers (CT). The percentage of difference between primary and secondary can be adjusted. If it is over the seting the relay will trip the primaryand secondary feeder breakers. Thus indicating an inbalance between internal phasewindings and or shorts to earth.
What is the difference between diffrencial relay and a distance relay?
They're completely different, used for different applications (usually). A distance relay uses both current and voltage. A differential relay uses only current. A differential relay usually has harmonic restraint capability, while distance relays ideally track system frequency. Differential relays require fast operation, while distance relays may not be required to operate as quickly. Distance relays have more issues with operating for out of zone problems than differential relays. There are many more, but this gives an idea.
When was Eknath Solkar born?
Eknath Solkar was born on March 18, 1948, in Mumbai, India.
Dear all what direct consequences can be from Current transformer on generator with respect to differential protection relay?
CT's are used as inputs to the differential. If the CT is bad, or it is not wired to the differential correctly, it will cause differential current to be seen by the relay, resulting in a trip.
What factor cause spill current on external fault in case of transformer differential protection?
Spill current during an external fault in transformer differential protection is primarily caused by the unequal impedance in the transformer windings and the connected power system. When an external fault occurs, the fault current flowing through the transformer can create a differential current between the primary and secondary windings due to their differing voltage drops and phase shifts. Additionally, the presence of harmonics and the effects of CT (current transformer) saturation can further contribute to this spill current, complicating the differential relay's ability to distinguish between internal and external faults.
What is the type of generator protection to protect against unequal phase current?
differential protection
Why do we use current sources as load in differential amplifiers?
Current sources are used as loads in differential amplifiers to improve their performance by providing high output impedance, which enhances the gain of the amplifier. They also help in maintaining a constant current through the differential pair, ensuring better linearity and increased common-mode rejection ratio (CMRR). This results in improved signal integrity and noise immunity, making differential amplifiers more effective for applications requiring precise signal amplification.
What is the use of resistor in the circuit?
A resistor develops a voltage differential when current is passed through it. Ohm's law: Voltage is current times resistance.
What is a line differential protection?
Differential protection for power transmission systems comes down to looking at power coming into a location and power leaving that location; if these are equal, then everything is OK. If these are not equal, meaning power is going in and not coming back out, this indicates a fault condition. An example of differential protection is for a substation bus. current transformers are connected to the bus differential from every power sourch into and out of the bus. The bus differential adds all the currents up, and the sum should be zero. If it is not, this means current is flowing into the bus but not leaving, meaning it is going to ground somewhere. A line differential is the same concept as a bus differential. It's simply covering a line, which can be many miles long, so usually two relays are used, connected by a high speed communication path such as fiber optic cable. The current flowing in one side should be equal to the current flowing out the other.
What is solkar protection?
Solkar protection refers to a protective coating or film applied to surfaces, particularly in the context of solar panels and glass. This technology enhances durability, reduces wear and tear, and improves efficiency by minimizing dirt and grime accumulation. It is often used in solar energy applications to ensure that panels maintain optimal performance by maximizing sunlight absorption.
What is differential transformer protection?
The current input (primary) to a transformer is proportional to the output (secondary) current. Differential protection relays monitor these via current transformers (CT). The percentage of difference between primary and secondary can be adjusted. If it is over the seting the relay will trip the primaryand secondary feeder breakers. Thus indicating an inbalance between internal phasewindings and or shorts to earth.
What is the definition of differential relay and how does it function?
In power transformer, a differential relay is a relay that verifies the balance of current between the primary and the secondary face of a transformer. It is also employed in other components of the power system like in protecting cables. Differential relay is also called a unit protection.
What is the three basic types of eddy current coils?
The three basic types of eddy current coils are absolute, differential, and bridge coils. Absolute coils measure the absolute impedance or phase angle change of the eddy current probe. Differential coils measure the slope or rate of change of impedance, while bridge coils compare the impedance changes between two coils.
Differential CT on live and neutral terminal?
A differential CT measures the difference in current between two terminals. When placed on the live and neutral terminals, the CT will detect any imbalance in current flow between them, which can indicate faults or leakage to ground in the system. This can be used for protective relaying or ground fault detection applications.
