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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 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.
What is defrential protection relay?
I am going to assume that you are asking about a differential relay. It is basically just that- it compare two different sources and will trip at a set value value of the difference. These can be directional as well. A couple of examples are transformer protective relays and bus differential. A transformer relay will measure the amount of current coming into the transformer and the amount of current going out. If there is a disparity due to an internal fault the relay will trip the supply source and deenergize the transformer. Same for the Bus differential.
Define the term input offset current?
On a differential amplifier while there is some voltage offset there is also current offset which is dependent on the value of the F/B resistance the bigger value the more offset.
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 is the type of generator protection to protect against unequal phase current?
differential protection
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 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.
Why output of common emitter amplifier is inverted?
In a common emitter amplifier, the base-emitter current causes a corresponding collector-emitter current, in the ratio of hFe (beta gain) or collector resistance over emitter resistance, which ever is less. Since this ratio is usually greater than one, the differential collector current is greater than the differential base current. This results in amplification of the base signal. As you increase the base-emitter current, the collector-emitter current also increases. This results in the collector being pulled towards the emitter, with the result that the differential collector voltage decreases. This results in inversion of the base signal.
How differential protection work in a transformer?
Power flowing into a transformer must match the power flowing out (minus losses which are minimal). If this is not the case, there's something wrong. Differential protection monitors current only; Current flowing into one side of the transformer will be equal to current flowing out the other side scaled by the turns ratio of the transformer. Since the turns ratio is equivalent to the voltage ratio, this is easily set.
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.
About bus bar protection ques and ans?
Protection of busbars is mainly done using differential relays. These relays sense current flowing into the bus and current flowing out of the bus. If current in != current flowing out, the relay assumes there is a fault on the bus and trips breakers to isolate the bus.
What is defrential protection relay?
I am going to assume that you are asking about a differential relay. It is basically just that- it compare two different sources and will trip at a set value value of the difference. These can be directional as well. A couple of examples are transformer protective relays and bus differential. A transformer relay will measure the amount of current coming into the transformer and the amount of current going out. If there is a disparity due to an internal fault the relay will trip the supply source and deenergize the transformer. Same for the Bus differential.
