## Selection of Distance Relay

Selection of Distance Relay: The factors to be considered for the Selection of Distance Relay scheme can be enumerated as follows: Speed of operation. Measuring relay characteristics. Fault coverage. Economic considerations. 1. Speed of Operation:…

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## Current and Voltage Connection in Distance Relay

Current and Voltage Connection in Distance Relay: It is essential for the distance relay to measure the same distance between the fault and the relay under any type of fault condition. It is possible to…

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## Power Swings in Power System Protection

Power Swings in Power System Protection: The impedance measured or seen by a distance relay during normal load is shown in Fig. (5.29). Normally this would be outside the tripping zone of the distance relay,…

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## Distance Protection by Reactance Relays

Distance Protection by Reactance Relays: Like impedance relays, Distance Protection by Reactance Relays are also amplitude comparators and thus require an additional directional unit. Although the performance of reactance relays on single-fed systems is not…

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## Distance Protection Impedance Relay

Distance Protection Impedance Relay: Distance Protection Impedance Relay - It has already been pointed out that the impedance is directly proportional to the length of the line, and hence an impedance relay which measures impedance…

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## Scheme of Distance Protection

Scheme of Distance Protection: In developing an overall Scheme of Distance Protection, it is necessary to provide a number of relays to obtain the required discrimination. Modern practice is to adopt definite distance method of…

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## Reach of Distance Relay

Reach of Distance Relay: A distance relay is set to operate up to a particular value of impedance; for an impedance greater than this set value the relay should not operate. This impedance, or the…

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## Fault Resistance Calculation

Fault Resistance Calculation: Fault Resistance Calculation consists of two components, the resistance of the are and the resistance of earth. The second component is present only when it involves an earth-fault. In such a case…

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## Time Grading of Distance Relay

Time Grading of Distance Relay: Two methods of Time Grading of Distance Relay are shown in Fig. (5.18). First Method is the distance time method at (a) has the operating time increasing steadily with increasing…