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:…
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…
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,…
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…
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…
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…
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…
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…
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…
Principle of Distance Relaying: The Principle of Distance Relaying is governed by the ratio of voltage to current at the relay location and the operating time of the relay automatically increases with an increase of…
