Transformer Protection Types: Nature of Transformer Faults: Power transformers, being static, totally enclosed and oil immersed develop faults only rarely but the consequences of even a rare fault may be…
Pilot Wire Protection Relay: In this case the auxiliary Pilot Wire Protection Relay are provided to carry the information signals from one end to the other. Protective systems requiring the…
Directional Earth Fault Relay: In the case of Directional Earth Fault Relay the angular relationship of residual current and residual voltage is independent of the faulted phase and is governed…
Overcurrent Earth Fault Protection: Overcurrent Earth Fault Protection - Earth-fault protection can be provided with normal overcurrent relays, if the minimum earth-fault current is sufficient in magnitude. The magnitude of…
Differential Relay Application: The principle of operation depends on a simple circulating current principle where the difference of the currents of the two CTs flows through the relay under normal…
Directional Relays: Selective protection cannot be achieved with time graded overcurrent protection systems in ring or loop systems as well as in radial circuits with two end power supply. A…
Instantaneous Overcurrent Relays: If the relay operates instantly without any intentional time delay, this characteristic can generally be satisfied by a relay of the non-polarized attracted armature type. This relay…
General Equation for Electromagnetic Relay: It has already been shown that when not more than two quantities are involved, the equation for the characteristic of the relay at the threshold…