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…
Harmonic Restraint Differential Relay for Transformer Protection: The operation of the relays because of magnetising inrush current can be avoided by using kick fuses across the relay coils or using…
Directional Static Overcurrent Relay: For obvious reasons of obtaining selectivity overcurrent relays are made directional. Directional static overcurrent relay senses direction of power flow by means of phase angle between…
Classification of Relays: The protective relay may be defined as an electrical device interposed between the main circuit and the circuit breaker in such a manner that any abnormality in…
Protective Relays Interview Questions and Answers: 1. What is a protective relay ? Ans. Protective relay is an electrical device designed to initiate isolation of a part of an electrical…
Application of Relay Articles: Comparator Equation in Power System Protection: Taking a very general case to cover the complete range of conventional relay characteristics, let S1 and S2 be the…
Overcurrent Protection Relay in Power System: The technique of Overcurrent Protection Relay in Power System is still widely used as a means of detecting faults on distribution system and on…
Basic Elements of Static Relay: The basic elements of a static relay are namely, Input Element: Mixing circuits are needed to sum the input signals in a convenient form. Semiconductor…