Differential Relay: Most of the relays discussed so far relied on excess of current for their operation. Such relays are less sensitive because they cannot make correct distinction between heavy load conditions and minor fault…

Definite Distance Type Impedance Relay: Fig. 21.21 shows the schematic arrangement of a Definite Distance Type Impedance Relay. It consists of a pivoted beam F and two electromagnets energized respectively by a current and voltage…

Distance Relays or Impedance Relays: The operation of the relays discussed so far depended upon the magnitude of current or power in the protected circuit. However, there is another group of relays in which the…

Induction Type Directional Overcurrent Relay: The directional power relay is unsuitable for use as a directional protective relay under short-circuit conditions. When a short-circuit occurs, the system voltage falls to a low value and there…

Induction Type Directional Power Relay: This Induction Type Directional Power Relay operates when power in the circuit flows in a specific direction Unlike a non-directional overcurrent relay, a directional power relay is so designed that…

Induction Type Overcurrent Relay(Non-Directional): This Induction Type Overcurrent Relay works on the induction principle and initiates corrective measures when current in the circuit exceeds the predetermined value. The actuating source is a current in the…

Relay Timing Circuit: An important characteristic of a relay is its time of operation. By the Relay Timing Circuit of operation is meant length of the time from the instant when the actuating element is…

Electromagnetic Attraction Relay - Working Principle and its types: Electromagnetic attraction relay operate by virtue of an armature being attracted to the poles of an electromagnet or a plunger being drawn into a solenoid. Such…