## Instantaneous Overcurrent Relays

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 has a special advantage of…

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## Overcurrent Relay Characteristics

Overcurrent Relay Characteristics: The operating time of all Overcurrent Relay Characteristics tends to become asymptotic to a definite minimum value with increase in the value of current. This is inherent in electromagnetic relays due to…

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## General Equation for Electromagnetic 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 of operation under steady state…

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## Comparator Equation in Power System Protection

Comparator Equation in Power System Protection: Comparator Equation in Power System Protection - Taking a very general case to cover the complete range of conventional relay characteristics, let S1Â and S2 be the two input signals…

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## Relay Design and Construction

Relay Design and Construction: The Relay Design and Construction is normally divided into the following stages: Selection of the operating characteristics. Selection of proper construction. Design of the contact movement from the point of view…

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## Induction Relay Torque Equation

Induction Relay Torque Equation: In Induction Relay Torque Equation, Two magnetic fluxes Î¦1Â and Î¦2Â differing in time phase penetrate through a disc. These alternating fluxes induce emfs e1 and e2 in the disc which lag their…

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## Types of Electromagnetic Relays

Types of Electromagnetic Relays: There are two principal Types of Electromagnetic Relays: Attracted armature type; and Induction type. (a) Attracted Armature Type: This includes plunger, hinged armature, balanced beam and moving iron polarized relays. These…

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## Relay Classification in Power System Protection

Relay Classification in Power System Protection: There are various types of Relay Classification in Power System Protection. Normally the actuating quantity is an electrical signal, although sometimes the actuating quantity may be pressure or temperature.…

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## Components of Protection System

Components of Protection System: Some of the more commonly used Components of Protection System are Relays Circuit Breakers Tripping and Other Auxiliary Supplies Current Transformer (CT) Voltage Transformers (VT) Linear Coupler Relays: The main function…

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## Derivation of Single Phase Quantity from Three Phase System

Derivation of Single Phase Quantity from Three Phase System: It will be seen later that auxiliary channels or pilot wires are used to transmit information from one end of the line to the other end.…

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