Application of Relay

Directional Overcurrent Relays in Power Systems

Directional Overcurrent Relays in Power Systems: Directional Overcurrent Relays in Power Systems – Relay connections must be made so that the currents and voltages applied to the relay during the various fault conditions which may arise on the protected circuit section afford the relay a positive and sufficiently large operating torque. To achieve this for …

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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 saturation of the magnetic circuit. So by varying the point of saturation different Overcurrent Relay Characteristics are obtained; these are: …

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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 conditions, when plotted on complex planes is a circle. The General Equation for Electromagnetic Relay can be represented in a …

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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 S1 and S2 be the two input signals such that when the phase relationship or magnitude relationship obeys predetermined threshold conditions, tripping is initiated. The input signals are …

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