# Application of Relay

## Application of Relay:

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, Application of Relay …

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 conditions or even under faults outside …

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 …

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 directional feature is incorporated in the …

Distance Relays Types : In applying relays to a transmission system it is necessary to state the relay characteristic in the same terms that the system conditions are stated. This is especially true of …

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, …

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 reducing …

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 …

Single Phase Directional Relay : Single Phase Directional Relay – The general Eq. (4.8) suggests that for directional control the individual torques, viz. K |A|2 and K′ |B|2 should be eliminated. Considering a voltage current directional relay the general Eq. …

Time Current Relay Application : Time Current Relay Application – Overcurrent and earth fault protective gear can be made discriminative by grading the operating times of successive devices. The pickup currents are adjusted in such a way …