Primary & Backup Protection

Primary Protection The main protection or primary protection is the first line protection which provides quick-acting and selective clearing of a fault within the boundary of the circuit section or element it protects. The main protection is provided in each section of an electrical installation. Backup Protection The backup protection provides the back up to…

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Summation Current Transformer

Definition: The transformer which is used for converting the three-phase quantities into the single phase quantity is known as the summation transformer. This transformer is mainly employed for the unbalanced condition in the system and due to fault condition so that the relay operates properly. The connection of the summation current transformer is shown in…

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Ungrounded System

Definition: The system without neutral grounding is known as the ungrounded system, or in other words, in the ungrounded system, none of their conductors is connected to the ground. The main feature of the ungrounded system is its ability to remove the earth faults without interruption. But the self-cleaning process of the ungrounded system become…

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Earth Resistance

Definition: The resistance offered by the earth electrode to the flow of current into the ground is known as the earth resistance or resistance to earth. The earth resistance mainly implies the resistance between the electrode and the point of zero potential. Numerically, it is equal to the ratio of the potential of the earth…

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Types of Fuses

The fuse is the current interrupting devices which break or open the circuit by fusing the element and thus remove the faulty device from the main supply circuit. The fuses are mainly classified into two types, depends on the input supply voltages they are the AC fuses and the DC fuses. The different types of…

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Types of Circuit Breaker

There are several methods of classification of circuit breakers. The most general way of the rating of a circuit breaker is by the arc extinction medium. The arc extinction can easily be done by using the different medium like air, insulator, gas, vacuum, dielectric, etc. By the arc extinction medium, the circuit breaker is categorised into…

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Valve Type Lightning Arrester

Definition: The lightning arrester which consists the single or multi-gaps connected in series with the current controlling element, such type of arrester is known as the lightning arrester. The gap between the electrodes intercepts the flow of current through the arrester except when the voltage across the gap raises beyond the critical gap flashover. The…

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Relay

Definition: The relay is the device that open or closes the contacts to cause the operation of the other electric control. It detects the intolerable or undesirable condition with an assigned area and gives the commands to the circuit breaker to disconnect the affected area. Thus protects the system from damage. Working Principle of Relay…

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Percentage Differential Relay

Definition: The percentage differential relay is defined as the relay that operates on the phase difference of two or more similar electrical quantities. It is the advanced form of differential protection relay. The only difference between them is the restraining coil. The percentage differential relay consists restraining coil for overcoming the trouble arising out of differences in…

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Electromagnetic Relay

Definition: Electromagnetic relays are those relay which operates on the principle of electromagnetic attraction. It is a type of a magnetic switch which uses the magnet for creating a magnetic field. The magnetic field then uses for opening and closing the switch and for performing the mechanical operation. Types of an Electromagnetic Relay By their working…

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