Buchholz Relay

Definition: The Buchholz relay protects the transformer from internal faults. It is the gas actuated relay. The Buchholz relay is placed between the main tank and the conservator. Such type of relay is used in the transformer having the rating higher than 500KVA. It is not used in small transformer because of economic consideration. Working …

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High Voltage HRC Fuse

The HRC fuse element carries the short circuit or faults current for the specific interval of time. And if the fault removes in that specific period then the fuse element remains safe and it does not melt or breaks. The fuses element is kept inside the airtight container. The HRC fuse has inverse time characteristic, i.e., if …

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Low Voltage Fuses

Fuse is a current interrupting device which breaks or opens the circuit by fusing the element when the current in the circuit exceeds a certain value. Fuses are mainly categorised into two types, i.e., High voltage fuses and Low voltage fuses. Low voltage fuses can further divide into two types, namely semi-enclosed or rewirable type …

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Fuse Wire Materials

The material used for fuse elements must be of low melting point, low ohmic loss, high conductivity (or low resistivity), low cost and free from detraction. The material used for making fuse element has a low melting point such as tin, lead, or zinc. A low melting point is, however, available with a high specific …

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Electrical Fuse

The fuse is a device used in an electrical circuit for protecting electrical devices against overloads and short circuit. It is the simplest and cheapest devices used for interrupting an electrical circuit under short circuit or excessive overload current magnitudes. It is used for overload or short circuit protection in high voltage up to 66 …

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Restriking Transient Voltage

When the current across the contact of the circuit breaker is zero, a high-frequency transient voltage develops in the whole breaker contact and is produced by the sudden distribution of energy between the electric and magnetic field. This transient voltage is called restriking voltage. The voltage appears across the breaker contacts at the moment of …

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Testing of Circuit Breaker

Testing of circuit breakers is more difficult as compared to other electrical equipment like transformer or machine because the short circuit current is very large. Testing of the transformer is mainly divided into two groups, type tests, and routine tests. Type Tests of Circuit Breaker Type tests are conducted for the purpose of proving the …

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Air Break Circuit Breaker

In air break circuit breaker the arc is initiated and extinguish in substantially static air in which the arc moves. Such breakers are used for low voltages, generally up to 15KV and rupturing capacities of 500MVA. Air circuit breaker has several advantages over the oil, as an arc quenching medium. These are Elimination of risk …

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Air Blast Circuit Breaker

Air blast circuit breaker used compressed air or gas as the arc interrupting medium. In the air blast, circuit breaker compressed air is stored in a tank and released through a nozzle to produce a high-velocity jet; this is used to extinguish the arc. Air blast circuit breakers are used for indoor services in the …

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HVDC Circuit Breaker

The HVDC circuit breaker is a switching device that interrupts the flow of abnormal direct current in the circuit. When the fault occurs in the system, the mechanical contacts of the circuit breaker are pulled apart and thus their circuit is open. In HVDC circuit breaker, circuit breaking is difficult because the current flow through …

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