Molded Case Circuit Breakers or MCCB circuit breakers are black plastic–cased automatic switches. They are designed to primarily protect insulating materials from overheating. Molded case circuit breakers (MCCB) are by far the most commonly used breakers in residential, commercial, and industrial facilities. When an MCCB has opened (or “tripped”) to protect the circuit, it can […]
Most insulations fail during one of the following events: Switching overvoltage due to the inductive and capacitive energy of the system overshooting the system voltage that can be as high as 2 × rated voltage. This is analogous to overpressure due to water hammer when a water pipe is suddenly shut off (switched-off). Lightning overvoltage
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The fuse provides protection by melting away a thin metal link in the faulted circuit. The metal link may be of silver, copper, or nickel, silver being more common for long-term performance stability. The fuse body is generally filled with a sand-type filler (Figure 1) to suppress sparks when the fuse link melts and interrupts the
The relay operation is a function of the input quantities, such as current, voltage, impedance, and/or phase angle. The relay can be made to respond to either a single quantity or a combination of two or all input quantities. When the relay is operated by a single quantity, its response is strictly a function of
A current limiting reactor is a coil which has a large inductive reactance in comparison with its ohmic resistance. It consists of a few turns of heavy copper strip, sometimes cast directly in concrete so that it can withstand large stress developed by the fault currents. Generally, the reactance of the power system under fault
The most common schemes employed for the protection of a three-phase generator stator windings from earth faults phase-to-phase faults make use of circulating current principle. In these protection schemes, currents at the two ends of the protected section are compared. Under normal conditions, these currents are equal became different on the occurrence of a fault in
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Hi friends, in this article, I am going to discuss the lightning arrester types and lightning arrester working principle. You will find this article very interesting and informative, I hope so. The lightning arresters are used to protect the power system from high voltage surges. An arrester does not absorb lightning or stop lightning. It