Category: Power Systems
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The Principles of Power System Protection
The Function and Principles of Power System Protection The objective of power system protection is to detect faults or abnormal operating conditions and initiate corrective action. Principles of Power System Protection There are different principles used in accomplishing power system protection, we have discussed them in the following sections: Discrimination by Time In simple radial…
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Overvoltage Protection Techniques & Equipment
Overvoltage Protection – Objective, Methods & Equipment The purpose of the protective equipment in a power system is to isolate the faulty section from the healthy system by initiating tripping for appropriate circuit breakers. This whole process must be carried out with minimum of delay and disturbance. Overvoltage, switching and other phenomena like lightning produce…
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What is Corona Discharge in Power Transmission Conductors?
Corona and its Effects in Power Transmission Systems What is Corona? Corona is the term used to describe the violet glow or ‘brush’ discharge around conductors when the air is stressed beyond the ionization point without flashover developing. When an alternating potential difference is applied across two conductors whose spacing is large as compared to…
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Air Circuit Breakers: Features, Operation & Applications
Air Circuit Breaker Features & Operation An air circuit breaker employs atmospheric air as its interrupting medium. The arc is drawn between its contacts and extended via arc runners on to an arc chute where it is presented with a large cooling surface of arc splitter plates. These break the arc into a number of…
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Residential Electrical Wiring: Key Safety Considerations
Residential Electrical Wiring Overview A residential electric power service typically consists of a three wire ac system supplied by the local power utility company. A distribution transformer with a primary and two secondaries formed with a center tap on the secondary side is shown below: The distribution transformer is located on the utility pole, from…
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Electric Wiring Testing & Inspection Instruments Requirements
In order to carry out the verification process proficiently, the person conducting the inspection and test must be in possession of suitable test instruments. In this article, we look at some of the key requirements for electric wiring testing and inspection instruments. The commonly used instruments for electric wiring testing and inspection include: Nowadays we…
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Protective Relays: Function, Features & Operation
A protective relay is basically an electrical device that detects a fault in a power system and initiates the operation of the circuit breaker to isolate the defective section or component from the rest of the system. In other words, the prime function of protective relays is the timely and discriminative clearance of system faults.…
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SF6 Circuit Breakers: Features, Operation & Applications
Introduction Many modern designs of circuit breakers for use at transmission voltages utilize sulphur hexafluoride (SF6) gas both as an arc-interrupting/arc-quenching and a dielectric medium. At distribution voltages SF6 designs of circuit breakers are also used, however vacuum and bulk-oil circuit breakers still find a wide use as alternatives. The SF6 is an electron-negative gas…
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5 Causes of High-Voltage Switchgear Failures
Switchgear is basically equipment used switch ON or OFF generators, transmission lines, distributors and other equipment under both normal and abnormal conditions. Switchgear consists of switching and protecting devices such as switches, fuses, circuit breakers, relays, and so forth. In other words switchgear can be defined as equipment used for switching, controlling and protecting the…