Tag: Power systems
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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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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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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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Main Types of Earthing Systems
Introduction The process of connecting the metallic frame i.e. non-current part of electrical equipment or some electrical part of the system such as the neutral point of the secondary side of the distribution transformers or the star point in a star connected system to the earth is called grounding or earthing. The potential of the…
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Common Causes of Failures of Power Transformers
As with most of electrical equipment, the key causes of failure of power transformers are either due to electrical failure or mechanical failure. These failures don’t occur that often as compared with other failures in other electrical equipment like switchgear. Common failures of power transformers and their causes are discussed in the following sections. Typical…
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Three-Phase Diode Bridge Rectifier: Function & Operation
In many high-powered applications, three-phase voltages need to be rectified to give rise to a single DC supply; such rectification can be accomplished using an extension of the bridge rectifier such as the three-phase diode bridge rectifier. Let’s consider the balanced three-phase circuit shown in Figure 1.0 below; the three-phase wye-connected source is connected to…
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Testing Power and Distribution Transformers
The typical practice for testing power and distribution transformers is to carry out a comprehensive set of tests at the manufacturer’s works. The number and nature of the tests depend on whether the transformer is the first of a new design or not, additionally a few relatively simple tests are done after installation at site…
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Major Technologies for Smart Grid Implementation
Smart grid can enhance legacy electric systems (i.e. the traditional electricity infrastructure) by improving reliability and security; additional smart grid can offer economic benefits and cost savings, environmental improvement, and so forth. Generally smart grid represents the integration of digital technologies, sensors and other information and communication technologies to enable more efficient and reliable electricity…