Technical Articles

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Distance Relays

Distance relay applications Distance relays respond to the voltage and current, i.e., the impedance, at the relay location. The impedance per mile is fairly constant so these relays respond to the distance between the… Read more

Nov 12, 2010 | Edvard

Distance relays

Gas-Insulated Substations – GIS

Superior Dielectric Gas A gas-insulated substation (GIS) uses a superior dielectric gas, SF6, at moderate pressure for phase-tophase and phase-to-ground insulation. The high voltage conductors, circuit breaker interrupters, switches, current transformers, and voltage transformers… Read more

Nov 10, 2010 | Edvard

Gas-Insulated Substations - GIS

Emergency lights

Many buildings must have some form of emergency lighting to come on if the electric supply to the ordinary lights fails. BS 5266: Emergency lighting, BS EN 1838, BS 5266–7: Lighting applications. Emergency lighting are the codes of practice to which to refer. One of the possible causes of failure is a breakdown in the supply authority’s service…

Nov 10, 2010 | Edvard

Emergency lights

Oil-Filled, Inert-Gas System

Inert-gas system // A positive seal of the transformer oil may be provided by an inert-gas system. Here, the tank is slightly pressurized by an inert gas such as nitrogen. The main tank gas… Read more

Nov 08, 2010 | Edvard

Oil transformer

What is the cost of electricity?

Electrification // Electrification in the early 20th century dramatically improved productivity and increased the well-being of the industrialized world. No longer a luxury – now a necessity – electricity powers the machinery, the computers,… Read more

Nov 02, 2010 | Edvard

Cost Of Electricity

Short-Circuit Electrical Currents

Introduction to short-circuit A short circuit is one of the major incidents affecting electrical systems. The consequences are often serious, if not dramatic: Although short circuits are less and less likely to occur in… Read more

Oct 28, 2010 | Edvard

Short-circuit current diagram

Power System Stability

Basic Concepts Power system stability is the ability of the system, for a given initial operating condition, to regain a normal state of equilibrium after being subjected to a disturbance. Stability is a condition… Read more

Oct 23, 2010 | Edvard


Types of Underground Lines

Methods of installing underground lines There are two methods of installing underground lines. In the first method, underground raceway systems (ducts) are installed below grade and then cable is pulled through them. Ducts may… Read more

Oct 22, 2010 | Edvard

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