Tuesday, January 26, 2010

Pole Mounted Sub-Stations

I was going around town, with a colleague, we came across a structure which by the roadside that my friend was quick to refer to as transformer. I quickly corrected him that its actual name is not a transformer as many might call it, rather it’s called a Pole Mounted Sub-Station.

A Pole Mounted Sub-station is a large, free standing, outdoor electrical equipment that is mostly located in residential places. Its main purpose is to step-down the lethal 11kV to 415/240V for light, commercial and residential loads (consumers)...

Thursday, January 21, 2010

Electric Power Supply Systems

Supply Systems

The convergence of electric power from a Power Station to consumer’s premises is known as Electric Supply Systems.

This post illustrates the basic movement of power from the alternators at the generating station to your home/premises. I have omitted the complicated processes because its meant to give Non-Engineers a glimpse of how power is transmitted.

Generating Station

3-Phase alternators in parallel - The common generation is normally 11kV or 33kV (For advanced countries).

For economical reasons power is stepped up to 132kV or even more depending upon length of transmission lines and amount of power to be transmitted. It is stepped up to 132kV with the help of 3-phase transformers.

The transmission of power at high voltages has several advantages including saving conductor material and high transmission efficiency...

Monday, January 18, 2010

What Is 3-Phase Power?

When a conductor is rotated to cut magnetic fields, some electromotive force is induced according to Faradays Law. This voltage/emf is always in opposition to the main field according Lenz’s Law

E = -Ndø/dt

The voltage induced by a single winding is known as single phase winding, when rotated in a uniform magnetic field is known as single phase voltage.

A 3-Phase generator has 3 separate but identical conductors that are 120 Electrical degrees from one another. When the conductors are rotated in a uniform magnetic field, the result is 3 independent supplies of equal voltages which are displaced from each other.

A 3-Phase supply is carried by 3 conductors known as lines which are colored Red, Yellow & Blue. The currents in these cables are known as Line Currents and the Voltages are known as Line Voltages. The 4th conductor, known as Neutral is often used with the 3phase supply when the load is unbalanced.

Thursday, January 7, 2010

Safety With Electricity

Electricity can be interesting to work with but i got to emphasize that always put on all necessary safety wear when handling electricity.

Trust me, I went through an electric shock incident and it wasn't a walk in the park...