Power Generation: How It Works

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Electricity is the Steady flow of electrons Through a conductor such as copper wires and is used for heating and lighting and to provide power for machines.

Here is a simple Explanation:

Imagine that you have water in an overhead tank. The tap is shut. When the tap opens, water pours. This is because there is a “potential difference” between the tank and the tap outlet that causes the water to flow. Then replace the tank with power generating station, tap with a switch, and water with a current that powers your equipment. Makes sense?

Electricity is not your typical market product. It is consumed almost immediately it is produced and should be available for use as soon as you flick a switch or turn on a socket.

Electrical power is divided into 3 sectors: generation, transmission, and distribution.

We will try to explain how these 3 sectors combine to bring this ‘light’ into our houses.

GENERATION

Around 1800, Michael Faraday, a British Physicist, and chemist discovered Electromagnetic Induction (EMF) When he performed an experiment consisting of moving a magnet through the wire, thus creating Electricity.

You could try it at home: get a wire, wind it and pass a permanent magnet through it. Voila! You have electricity. The problem is, the magnet needs to keep moving to vary the magnetic field to keep generating electricity and the amount of electricity generated isn’t much.

To generate larger amounts of electricity, we need larger magnetic fields and bigger coils. This is basically how electricity generation works.

To generate electricity for a nation, we need bigger generators. Bigger generators can’t be pull-to-start, but still, need help to rotate the magnetic field. For this we need turbines. These turbines have blades that require a force to push them to rotate.

The force to turn the turbines could come from:

  • falling or flowing water (as in hydro stations),
  • wind speed (as in wind farms) or
  • the impact of hot steam and gases (as in thermal stations).

Generation companies in Nigeria are now referred to as GenCos. Examples of power stations in Nigeria are Kainji hydropower station, Egbin thermal station, and Afam thermal station.

Power plants are usually sited far from residential areas because of highly combustible fuels and pollutants like gaseous emissions and noise.

The world is seeking to generate power from renewable energy sources to combat pollution and diminishing reserves of crude oil. How then does the generated electricity reach the consumers?

Transmission.

Transmission is the process of evacuating power from the generating stations.

Going back to our overhead tank analogy, this is like the pipe that carries the water from the tank to the tap. The Transmission Company of Nigeria (TCN) is responsible for the transmission network in Nigeria. You may have seen tall towers like those in the figure above. They are called transmission towers and are used for distant power transmission. In addition to the support they provide for the wires carrying electricity, they also help to prevent them from excessive sagging.

Current is responsible for the heat generated in electric wires. The simple equation below shows that for the same amount of transmitted power, increasing the voltage will reduce the current.

This is why voltages are stepped up from the generation station using transformers, prior to transmission. The transmission voltages used in Nigeria are 330kV, 132kV, and 33kV. Standard values for transmission enable us to create an interconnecting network of transmission lines known as the grid. So any generating station can generate, step up to any of these voltages, and readily connect to this grid.

When the electricity reaches the transmission station, it is stepped down to a voltage of 11 or 33kV. This voltage is still too high for most of our home appliances. If you look at the nameplates on your appliances you’ll realize that most of them need a maximum of just 240V! How then do we convert 11/33kV to 240V?

DISTRIBUTION

This brings us to the need for distribution.

Distribution companies in Nigeria are now referred to as DisCos. Distribution transformers help step down voltage from 11/33kV to 415V. There are currently 11 DISCOS in Nigeria

You’ll notice that there are 3 wires on the distribution pole before they enter the transformer but they become 4 when they come out of the transformer and into your homes. This is because electricity is generated in a 3-phase pattern. The 4th line is the neutral line, which also goes into the ground or earth to prevent your home appliances from shocking you.

The most household equipment uses a single phase of electricity. Hence, one of the 3 phases on the distribution pole and the neutral line are used to supply residential buildings. This supply is 230 – 240V.

 

 

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