HYDRO-ELECTRIC POWER
The principle here is called hydro-power energy or hydroelectricity, hydro means water, and thus, hydro-power energy is power gotten from water.
You must have been wondering how water becomes a strong tool in the generation of electricity, you might also be wondering how the whole process operates most especially that of our own Kainji dam also known as Niger dam, how on earth would a dam (a dam is a body of non-flowing water) be the basis of power generation in Nigeria, this article explains in lay man terms the simple principle behind power generation from water.
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Now let’s roll, the process of hydropower energy in this case all starts at the dam, as i said earlier, a dam is a body of water that is not flowing, in other words it is a barrier constructed across a stream to impound water, thus, a dam can be said to be synonymous to a reservoir of water.
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Water in the dam is allowed to flow through pipes called penstock in a vertical plane, it is to be noted that there is a need for a difference in height between the dam and the other components of the plant. Each penstock has its own hitch gate at the top to stop water flow for maintenance or during emergency. i.e. to control water flow.
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At the end of the penstock is the scroll case , which is designed to create a consistent pressure of water entering the turbine from all sides. Inside the scroll case is a set of veins known as the wicket gate.
The wicket gates (Pictures 4 & 5) are controlled by a governor system which closes and opens them in response to the condition at the national grid, this means that a higher load on the system opens the wicket gate and a lower load on the system gradually shuts the wicket gate.
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The turbine blades transmits the rotational motion to a shaft known as the runner which in turn transmits to the generator.
The generator at this point is not the same as the domestic generator, though they both work with the same principle, the principle of electromagnetism, just that the rotational motion in the domestic generator is gotten from the piston effect which is sourced from burning fossil fuel i.e. petrol , contrarily, the rotational motion in this plant is sourced from water which drives the turbine to turn kinetic energy to mechanical energy.
The generator then uses the principle of electromagnetic induction to turn the mechanical energy developed by the turbine to a three phase alternating current which is Electrical energy; this connects to the national grid and then subsequently gets transmitted and distributed via transmission and distribution lines respectively, and that’s how you get power at your homes and offices for both domestic and industrial uses.
Summarily, the process starts at the dam which serves as a reservoir for water, water is allowed to move vertically downwards through what is known as a penstock, the penstock channels the water directly to the blade of the turbine, a turbine blade is just like the fan blades we use at home, but constructed with the sole aim to turn kinetic energy to mechanical energy (via rotation). The mechanical energy generated at the turbine is transmitted to the generator through a shaft known as the runner; when current is passed through magnets, the magnets are said to be electromagnetic, an AVR (automated voltage regulator is connected to the exciter to supply voltage to make the magnets electromagnetic. The generator here works with the same principle of electromagnetism whereby a conductor cuts across an electromagnetic field to create induced electromotive force at the end of each full revolution.
It is also worthy to note that the three color codes used in everyday electrical connections also got its root from this concept: the stator is made up of three distinct conductors with different properties and as such the current generated at every stage of the revolution differs.
Thanks for reading
Very nice introduction about hydro power.