Almost everyone imagines the purpose of hydroelectric power plants, but only a few reliably understand the principle of operation of hydroelectric power stations. The main mystery for people is how all this huge dam without any fuel generates electrical energy. We’ll talk about this.
What is a hydroelectric power station?
A hydroelectric power station is a complex complex consisting of various structures and special equipment. Hydroelectric power plants are being built on rivers, where there is a constant influx of water to fill the dam and reservoir. Such structures (dams) created during the construction of a hydroelectric power station are necessary for the concentration of a constant flow of water, which is converted into electrical energy using special equipment for hydroelectric power plants.
It should be noted that the choice of a place for construction plays an important role in terms of the efficiency of hydropower plants. Two conditions are necessary: guaranteed inexhaustible water supply and a high angle of the river.
The principle of operation of hydroelectric power stations
The operation of a hydroelectric power station is quite simple. The erected hydraulic structures provide a stable pressure of water that enters the turbine blades. The pressure drives the turbine, as a result of which it rotates the generators. The latter generate electricity, which is then delivered to the consumer via high-voltage transmission lines.
The main difficulty of such a structure is to ensure a constant pressure of water, which is achieved by erecting a dam. Thanks to it, a large volume of water is concentrated in one place. In some cases, a natural flow of water is used, and sometimes a dam and a derivation (natural flow) are used together.
In the building itself there is equipment for hydroelectric power stations, the main task of which is to convert the mechanical energy of the movement of water into electrical energy. This task is assigned to the generator. Also used are additional equipment for monitoring the operation of the station, distribution devices and transformer stations.
The picture below shows a schematic diagram of a hydropower plant.
As you can see, the water stream rotates the generator’s turbine, it generates energy, supplies it to the transformer for conversion, after which it is transported through the power transmission line to the supplier.
Power
There are various hydroelectric power plants that can be divided according to the generated capacity:
- Very powerful - with a generation of more than 25 MW.
- Medium - with generation up to 25 MW.
- Small - with a generation of up to 5 MW.
The power of a hydropower plant depends primarily on the flow of water and the efficiency of the generator itself, which is used on it. But even the most efficient installation will not be able to produce large amounts of electricity with low water pressure. It is also worth considering that the capacity of a hydroelectric power station is not constant. For natural reasons , the water level in the dam can increase or decrease. All this affects the volume of electricity produced.
Dam role
The most complex, large and generally the main element of any hydroelectric power station is a dam. It is impossible to understand what a hydropower plant is without understanding the essence of the dam. They are huge bridges that hold the water flow. Depending on the design, they may differ: there are gravity, arched and other structures, but their goal is always the same - to retain a large volume of water. It is thanks to the dam that it is possible to concentrate a stable and powerful flow of water, directing it to the blades of the turbine that rotates the generator. He, in turn, produces electrical energy.
Technology
As we already know, the principle of operation of a hydropower plant is based on the use of the mechanical energy of falling water, which is subsequently converted into electrical energy using a turbine and generator. The turbines themselves can be installed either in the dam or near it. In some cases, a pipeline is used through which water below the level of the dam passes under high pressure.
There are several indicators of the power of any hydroelectric power station: water flow and hydrostatic pressure. The last indicator is determined by the height difference between the starting and ending points of free fall of water. When creating a plant project, the whole structure is based on one of these indicators.
The electricity production technologies known today allow obtaining high efficiency when converting mechanical energy into electrical energy. Sometimes it is several times higher than that of thermal power plants. Such high efficiency is achieved due to the equipment used at the hydroelectric power station. It is reliable and relatively easy to use. In addition, due to the lack of fuel and the release of large amounts of thermal energy, the service life of such equipment is quite large. Damage here is extremely rare. It is believed that the minimum service life of generator sets and structures in general is about 50 years. Although in fact, even today, hydropower plants that were built in the thirties of the last century are quite successfully operating.
Hydroelectric Power Plants of Russia
Today in Russia there are about 100 hydroelectric power stations. Of course, their capacity is different, and most of them are stations with installed capacity of up to 10 MW. There are also stations such as Pirogovskaya or Akulovskaya, which were commissioned back in 1937, and their capacity is only 0.28 MW.
The largest are the Sayano-Shushenskaya and Krasnoyarsk hydroelectric power stations with a capacity of 6400 and 6000 MW, respectively. They are followed by stations:
- Bratsk (4,500 MW).
- Ust-Ilim Hydroelectric Power Station (3840).
- Bochuganskaya (2997 MW).
- Volzhskaya (2660 MW).
- Zhigulevskaya (2450 MW).
Despite the huge number of such stations, they generate only 47,700 MW, which is equal to 20% of the total volume of all energy produced in Russia.
Finally
Now you understand the principle of operation of hydroelectric power plants that convert the mechanical energy of a water stream into electrical energy . Despite the rather simple idea of generating energy, a set of equipment and new technologies make such structures difficult. However, compared with nuclear power plants, they are indeed primitive.