How does a hydro generator work. Varieties of hydroelectric power stations and principles of operation of stations. Major accidents and incidents

A hydroelectric power plant is a complex of complex hydraulic structures and equipment. Its purpose is to convert the energy of the water flow into electrical energy. Hydropower is one of the so-called renewable energy sources, that is, it is practically inexhaustible.

The most important hydraulic structure is the dam. It retains water in the reservoir, creates the necessary pressure of water. The hydraulic turbine is the main engine in a hydroelectric power station. With its help, the energy of water moving under pressure is converted into mechanical energy rotation, which is then (thanks to an electric generator) converted into electrical energy. Hydraulic turbine, hydro generator, automatic monitoring and control devices - consoles are located in the engine room of the hydroelectric power station. Step-up transformers can be located both inside the building and in open areas. Switchgears are most often installed outdoors next to the power plant building.

In the Soviet Union, which has large hydropower resources (11,112% of the world's), extensive construction of hydroelectric power stations has been launched. According to the installed capacity of hydroelectric power. Only in the 30 post-war years, from 1950, the stations were divided into small - up to 1980, electricity generation up to 5 MW, medium - from 5 to 25 and large - hydroelectric power plants increased by more than 10 times. over 25 MW. There are 20 hydroelectric power stations in our country, each of which has an installed capacity of more than 500 MW. The largest of them are the Krasnoyarskaya (6000 MW) and Sayano-Shushenskaya (6400 MW) HPPs.

The construction of a hydroelectric power station is unthinkable without a comprehensive solution of many problems. It is necessary to meet the needs of not only energy, but also water transport, water supply, irrigation, and fisheries. These tasks are best met by the principle of cascading when not one, but a number of hydroelectric power stations located along the river are built on the river. This allows you to create on the river several successively located on different levels reservoirs, which means making fuller use of the river's runoff, its energy resources and maneuvering the capacity of individual hydroelectric power stations. Cascades of hydroelectric stations have been built on many rivers. In addition to the Volga, cascades were built on the Kama, Dnieper, Chirchik, Hrazdan, Irtysh, Rioni, Svir. The most powerful Angara-Yenisei cascade with the world's largest HPPs - Bratskaya, Krasnoyarskaya, Sayano-Shushenskaya and Boguchanskaya with a total capacity of about 17 GW and an annual output of 76 billion kWh of electricity.

There are several types of power plants that use the energy of the flow of water. In addition to hydroelectric power plants, pumped-storage power plants (PSPPs) and tidal power plants (TPPs) are also being built. At first glance, you can hardly notice the difference between a conventional hydroelectric power plant and a hydro-storage power plant. The same building where the main power equipment is located, the same power lines. There is no fundamental difference in the way electricity is produced. What are the features of HPS?

Unlike a hydroelectric power plant, a pumped-storage plant requires two reservoirs (and not one) with a capacity of several tens of millions of cubic meters. The level of one should be several tens of meters higher than the other. Both reservoirs are interconnected by pipelines. A PSP building is being built on the lower reservoir. In it, the so-called reversible hydraulic units - hydraulic turbines and electric generators are placed on the same shaft. They can work both as current generators and as electric water pumps. When energy consumption decreases, such as during the night hours, hydraulic turbines act as pumps, pumping water from the lower reservoir to the upper one. In this case, the generators work as electric motors that receive electrical energy from thermal and nuclear power plants. When the consumption of electricity increases, the HPP hydroelectric units switch to reverse rotation. Water falling from the upper reservoir to the lower one rotates hydraulic turbines, generators generate electrical energy. Thus, at night hours, the pumped storage power plant, as it were, accumulates electricity generated by other power plants, and gives it away during the day. Therefore, the pumped storage power plant usually serves, as the power engineers say, to cover the “peaks” of the load, that is, it provides energy when it is especially needed. More than 160 pumped storage power plants operate on the globe. In our country, the first pumped storage power plant was built near Kyiv. It has a low head, only 73 m, and a total capacity of 225 MW.

A larger pumped storage power plant in the Moscow region was put into operation, with a capacity of 1.2 GW, with a head of 100 m.

Usually pumped storage power plants are built on rivers. But, as it turned out, such power plants can be built on the shores of the seas and oceans. Only there they received a different name - tidal power plants (PES).

Twice a day at the same time, the ocean level either rises or falls. It is the gravitational forces of the Moon and the Sun that attract masses of water towards them. Away from the coast, fluctuations in the water level do not exceed 1 m, but near the coast they can reach 13 m, as, for example, in the Penzhinskaya Bay on the Sea of ​​Okhotsk.

If a bay or the mouth of a river is blocked by a dam, then at the moment of the greatest rise in water, hundreds of millions of cubic meters of water can be blocked in such an artificial reservoir. When the tide is low in the sea, a difference is created between the water levels in the reservoir and in the sea, sufficient for the rotation of the hydro turbines installed in the TPP buildings. If there is only one reservoir, the TPP can generate electricity continuously for 4-5 hours with interruptions, respectively, 1-2 hours four times a day (the water level in the reservoir changes so many times during high and low tides).

To eliminate uneven power generation, the station's reservoir is divided by a dam into 2-3 smaller ones. In one, they maintain the level of low tide, in the other - the level of high tide, the third serves as a backup.

Hydroelectric units are installed at the PPP, which are capable of operating with high efficiency both in generating (to produce electricity) and in pumping mode (pumping water from a reservoir with a low water level to a reservoir with a high level). In the pumping mode, the PES operates when excess electricity appears in the power system. In this case, the units pump up or pump out water from one reservoir to another.

In 1968, on the coast of the Barents Sea in Kislaya Guba, the first pilot TPP in our country was built. There are 2 hydraulic units with a capacity of 400 kW in the building of the power plant.

Ten years of experience in the operation of the first TPP made it possible to start drawing up projects for the Mezenskaya TPP on the White Sea, Penzhinskaya and Tugurskaya on the Sea of ​​Okhotsk.

Using the great forces of the tides of the World Ocean, even the ocean waves themselves, is an interesting problem. They are just starting to solve it. There is much to be studied, invented, designed.

The construction of large energy giants - whether it be a hydroelectric power station, a hydroelectric power station or a PES - is an exam for builders every time. Here the work of workers of the highest qualification and different specialties is combined - from masters concrete work to climbers.

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Almost everyone imagines the purpose of hydroelectric power plants, but only a few truly understand the principle of operation of hydroelectric power plants. The main mystery for people is how this whole huge dam generates electrical energy without any fuel. We'll talk about this.

What is a hydroelectric power station?

A hydroelectric power plant is a complex complex consisting of various structures and special equipment. Hydroelectric power plants are being built on rivers, where there is a constant flow of water to fill the dam and reservoir. Similar structures (dams) created during the construction of a hydroelectric power plant are necessary to concentrate 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 the HPP. Two conditions are necessary: ​​a guaranteed inexhaustible supply of water and a high angle

The principle of operation of the hydroelectric power station

The operation of a hydroelectric power plant is quite simple. The erected hydraulic structures provide a stable pressure of water that enters the turbine blades. The pressure sets the turbine in motion, as a result of which it rotates the generators. The latter generate electricity, which is then delivered to the consumer through high-voltage transmission lines.

The main difficulty of such a structure is to ensure a constant pressure of water, which is achieved by building a dam. Thanks to it, a large amount of water is concentrated in one place. In some cases, a natural flow of water is used, and sometimes a dam and derivation (natural flow) are used together.

The building itself houses equipment for hydroelectric power stations, the main task of which is to convert the mechanical energy of water movement into electrical energy. This task is assigned to the generator. Additional equipment is also used to control the operation of the station, distribution devices and transformer stations.

The picture below shows a schematic diagram of a hydroelectric power station.

As you can see, the flow of water rotates the turbine of the generator, which generates energy, supplies it to the transformer for conversion, after which it is transported through power lines to the supplier.

Power

There are different hydroelectric power plants, which can be divided according to the generated power:

1. Very powerful - with a production of more than 25 MW.
2. Medium - with generation up to 25 MW.
3. Small - with generation up to 5 MW.

Technology

As we already know, the principle of operation of a hydroelectric power station 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 head. The latter indicator is determined by the height difference between the start and end point of the free fall of water. When creating a station design, the entire design is based on one of these indicators.

Known today technologies for the production of electricity make it possible to obtain 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 emission a large number thermal energy, the service life of such equipment is quite large. Breakdowns are extremely rare here. It is believed that the minimum service life of generator sets and structures in general is about 50 years. Although in fact, even today, hydroelectric power stations that were built in the thirties of the last century are quite successfully functioning.

Hydroelectric power plants in Russia

Today, about 100 hydroelectric power stations operate in Russia. Of course, their capacity is different, and most of them are plants with an installed capacity of up to 10 MW. There are also such stations as Pirogovskaya or Akulovskaya, which were put into operation in 1937, and their capacity is only 0.28 MW.

The largest are the Sayano-Shushenskaya and Krasnoyarskaya HPPs with a capacity of 6,400 and 6,000 MW, respectively. Stations follow:

1. Bratskaya (4500 MW).
2. Ust-Ilimskaya HPP (3840).
3. Bochuganskaya (2997 MW).
4. Volzhskaya (2660 MW).
5. 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, which convert mechanical water into electrical water. Despite the rather simple idea of ​​obtaining energy, the complex of equipment and new technologies make such structures complex. However, compared to they are really primitive.

Features of HPPs The cost of electricity at Russian HPPs is more than two times lower than at thermal power plants; Hydroelectric generators can be turned on and off fairly quickly depending on energy consumption; Renewable energy source is used; Significantly less impact on the air than other types of power plants. The construction of hydroelectric power plants is usually more capital intensive; Often effective HPPs are more remote from consumers; Reservoirs often cover large areas; Dams often change the nature of the fish economy, as they block the path to spawning grounds for migratory fish, but often favor the increase in fish stocks in the reservoir itself and the implementation of fish farming.

Types of HPPs Hydroelectric power plants (HPPs): Dam hydroelectric power plants; Run-of-river hydroelectric power plants; Near-dam hydroelectric power stations; Derivative hydroelectric power plants; hydrostorage power plants; Tidal power plants; Wave power plants and on sea currents.

Run-of-river hydroelectric power plant (RusHPP) Run-of-river hydroelectric power plant (RusHPP) refers to damless hydroelectric power plants, which are located on flat high-water rivers, in narrow compressed valleys, on mountain rivers, as well as in fast currents of seas and oceans.

Hydrostorage power plants (PSPP) Hydrostorage power plants are used to equalize the daily inhomogeneity of the electrical load schedule. During low load hours, the PSPP, consuming electricity, pumps water from the downstream reservoir to the upstream one, and during hours of increased load in the power system, it uses the stored water to generate peak energy.

Tidal power plant (TPP) Tidal power plants use the energy of the tides. Tidal power plants are built on the shores of the seas, where the gravitational forces of the Moon and the Sun change the water level twice a day. Water level fluctuations near the coast can reach 13 meters.

Wave power plants Two main characteristics of waves are used to generate electricity: kinetic energy, and surface rolling energy. It is these factors that are trying to use in the construction of wave power plants. Scheme of operation of wave hydroelectric power plants

Principle of operation General principle work: HPPs convert the kinetic energy of falling water into the mechanical energy of the rotation of the turbine, and the turbine drives the electric machine current generator. The necessary pressure of water is formed through the construction of a dam, and as a result of the concentration of the river in a certain place, or by diversion by the natural flow of water. A chain of hydraulic structures provides the necessary pressure of water flowing to the blades of a hydraulic turbine, which drives generators that generate electricity. All power equipment is located directly in the building of the hydroelectric power station. Depending on the purpose, it has its own specific division. In the engine room there are hydraulic units (they convert the energy of the water flow into electrical energy). There are also all kinds of additional equipment, control and monitoring devices for the operation of hydroelectric power stations, a transformer station, switchgear and much more.

HPP capacity Hydroelectric stations are divided depending on the generated power: powerful ones generate from 25 MW to 250 MW and more; average up to 25 MW; small hydroelectric power plants up to 5 MW. The power of a hydroelectric power station directly depends on the pressure of the water, as well as on the efficiency of the generator used. Due to the fact that, according to natural laws, the water level is constantly changing, depending on the season, and also for a number of reasons, it is customary to take cyclic power as an expression for the power of a hydroelectric station. For example, there are annual, monthly, weekly or daily cycles of operation of a hydroelectric power station. Hydroelectric power plants are also divided depending on the maximum use of water pressure: high-pressure more than 60 m; medium pressure from 25 m; low-pressure from 3 to 25 m.

Types of turbines Depending on the pressure of the water, different types of turbines are used in hydroelectric power plants: For high-pressure bucket and radial-axial turbines with metal volute chambers. At medium-pressure hydroelectric power plants, rotary-blade and radial-axial turbines are installed, at low-pressure rotary-blade turbines in reinforced concrete chambers. The principle of operation of all types of turbines is similar. Turbines differ in some technical specifications, as well as iron or reinforced concrete chambers, and are designed for different water pressure.

Name Power, W Average annual output, billion kWh Owner Geography Sayano-Shushenskaya HPP 0.00 (6.40)23.50 OAO Rus Hydror. Yenisei, Sayanogorsk Krasnoyarsk HPP6,0020,40Krasnoyarsk HPP JSC Yenisei, Divnogorsk Bratskaya HPP4,5222,60OJSC Irkutskenergo, RFBR. Angara, Bratsk Ust-Ilimskaya HPP3,8421,70OJSC Irkutskenergo, RFFIr. Angara, Ust-Ilimsk, Boguchanskaya HPP3,0017,60JSC Boguchanskaya HPP, JSC RusHydro Angara, Kodinsk Volzhskaya HPP2,5512,30JSC Rus Hydror. Volga, Volzhsky Zhigulevskaya HPP2,3210,50JSC Rus Hydror. Volga, Zhigulevsk Bureiskaya HPP2,017,10JSC Rus Hydror. Bureya, pos. Talakan Cheboksarskaya HPP1,403,31OJSC Rus Hydror. Volga, Novocheboksarsk Saratovskaya HPP1,275,35JSC Rus Hydror. Volga, Balakovo In total, 102 hydroelectric power plants with a capacity of over 100 MW operate in Russia. Major accidents at the hydroelectric power station October 9, 1963 one of the largest hydrotechnical accidents at the Vaiont dam in northern Italy. On September 12, 2007, a major fire broke out at the Novosibirsk hydroelectric power station at one of the transformers due to a short circuit and, as a result, ignition of the bitumen and the casing of the transformer. On August 3, 2009, a fire broke out at the voltage transformer of the 200 kV outdoor switchgear of the Bureyskaya HPP. On August 16, 2009, a fire in the mini-automatic telephone exchange of the Bratskaya HPP, the failure of the communication equipment and telemetry of the HPP (the Bratskaya HPP is one of the three largest hydroelectric power plants in Russia). August 17, 2009 a major accident at the Sayano-Shushenskaya HPP (Sayano-Shushenskaya HPP is the most powerful power plant in Russia).

Since ancient times, people have used the driving force of water. They ground flour in water-driven mills, floated heavy tree trunks downstream, and generally used hydropower to solve a wide variety of tasks, including industrial ones.

First HPPs

At the end of the 19th century, with the beginning of the electrification of cities, hydroelectric power plants began to gain popularity very sharply in the world. In 1878, the world's first hydroelectric power plant appeared in England, which then fed only one arc lamp in the art gallery of the inventor William Armstrong ... And by 1889, there were already 200 hydroelectric power plants in the United States alone.

One of the most important steps in the development of hydropower was the construction of the Hoover Dam in the United States in the 1930s. As for Russia, already in 1892, in Rudny Altai on the Berezovka River, the first four-turbine hydroelectric power station with a capacity of 200 kW was built, designed to provide electricity to the mine drainage of the Zyryanovsky mine. So, with the development of electricity by mankind, hydroelectric power stations marked the rapid course of industrial progress.

Today, modern hydroelectric power plants are huge structures with gigawatts of installed capacity. However, the principle of operation of any hydroelectric power station remains generally quite simple, and almost completely the same everywhere. The pressure of water directed to the blades of the hydroturbine causes it to rotate, and the hydroturbine, in turn, being connected to the generator, rotates the generator. The generator generates electricity, which and.

In the engine room of the hydroelectric power plant, hydraulic units are installed that convert the energy of the water flow into electrical energy, and directly in the building of the hydroelectric power plant there are all the necessary distribution devices, as well as control and monitoring devices for the operation of the hydroelectric power station.

The power of a hydroelectric power plant depends on the amount and pressure of water passing through the turbines. Direct pressure is obtained due to the directed movement of the flow of water. This can be water accumulated near the dam, when a dam is built in a certain place on the river, or the pressure is obtained due to the derivation of the flow - this is when water is diverted from the channel through a special tunnel or channel. So, hydroelectric power stations are dam, diversion and dam-derivation.

The most common dam hydroelectric power plants are based on a dam that blocks the riverbed. Behind the dam, water rises, accumulates, creating a kind of water column that provides pressure and pressure. The higher the dam, the stronger the pressure. At 305 meters high, the world's tallest dam is the 3.6 GW Jinping Dam on the Yalongjiang River in western Sichuan Province in Southwest China.

There are two types of hydroelectric power plants. If the river has a slight fall, but is relatively high in water, then with the help of a dam blocking the river, a sufficient difference in water levels is created.

A reservoir is formed above the dam, which ensures uniform operation of the station throughout the year. Near the shore below the dam, in close proximity to it, a water turbine is installed, connected to an electric generator (dam station). If the river is navigable, then a lock is made on the opposite bank for the passage of ships.

If the river is not very high in water, but has a large fall and rapid flow (for example, mountain rivers), then part of the water is diverted through a special channel, which has a much lower slope than the river. This channel sometimes has a length of several kilometers. Sometimes the terrain conditions force the channel to be replaced by a tunnel (for powerful stations). This creates a significant level difference between the outlet of the canal and the lower reaches of the river.

At the end of the channel, the water enters a pipe with a steep slope, at the lower end of which there is a hydraulic turbine with a generator. Due to the significant difference in levels, the water acquires a large kinetic energy sufficient to power the station (derivation stations).

Such stations can have a large capacity and belong to the category of district power plants (see -). At the smallest stations, the turbine is sometimes replaced by a less efficient, cheaper water wheel.

Types of hydroelectric power plants and their devices

In addition to the dam, the hydroelectric power plant includes a building and a switchgear. The main equipment of the HPP is located in the building, turbines and generators are installed here. In addition to the dam and the building, a hydroelectric power station may have locks, spillways, fish passages and ship lifts.

Each HPP is a unique structure, so the main distinguishing feature of HPPs from other types of industrial power plants is their individuality. By the way, the largest reservoir in the world is located in Ghana, this is the Akosombo reservoir on the Volta River. It occupies 8,500 square kilometers, which is 3.6% of the entire country.

If there is a significant slope along the riverbed, then a diversion hydroelectric power station is built. There is no need to build a large dam reservoir, instead the water is only directed through specially constructed water channels or tunnels directly to the power plant building.

Sometimes small pools of daily regulation are arranged at diversion HPPs, which allow controlling the pressure, and thus influence the amount of electricity generated, depending on the load on the power grid.

Hydrostorage power plants (PSPPs) are a special type of hydroelectric power plants. Here, the station itself is designed to smooth out daily fluctuations and peak loads on, and thereby increase the reliability of the power grid.

Such a station is capable of operating both in generator mode and in accumulative mode, when pumps pump water into the upstream from the downstream. A pool, in this context, is a pool-type facility that is part of a reservoir and is adjacent to a hydroelectric power plant. The upstream is upstream, the downstream is downstream.

An example of a pumped storage power plant is the Taum Sauk reservoir in Missouri, built 80 kilometers from the Mississippi, with a capacity of 5.55 billion liters, allowing the power system to provide a peak capacity of 440 MW.

Hydroelectric stations use the energy of falling water to generate electricity. River water, due to the difference in levels, moves in a continuous stream from the source to the mouth. If you build such a structure as a dam, which will block the movement of the river's water, then the water level in front of the dam will be much higher than after it.

The difference between the upper and lower levels (pool) is called the head, or they can also be called the height of the fall. The principle of operation of a hydroelectric power station is quite simple - a turbine is installed at the level of the downstream and a stream of water from the upstream is directed onto its blades. Under the influence of the force of the falling water flow, the turbine will begin to rotate, setting in motion the rotor of the electric generator, with which it is mechanically connected. The power of hydroelectric power plants directly depends on the magnitude of the pressure, as well as on the amount of water that will pass through all the turbines of the hydroelectric station. The coefficient of performance (COP) of hydroelectric stations is much higher than thermal ones and is about 85%.

According to the nature of the erected structures, hydroelectric power plants are divided into:

• Near-dam - in them the pressure is created by the dam. Such structures are built on flat rivers with little pressure. This is due to the fact that in order to obtain a large pressure, it is necessary to create reservoirs that flood large areas;

• Derivative - a significant pressure is created here due to derivational (bypass) channels. Hydroelectric power stations of this type are built on mountain rivers, because of the large slopes that create the necessary pressure with a relatively low water flow;

Large hydroelectric power plants do not operate in isolation from other power plants. Most often, the operation of hydroelectric power plants is used in parallel with thermal power plants, thereby creating an optimal mode of fuel consumption at thermal power plants and hydroelectric power from hydroelectric power plants. This process is as follows - in winter, when the water level in the rivers is declining and, accordingly, hydroelectric power plants cannot operate at full capacity, then part of the load of the hydroelectric power plant is taken over by the thermal power plant, and in summer, when the water level in the rivers increases, the hydroelectric power plants start working at full capacity, and the TPP reduces the generation of electricity, thereby reducing the consumption of fossil fuels. Thus, there is a saving of funds on solid fuel, which reduces the cost of electrical energy.

Hydroelectric power plants have a number of advantages over thermal power plants, namely:

• The process of generating electricity in a hydroelectric power plant is much simpler than in a thermal one;
• The efficiency of a hydroelectric power plant is much higher than a thermal power plant;
• The cost of electricity generation at large HPPs is about 5 times lower than at TPPs of comparable capacity. This is explained very simply - there is no need for the delivery of organic fuel to the hydroelectric power station, and this minus the price for the fuel itself and its transportation. The HPP does not have the fuel facilities and services needed to maintain it, which reduces the number of maintenance personnel and the cost of spare parts and maintenance.

The main disadvantage of hydroelectric power plants is their lengthy construction and very high cost.