The principle of operation of a thermal power plant scheme. Thermal power plants (CHP, KES): varieties, types, principle of operation, fuel. How coal-fired thermal power plants work

A power station is a power plant that converts natural energy into electrical energy. The most common thermal power plants (TPPs) use thermal energy released during combustion. organic fuel(solid, liquid and gaseous).

Thermal power plants generate about 76% of the electricity produced on our planet. This is due to the presence of fossil fuels in almost all areas of our planet; the possibility of transporting organic fuel from the place of production to the power plant located near energy consumers; technical progress at thermal power plants, which ensures the construction of high-capacity thermal power plants; the possibility of using the waste heat of the working fluid and supplying consumers, in addition to electrical, also thermal energy (with steam or hot water), etc.

A high technical level of the energy sector can only be ensured with a harmonious structure of generating capacities: the energy system should include both nuclear power plants that produce cheap electricity, but with serious restrictions on the range and rate of load change, and thermal power plants that supply heat and electricity, the amount of which depends on the needs for heat, and powerful steam turbine power units operating on heavy fuels, and mobile autonomous gas turbines covering short-term load peaks.

1.1 Types of TES and their features.

On fig. 1 shows the classification of thermal power plants running on fossil fuels.

Fig.1. Types of thermal power plants on organic fuel.

Fig.2 Schematic diagram of thermal power plant

1 - steam boiler; 2 - turbine; 3 - electric generator; 4 - capacitor; 5 - condensate pump; 6 – low pressure heaters; 7 - deaerator; 8 - feed pump; 9 – high pressure heaters; 10 - drainage pump.

A thermal power plant is a complex of equipment and devices that convert fuel energy into electrical and (generally) thermal energy.

Thermal power plants are characterized by great diversity and can be classified according to various criteria.

According to the purpose and type of supplied energy, power plants are divided into regional and industrial.

District power plants are independent public power plants that serve all types of district consumers (industrial enterprises, transport, population, etc.). District condensing power plants, which produce mainly electricity, often retain their historical name - GRES (state district power plants). District power plants that produce electricity and heat (in the form of steam or hot water) are called combined heat and power plants (CHP). As a rule, state district power plants and regional thermal power plants have a capacity of more than 1 million kW.

Industrial power plants are power plants that supply heat and electricity to specific industrial enterprises or their complex, for example, a plant for the production of chemical products. Industrial power plants are part of the industrial enterprises they serve. Their power is determined by the needs industrial enterprises in thermal and electric energy and, as a rule, it is significantly less than that of regional thermal power plants. Often, industrial power plants operate on a common electrical network, but are not subordinate to the power system manager.

According to the type of fuel used, thermal power plants are divided into power plants operating on organic fuel and nuclear fuel.

Behind condensing power plants operating on fossil fuels, at a time when there were no nuclear power plants (NPPs), the name thermal power plants (TPP - thermal power plant) has historically developed. electrical station). It is in this sense that this term will be used below, although CHPPs, NPPs, gas turbine power plants (GTPPs), and combined-cycle power plants (CCPPs) are also thermal power plants operating on the principle of converting thermal energy into electrical energy.

Gaseous, liquid and solid fuels are used as fossil fuels for thermal power plants. Most TPPs in Russia, especially in the European part, consume natural gas as the main fuel, and fuel oil as a reserve fuel, using the latter only in extreme cases due to its high cost; such thermal power plants are called oil-fired. In many regions, mainly in the Asian part of Russia, the main fuel is thermal coal - low-calorie coal or waste from the extraction of high-calorie coal (anthracite sludge - ASh). Since such coals are ground in special mills to a pulverized state before burning, such thermal power plants are called pulverized coal.

According to the type of thermal power plants used at thermal power plants to convert thermal energy into mechanical energy rotation of the rotors of turbine units, distinguish between steam turbine, gas turbine and combined cycle power plants.

The basis of steam turbine power plants are steam turbine plants (STP), which use the most complex, most powerful and extremely advanced energy machine - a steam turbine to convert thermal energy into mechanical energy. PTU is the main element of thermal power plants, thermal power plants and nuclear power plants.

PTU, which have condensing turbines as a drive for electric generators and do not use the heat of the exhaust steam to supply thermal energy to external consumers, are called condensing power plants. PTU equipped with heating turbines and giving off the heat of the exhaust steam to industrial or domestic consumers are called combined heat and power plants (CHP).

Gas turbine thermal power plants (GTPPs) are equipped with gas turbine units (GTUs) operating on gaseous or, in extreme cases, liquid (diesel) fuel. Since the temperature of the gases downstream of the gas turbine is quite high, they can be used to supply thermal energy to an external consumer. Such power plants are called GTU-CHP. Currently, there is one GTPP operating in Russia (GRES-3 named after Klasson, Elektrogorsk, Moscow Region) with a capacity of 600 MW and one GTU-CHPP (in Elektrostal, Moscow Region).

A traditional modern gas turbine plant (GTU) is a combination of an air compressor, a combustion chamber and a gas turbine, as well as auxiliary systems that ensure its operation. The combination of a gas turbine and an electric generator is called a gas turbine unit.

Combined-cycle thermal power plants are equipped with combined-cycle plants (CCGT), which are a combination of GTP and STP, which allows for high efficiency. CCGT-TPPs can be condensing (CCGT-CES) and with heat output (CCGT-CHP). Currently, four new CCGT-CHPPs are operating in Russia (North-West CHPP of St. Petersburg, Kaliningradskaya, CHPP-27 of OAO Mosenergo and Sochinskaya), and a combined heat and power plant has also been built at the Tyumenskaya CHPP. In 2007 Ivanovskaya CCGT-IES was put into operation.

Block TPPs consist of separate, as a rule, the same type of power plants - power units. In the power unit, each boiler supplies steam only for its own turbine, from which it returns after condensation only to its own boiler. According to the block scheme, all powerful state district power plants and thermal power plants are built, which have the so-called intermediate superheating of steam. The operation of boilers and turbines at TPPs with cross-links is provided differently: all boilers of TPPs supply steam to one common steam pipeline (collector) and all steam turbines of TPPs are fed from it. According to this scheme, CPPs are built without intermediate overheating and almost all CHPPs are built for subcritical initial steam parameters.

According to the level of initial pressure, TPPs of subcritical pressure, supercritical pressure (SKP) and super-supercritical parameters (SSCP) are distinguished.

Critical pressure is 22.1 MPa (225.6 atm). In the Russian thermal power industry, the initial parameters are standardized: thermal power plants and thermal power plants are built for subcritical pressure of 8.8 and 12.8 MPa (90 and 130 atm), and for SKD - 23.5 MPa (240 atm). Thermal power plants for supercritical parameters, for technical reasons, are installed with reheat and according to the block scheme. The super-supercritical parameters conditionally include pressure over 24 MPa (up to 35 MPa) and temperature over 5600C (up to 6200C), the use of which requires new materials and new equipment designs. Often, thermal power plants or CHPPs for different levels of parameters are built in several stages - in queues, the parameters of which increase with the introduction of each new queue.

Electricity is produced at power plants by using the energy hidden in various natural resources. As can be seen from Table. 1.2 this happens mainly at thermal (TPP) and nuclear power plants(NPP) operating on the thermal cycle.

Types of thermal power plants

According to the type of energy generated and supplied, thermal power plants are divided into two main types: condensing power plants (CPP), intended only for the production of electricity, and cogeneration, or combined heat and power plants (CHP). Condensing power plants operating on fossil fuels are built near the places of its production, and thermal power plants are located near heat consumers - industrial enterprises and residential areas. CHPPs also operate on fossil fuels, but unlike CPPs, they generate both electrical and thermal energy in the form of hot water and steam for industrial and heating purposes. The main fuels of these power plants include: solid - coal, anthracite, semi-anthracite, brown coal, peat, shale; liquid - fuel oil and gaseous - natural, coke, blast-furnace, etc. gas.

Table 1.2. Electricity generation in the world

Index			2010 (forecast)
Share of total output by power plants, % NPP TPP on gas TPP running on fuel oil
Electricity generation by regions, % Western Europe Eastern Europe Asia and Australia America Middle East and Africa
Installed capacity of power plants in the world (total), GW Including, % NPP TPP on gas TPP running on fuel oil Thermal power plants on coal and other fuels HPPs and power plants on other, renewable, types of fuel
Electricity generation (total), billion kWh

Nuclear power plants are predominantly of the condensing type using the energy of nuclear fuel.

Depending on the type of thermal power plant for driving an electric generator, power plants are divided into steam turbine (STU), gas turbine (GTP), combined-cycle (CCGT) and power plants with internal combustion engines (DPP).

Depending on the duration of work TPP throughout the year according to the coverage of energy load curves, characterized by the number of hours of using the installed capacity τ at st , it is customary to classify power plants into: basic (τ at st > 6000 h/year); semi-peak (τ at st = 2000 - 5000 h/year); peak (τ at st< 2000 ч/год).

Basic power plants are called those that carry the maximum possible constant load for most of the year. In the world energy industry, nuclear power plants, highly economical CPPs, as well as thermal power plants are used as the base ones when working according to the heat schedule. Peak loads are covered by hydroelectric power plants, pumped storage power plants, gas turbines, which have maneuverability and mobility, i.e. fast start and stop. Peak power plants turn on during hours when it is necessary to cover the peak part of the daily electrical load schedule. Semi-peak power plants, with a decrease in the total electrical load, are either transferred to a reduced capacity or placed on standby.

According to the technological structure, thermal power plants are divided into block and non-block. With a block diagram, the main and auxiliary equipment of a steam turbine plant does not have technological connections with the equipment of another power plant installation. For fossil fuel power plants, steam is supplied to each turbine from one or two boilers connected to it. With a non-block scheme of TPP, steam from all boilers enters a common line and is distributed from there to individual turbines.

At condensing power plants that are part of large power systems, only block systems with reheating of steam are used. Non-block circuits with steam and water cross-links are used without intermediate overheating.

The principle of operation and the main energy characteristics of thermal power plants

Electricity at power plants is produced by using the energy hidden in various natural resources (coal, gas, oil, fuel oil, uranium, etc.), according to a fairly simple principle, implementing energy conversion technology. General scheme TPP (see Fig. 1.1) reflects the sequence of such conversion of some types of energy into others and the use of the working fluid (water, steam) in the cycle of a thermal power plant. Fuel (in this case coal) burns in a boiler, heats water and turns it into steam. The steam is fed into turbines that convert the thermal energy of the steam into mechanical energy and drive generators to generate electricity (see section 4.1).

A modern thermal power plant is a complex enterprise, including a large number of different equipment. The composition of the power plant equipment depends on the chosen thermal scheme, the type of fuel used and the type of water supply system.

The main equipment of the power plant includes: boiler and turbine units with an electric generator and a condenser. These units are standardized in terms of power, steam parameters, performance, voltage and current, etc. The type and quantity of the main equipment of a thermal power plant correspond to the given power and the intended mode of its operation. There is also auxiliary equipment that serves to supply heat to consumers and use turbine steam to heat boiler feed water and meet the power plant's own needs. This includes equipment for fuel supply systems, a deaeration-feed plant, a condensing plant, a heating plant (for a CHP plant), technical water supply systems, oil supply, regenerative heating of feed water, chemical water treatment, distribution and transmission of electricity (see Section 4).

All steam turbine plants use regenerative feed water heating, which significantly increases the thermal and overall efficiency of the power plant, since in schemes with regenerative heating, steam flows discharged from the turbine to regenerative heaters do work without loss in the cold source (condenser). At the same time, for the same electric power of the turbogenerator, the steam flow in the condenser decreases and, as a result, the efficiency installations is growing.

The type of steam boiler used (see section 2) depends on the type of fuel used in the power plant. For the most common fuels (fossil coal, gas, fuel oil, freztorf), boilers with a U-, T-shaped and tower layout and a combustion chamber designed for a particular type of fuel are used. For fuels with fusible ash, boilers with liquid ash removal are used. At the same time, high (up to 90%) ash capture in the furnace is achieved and abrasive wear of heating surfaces is reduced. For the same reasons, for high-ash fuels such as oil shale and coal preparation waste, steam boilers with a four-pass layout are used. At thermal power plants, as a rule, drum or once-through boilers are used.

Turbines and electric generators are consistent on a power scale. Each turbine corresponds to a certain type of generator. For block thermal condensing power plants, the power of the turbines corresponds to the power of the units, and the number of units is determined by the given power of the power plant. Modern units use 150, 200, 300, 500, 800 and 1200 MW condensing turbines with steam reheat.

CHPPs use turbines (see subsection 4.2) with backpressure (type P), with condensation and production steam extraction (type P), with condensation and one or two heat extractions (type T), as well as with condensation, industrial and heat extraction steam (type PT). Turbines of the PT type can also have one or two heat extractions. The choice of turbine type depends on the magnitude and ratio of thermal loads. If the heating load prevails, then in addition to the PT turbines, turbines of the T type with heat extraction can be installed, and if the industrial load prevails, turbines of the PR and R types with industrial extraction and back pressure can be installed.

At present, at CHPPs, installations with an electric power of 100 and 50 MW, operating at initial parameters of 12.7 MPa, 540–560 ° C, are most widely used. For CHPPs in large cities, installations with an electric capacity of 175–185 MW and 250 MW (with a T-250-240 turbine) have been created. Units with T-250-240 turbines are modular and operate at supercritical initial parameters (23.5 MPa, 540/540°C).

A feature of the operation of power plants in the network is that the total amount of electrical energy generated by them at any given time must fully correspond to the energy consumed. The main part of the power plants operate in parallel in the integrated energy system, covering the total electrical load of the system, and the CHPP simultaneously covers the heat load of its area. There are local power plants designed to serve the area and are not connected to the general power system.

A graphic representation of the dependence of power consumption over time is called electrical load schedule. Daily schedules of electrical load (Fig. 1.5) vary depending on the time of year, day of the week and are usually characterized by a minimum load at night and a maximum load at peak hours (peak part of the graph). Along with the daily schedules, the annual schedules of the electrical load (Fig. 1.6), which are built according to the daily schedules, are of great importance.

Electrical load graphs are used in planning the electrical loads of power plants and systems, distributing loads between individual power plants and units, in calculations for choosing the composition of working and standby equipment, determining the required installed power and the necessary reserve, the number and unit power of units, in developing equipment repair plans and determination of the repair reserve, etc.

When operating at full load, power plant equipment develops rated or the longest power (capacity), which is the main passport characteristic of the unit. At this maximum power (productivity), the unit must operate for a long time at the nominal values of the main parameters. One of the main characteristics of a power plant is its installed capacity, which is defined as the sum of the nominal capacities of all electric generators and heating equipment, taking into account the reserve.

The operation of the power plant is also characterized by the number of hours of use installed capacity, which depends on the operating mode of the power plant. For base load power plants, the number of hours of installed capacity use is 6000–7500 h/year, and for those operating in peak load mode, less than 2000–3000 h/year.

The load at which the unit operates with the greatest efficiency is called the economic load. The rated continuous load can be equal to the economic one. Sometimes short-term operation of equipment with a load of 10-20% higher than the nominal load with lower efficiency is possible. If the equipment of the power plant works stably with the design load at the nominal values of the main parameters or when they change within acceptable limits, then this mode is called stationary.

Modes of operation with steady loads, but different from the calculated ones, or with unsteady loads are called non-stationary or variable modes. With variable modes, some parameters remain unchanged and have nominal values, while others change within certain allowable limits. So, at partial load of the unit, the pressure and temperature of the steam in front of the turbine can remain nominal, while the vacuum in the condenser and steam parameters in the extractions will change in proportion to the load. Non-stationary modes are also possible, when all the main parameters change. Such modes take place, for example, when starting and stopping equipment, dumping and picking up the load on a turbogenerator, when operating on sliding parameters, and are called non-stationary.

The heat load of the power plant is used for technological processes and industrial installations, for heating and ventilation of industrial, residential and public buildings, air conditioning and domestic needs. For industrial purposes, steam pressure is usually required from 0.15 to 1.6 MPa. However, in order to reduce losses during transportation and avoid the need for continuous drainage of water from communications, steam is released from the power plant somewhat overheated. For heating, ventilation and domestic needs, the CHP plant usually supplies hot water with a temperature of 70 to 180°C.

Thermal load, determined by the heat consumption per production processes and domestic needs (hot water), depends on the outside air temperature. In the conditions of Ukraine in summer this load (as well as electrical) is less than in winter. Industrial and domestic heat loads change during the day, in addition, the average daily heat load of the power plant, spent on domestic needs, changes on weekdays and weekends. Typical graphs of changes in the daily heat load of industrial enterprises and hot water supply of a residential area are shown in Figures 1.7 and 1.8.

The efficiency of TPP operation is characterized by various technical and economic indicators, some of which assess the perfection of thermal processes (efficiency, heat and fuel consumption), while others characterize the conditions in which TPP operates. For example, in fig. 1.9 (a, b) shows the approximate heat balances of CHP and IES.

As can be seen from the figures, the combined generation of electric and thermal energy provides a significant increase in the thermal efficiency of power plants due to a decrease in heat losses in turbine condensers.

The most important and complete indicators of TPP operation are the cost of electricity and heat.

Thermal power plants have both advantages and disadvantages in comparison with other types of power plants. The following advantages of TPP can be indicated:

relatively free territorial distribution associated with the wide distribution of fuel resources;
the ability (unlike HPPs) to generate energy without seasonal power fluctuations;
the area of alienation and withdrawal from economic circulation of land for the construction and operation of thermal power plants, as a rule, is much less than is necessary for nuclear power plants and hydroelectric power plants;
Thermal power plants are built much faster than hydroelectric power plants or nuclear power plants, and their unit cost per unit of installed capacity is lower compared to nuclear power plants.
At the same time, TPPs have major disadvantages:
the operation of thermal power plants usually requires much more personnel than for hydroelectric power plants, which is associated with servicing a very large-scale fuel cycle;
the operation of TPPs depends on the supply of fuel resources (coal, fuel oil, gas, peat, oil shale);
variability of operating modes of thermal power plants reduce efficiency, increase fuel consumption and lead to increased equipment wear;
existing thermal power plants are characterized by relatively low efficiency. (mainly up to 40%);
TPPs have a direct and adverse impact on environment and are not environmentally "clean" sources of electricity.
The greatest damage to the ecology of the surrounding regions is caused by coal-fired power plants, especially high-ash coal. Among TPPs, the most "clean" are stations that use natural gas in their technological process.

According to experts, thermal power plants around the world annually emit about 200–250 million tons of ash, more than 60 million tons of sulfur dioxide, a large amount of nitrogen oxides and carbon dioxide (causing the so-called greenhouse effect and leading to long-term global climate change), absorbing large amounts of oxygen. In addition, by now it has been established that the excess radiation background around coal-fired thermal power plants is, on average, 100 times higher in the world than near a nuclear power plant of the same capacity (coal almost always contains uranium, thorium and a radioactive isotope of carbon as trace impurities). ). However, well-established technologies for the construction, equipment and operation of thermal power plants, as well as the lower cost of their construction, lead to the fact that thermal power plants account for the bulk of world electricity production. For this reason, much attention is paid to the improvement of TPP technologies and the reduction of their negative impact on the environment throughout the world (see Section 6).

TPP is a power plant that generates electrical energy as a result of the conversion of thermal energy released during the combustion of fossil fuels (Fig. D.1).

There are thermal steam turbine power plants (TPES), gas turbine (GTES) and combined-cycle (PGES). Let's take a closer look at TPES.

Fig. E.1 Scheme of TPP

At TPPP, thermal energy is used in a steam generator to produce high-pressure water vapor, which drives the steam turbine rotor connected to the electric generator rotor. Such thermal power plants use coal, fuel oil, natural gas, lignite (brown coal), peat, and shale as fuel. Their efficiency reaches 40%, power - 3 GW. TPES, which have condensing turbines as a drive for electric generators and do not use the heat of the exhaust steam to supply thermal energy to external consumers, are called condensing power plants (the official name in the Russian Federation is the State District Electric Power Plant, or GRES). The GRES generates about 2/3 of the electricity produced at the TPP.

TPES equipped with heating turbines and giving off the heat of the exhaust steam to industrial or domestic consumers are called combined heat and power plants (CHP); they produce about 1/3 of the electricity produced at thermal power plants.

Four types of coal are known. In order of increasing carbon content, and thus calorific value, these types are arranged as follows: peat, brown coal, bituminous (fat) coal or hard coal and anthracite. In the operation of TPPs, mainly the first two types are used.

Coal is not chemically pure carbon, it also contains inorganic material (up to 40% carbon in brown coal), which remains after coal combustion in the form of ash. Sulfur can be found in coal, sometimes as iron sulfide and sometimes as organic constituents of the coal. Coal usually contains arsenic, selenium, and radioactive elements. In fact, coal is the dirtiest of all fossil fuels.

When coal is burned, carbon dioxide, carbon monoxide are formed, as well as sulfur oxides, suspended particles and nitrogen oxides in large quantities. Sulfur oxides damage trees, various materials and have a detrimental effect on people.

The particles released into the atmosphere when coal is burned in power plants are called "fly ash". Ash emissions are strictly controlled. About 10% of suspended particles actually enter the atmosphere.

A coal-fired power plant with a capacity of 1000 MW burns 4-5 million tons of coal per year.

Since there is no coal mining in the Altai Territory, we will assume that it is brought from other regions, and roads are laid for this, thereby changing the natural landscape.

APPENDIX E

In the first years of Soviet power, under the leadership of Lenin, a plan was developed for the construction of power plants and the electrification of Russia - the GOELRO plan. Vladimir Ilyich called this plan the second program of the Party. When discussing it, Lenin said: "Communism is Soviet power plus the electrification of the whole country."

Modern production cannot be imagined without electric motors that drive various machines, devices, automatic lines. No automated control system will work without electricity technological process. Electricity is widely used in agriculture, railway and urban transport. Today, electricity is a constant companion of man. Electric power plants are power plants. The first-born of GOELRO, the Volkhovskaya HPP had a capacity of only 66,000 kW. And the Volga Hydroelectric Power Plant named after the 22nd Congress of the CPSU, built in the post-war years, had a capacity of 2 million 500 thousand kW. The main types of power plants: hydraulic and thermal.

Thermal power plants

At a thermal power plant, electricity is obtained from the energy contained in the fuel. The main parts of a thermal power plant are as follows: a fuel store and devices for distinguishing coal, a steam boiler and a turbine with a generator.

Coal enters the fuel depot. A special mechanism - a wagon dumper loads coal into the bunker. Belt conveyors feed it to a ball mill, where the coal is ground into dust. Coal dust goes through pipes to a separate compartment where steam boilers are located. A modern steam boiler is a large structure as high as a multi-storey building. Together with hot air, coal dust is blown into the boiler furnace. Oil or gas can be used as fuel. In the boiler furnace, the dust burns in the form of a torch, while a large amount of heat is released. The water in the pipes is heated and turns into steam. The steam is collected in the upper drum of the boiler. Then it passes through a coil, a superheater, where it is heated to a temperature of 400 - 500 degrees. From the boiler, the superheated steam enters the steam turbine installed in the engine room of the power plant through a pipeline. A steam turbine is a heat engine that converts steam energy into mechanical energy of shaft rotation. The steam from the boiler enters the turbine under high pressure. The turbine has a system of fixed blades between which are located the blades of the impellers mounted on the shaft. Consider the operation of one of the wheels. In the channels between the rotor blades, the direction of steam movement changes, while the steam acts on the blades and rotates the turbine shaft with high speed 3000 rpm. The exhaust steam from the turbine enters the condenser. Cold water circulates in the condenser tubes, the water obtained from the steam is fed back to the boiler by the feed pump. The mechanical energy of the turbine is converted into electrical energy in a generator whose shaft is connected to the turbine shaft. Consider the generator in the context. It consists of a stator and a rotor. A direct current from an external source passes through the brushes and rings through the rotor winding. When the rotor rotates, its magnetic field flows into the stator winding. AC is induced in the stator windings electricity high power. This current is fed to the step-up substation. In accordance with the law of conservation and transformation of energy, the power plant does not create energy. It only converts the chemical energy contained in the fuel into steam energy, which in turn is converted into mechanical energy and then into electrical energy. The efficiency of a thermal power plant is approximately 25%. Turbines with a capacity of 150,000 to 200,000 kilowatts operate at large Soviet power plants. Turbines with a capacity of 300,000 kilowatts have been created. Powerful generators give a current of tens of thousands of amperes at a voltage of about 10,000 volts. Thermal power plants are usually built where there are fuel reserves. Coal, gas, peat. Electricity is transmitted by wire to consumers for hundreds of kilometers. Since the current power is equal to the product of the current strength and voltage, then at a low voltage the current strength will be very significant. The wires will get very hot, which will lead to large losses of electricity. To reduce power losses, it would be possible to reduce the resistance of the wires by increasing their cross section. But then a large amount of metal would have to be used up. How can this be avoided? It is necessary to reduce the current strength by increasing the voltage by the same amount. It will only be necessary to ensure better insulation of the wires. Transformers are used to convert current and voltage. They increase the voltage and consequently decrease the current. The power of the current remains unchanged. Voltage up to 500 kV is used for long-distance power transmission. The high voltage current is transmitted through overhead lines to the place of consumption. Here, the current flows to the main step-down substation, where its voltage is reduced to 6,600 volts with the help of transformers. From the step-down substation, through overhead lines and underground cables, current flows to other substations located at enterprises and city streets. Here the voltage is again reduced from 6,600 volts, to the value used in everyday life and in production.

Combined heat and power plants (CHP)

for heating houses and industrial premises it takes a lot of heat. It can be obtained from combined heat and power plants (CHP). These are power plants that, along with electricity, give off a significant part of the heat to nearby consumers. The heating of water supplied by the CHPP for heating and domestic needs of the population is carried out in special steam-water heaters. Consider the scheme of CHP. The exhaust steam from the turbine enters the heat exchanger. Here it condenses and the condensate is returned to the boiler. The water circulating in the tubes of the heat exchanger is heated and pumped to the heating system.

hydroelectric power plants

Much attention is paid in our country to the construction of a hydroelectric power station. The presence of large rivers creates favorable conditions for the construction of powerful hydroelectric power plants. The hydropower resources of our country amount to 420 million kW. The power plant is the main part of the hydroelectric complex. The structure of the hydroelectric complex includes a spillway reinforced concrete dam for passing water into floods, an earthen dam, a shipping lock, a breakwater, irrigation and other structures. Platinum constructed across the river divides it into the upper part - the upper pool, where water accumulates, and the lower part of the downstream. The difference in the level of the river between the upper and lower pools forms the pressure created by the platinum and used by the turbines. The water retained by platinum passes through the channel into the spiral chamber, which encloses the impeller of the hydraulic turbine. From the spiral chamber, water enters the blades of the impeller of the hydraulic turbine at high speed and rotates it. The generator rotor shaft is connected to the turbine shaft. A hydro turbine and a generator form a hydraulic unit. During the operation of the hydraulic unit, mechanical energy is converted into electrical energy. Having completed work in the hydroturbine, the water flows through the channel to the downstream. Hydroelectric power plants are characterized by high efficiency, they use more than 90% of the energy of the water flow. Hydroelectric power plants do not consume fuel. They are served by a small staff. All this reduces the cost of electricity. Like a thermal power plant, a hydraulic power plant does not create energy, it only converts mechanical energy into electrical energy. From the generators, electric current is supplied to the transformers of the step-up substation, and from there through high-voltage power lines to distant consumers. A reservoir is created near the dam of the hydroelectric power station, where a large amount of water is accumulated, which ensures the operation of the hydroelectric power station throughout the year. The hydroelectric power station uses the energy of only a certain section of the river. For a more complete use of the energy of the river, a cascade of power plants is being built. This is the name of several power plants located one after the other.

High-voltage transmission lines connect thermal and hydroelectric power plants, combining them into a power system. Hydroelectric power plants make full use of floods and produce the greatest amount of electricity during these periods, while thermal power plants can repair boilers and turbines during this period. In the event of an emergency shutdown of one of the stations, other stations of the power system take over its electrical load. The units are controlled by systems centrally from the control room. After the launch of two super-powerful hydroelectric power plants on the Volga, a unified energy system of the European part of the Soviet Union was created.

Thermal power plants are a device whose specialization is based on the generation of electricity. Electricity is produced by converting and processing thermal energy. heat is generated by the combustion of a fuel resource, which can be varieties of fossil fuels. The ability to convert the energy of natural resources into electricity makes TPP an integral part of the life of any modern person.

Small-scale thermal power plants are widely used in various fields. For example, they can heat and supply electricity to schools and swimming pools, clinics and sports complexes. They can be used to create normal working conditions in temporary huts and trailers during construction, in other areas of the national economy.

These power plants have a lot of pluses and very few minuses. Mini thermal power plants consist of several devices and their operation is fully automated. Also, TPP can work on any type of fuel which allows it to be used in any conditions.

The main advantage of this technique can be considered that it allows you not to depend on rising heat prices and electricity and have their own independent mini thermal power plant. This is an opportunity to save money allocated for this by almost 100%.

The possibilities of the equipment are almost limitless, because it can provide, in fact, any room in terms of category no worse than centralized networks, but it will cost much less. The initial costs will quickly pay off and the costs will be minimal only for fuel for CHP. Moreover, it can also be varied depending on the operating conditions, choosing a cheaper option.

Advantages of TPP

Relatively low price indicator of the thermal resource used during the operation of TPPs, in comparison with the price categories of a similar resource used at nuclear power plants.
The construction of a thermal power plant, as well as bringing the facility to a state of active operation, involves a smaller attraction of funds.
TPP can be territorially located at any geographical point. The organization of the work of this type of station will not require linking the location of the station installation in close proximity to certain natural resources. Fuel can be delivered to the station from anywhere in the world using road or rail transport.
The relatively small scale of thermal power plants allows them to be installed in countries where land is a valuable resource due to its small territory, and the percentage of land that has fallen into the exclusion zone and withdrawal from agricultural needs is also significantly reduced.
The cost of fuel produced by thermal power plants, in comparison with similar diesel, will be cheaper.
The generated energy does not depend on seasonal fluctuations in power, which is typical of hydroelectric power plants.
Maintenance and operation of TPPs are characterized by simplicity.
The technological process of building thermal power plants has been mastered in large quantities, which makes it possible for their rapid construction, which significantly saves time resources.
At the end of the service life of thermal power plants, they can be easily recycled. The infrastructure subdivision of a thermal power plant is more durable than the main equipment represented by boilers and turbines. Water supply and heat supply systems are capable of maintaining their quality and technological characteristics, they can continue to function after the replacement of turbines and boilers.
During operation, water and steam are released, which can be used to organize the heating process or in other technological tasks.
Are manufacturers about 80% of all electricity in the country.
The simultaneous generation of electricity and the implementation of heat supply with a long service life make TPPs economical systems.

Disadvantages of TPP

Ecological imbalance and air pollution in the process of ejecting smoke and soot into it, sulfur and nitrogen compounds in large quantities. The activity of thermal power plants can provoke the phenomenon of the "greenhouse effect" and the passage of acid rain. In addition, the generation and transmission of electricity lead to electromagnetic pollution of the environment.
In connection with the extraction of a large amount of coal for the operation and operation of thermal power plants, there is a need for mines, during the creation of which the natural relief is disturbed.
Violation of the thermal balance of water bodies, which occurs in the process of TPP discharge of cooling water, which leads to an increase in temperature indicators.
Together with the gases polluting the atmosphere, the thermal power plant releases some substances belonging to the group of radioactive substances, the content of which is traced to a greater or lesser extent in the fuel.
During the operation of thermal power plants, those natural resources are used, the natural renewal of which is impossible, therefore, the amount of these resources is gradually decreasing.
The presence of relatively low profitability.
TPPs find it difficult to cope with the need to take part in covering the variable part of the daily electrical load schedule.
The ability of TPPs to operate on imported fuel contains a problem associated with the precise organization of the process of supplying fuel resources.
The operation of thermal power plants entails higher maintenance costs compared to hydroelectric power plants.

When to choose this equipment

When the costs of transmission or generation of electricity are high and the budget of an organization or individual cannot afford them. If the centralized systems for the supply of heat and electricity cannot overpower the additionally built or put into operation areas.

When the amount of electricity is simply not enough for the smooth operation of modern equipment and appliances. Either it has low quality. Also, we should not forget about the environmental component of the equipment, which allows you to release harmful substances into the atmosphere.

Versatility and economy

Power plants can run on wood or coal, gas, diesel fuel. Usually, diesel fuel is rarely used due to its high cost and harmful emissions. There are several modifications of these installations and distinguish between:

Steam turbines.
gas turbines.
Gas piston generators.

The choice of TPP depends on the required power for the consumer. Gas piston engines are considered the most popular, however, their power is only 80 mW.

Absolute benefits against the backdrop of the crisis

Generally the pros far outweigh the cons, and for some enterprises and institutions, the purchase of a mini thermal power plant is an excellent way out, especially if the city is growing, but there are no opportunities to lay heat and electricity networks. Or they are loaded so much that in any case the supply of heat or light will not be enough. It can also be an excellent solution in a suburban area, where there is no centralized supply of heat and electricity at all, but housing is being built nonetheless. The capabilities of such installations will be especially appreciated by workers who repair routes and roads, drillers, oil workers who move around the country, but they do not have the opportunity to connect to a centralized supply of light and heat every time.

Perhaps the TPP will be useful for military garrisons that serve far from the towns, with full provision of comfortable conditions. In a word, this equipment can become indispensable in areas where the opportunity to get full heat, electricity and even cold air for air conditioners is especially appreciated if necessary. Small equipment can be easily transported by special vehicles and used as needed.

TPP data will also be beneficial for entrepreneurs who occupy space in garages, warehouses, and are not connected to centralized heat, but use light at high city tariffs. This will help to significantly save on material costs during work and allow you not to depend on heat and light monopolists.

The ideal capabilities of the mini version of the TPP can only compete with large samples thermal power plants or hydroelectric power plants, but the mobility and automation of small equipment outweighs in any case.

conclusions

Due to the fact that the problem of energy is relevant for today, questions arise about the organization of providing the population with electricity, while avoiding significant financial and time costs while maintaining a favorable environmental situation. One of the options for solving this problem is the construction and operation of thermal power plants.