Physical foundations of electrical energy production. Production, transmission and consumption of electrical energy. Main sources of electricity

Generation of electrical energy Electric current is generated in generators-devices that convert energy of one kind or another into electrical energy. The predominant role in our time is played by electromechanical induction alternating current generators. There mechanical energy is converted into electrical energy. Electric current is generated in generators-devices that convert energy of one kind or another into electrical energy. The predominant role in our time is played by electromechanical induction alternating current generators. There mechanical energy is converted into electrical energy. The generator consists of A generator consists of a permanent magnet that creates a magnetic field and a winding in which an alternating emf is induced. a permanent magnet that creates a magnetic field, and a winding in which an alternating emf is induced.

Transformers TRANSFORMER is a device that converts alternating current of one voltage into alternating current of another voltage at a constant frequency. In the simplest case, the transformer consists of a closed steel core, on which two coils with wire windings are placed. The one of the windings that is connected to an alternating voltage source is called primary, and the one to which the “load” is connected, i.e., devices that consume electricity, is called secondary. The operation of a transformer is based on the phenomenon of electromagnetic induction.

Electrical energy production Electricity is produced at large and small power plants, mainly using electromechanical induction generators. There are several types of power plants: thermal, hydroelectric and nuclear power plants. NPP GESTThermal power plants

Use of electricity The main consumer of electricity is industry, which accounts for about 70% of the electricity produced. Transport is also a major consumer. An increasing number of railway lines are being converted to electric traction. Almost all villages and villages receive electricity from state power plants for industrial and domestic needs. About a third of the electricity consumed by industry is used for technological purposes (electric welding, electrical heating and melting of metals, electrolysis, etc.).

Electricity transmission Energy transmission is associated with noticeable losses: electric current heats the wires of power lines. If the line length is very long, energy transmission may become economically unprofitable. Since current power is proportional to the product of current and voltage, to maintain the transmitted power, it is necessary to increase the voltage in the transmission line. That's why step-up transformers are installed at large power plants. They increase the voltage in the line by the same amount as they decrease the current. To directly use electricity, step-down transformers are installed at the ends of the line. Step-up transformer Step-down transformer Step-down transformer Step-down transformer To consumer Generator 11 kV 110 kV 35 kV 6 kV Transmission line Transmission line Transmission line 35 kV 6 kV 220 V

Efficient use of electricity The demand for electricity is constantly increasing. There are two ways to satisfy this need. The most natural and at first glance the only way is the construction of new powerful power plants. But thermal power plants consume non-renewable natural resources, and also cause great damage to the ecological balance on our planet. Advanced technologies make it possible to meet energy needs in a different way. Priority should be given to increasing energy efficiency rather than increasing power plant capacity.

All technological processes of any production are associated with energy consumption. The vast majority of energy resources are spent on their implementation.

The most important role in an industrial enterprise is played by electrical energy - the most universal type of energy, which is the main source of mechanical energy.

The conversion of various types of energy into electrical energy occurs at power plants .

Power plants are enterprises or installations designed to produce electricity. The fuel for power plants is natural resources - coal, peat, water, wind, sun, nuclear energy, etc.

Depending on the type of converted energy, power plants can be divided into the following main types: thermal, nuclear, hydroelectric power plants, pumped storage, gas turbine, as well as low-power local power stations - wind, solar, geothermal, tidal, diesel, etc.

The bulk of electricity (up to 80%) is generated at thermal power plants (TPPs). The process of obtaining electrical energy at thermal power plants consists of the sequential conversion of the energy of burned fuel into the thermal energy of water steam, which drives the rotation of a turbine unit (steam turbine connected to a generator). The mechanical energy of rotation is converted by the generator into electrical energy. The fuel for power plants is coal, peat, oil shale, natural gas, oil, fuel oil, and wood waste.

With economical operation of thermal power plants, i.e. when the consumer simultaneously supplies optimal amounts of electricity and heat, their efficiency reaches more than 70%. During the period when heat consumption completely stops (for example, during the non-heating season), the efficiency of the station decreases.

Nuclear power plants (NPPs) differ from a conventional steam turbine station in that a nuclear power plant uses the process of fission of uranium, plutonium, thorium, etc. nuclei as an energy source. As a result of the splitting of these materials in special devices - reactors, a huge amount of thermal energy is released.

Compared to thermal power plants, nuclear power plants consume a small amount of fuel. Such stations can be built anywhere, because they are not related to the location of natural fuel reserves. In addition, the environment is not polluted by smoke, ash, dust and sulfur dioxide.

In hydroelectric power plants (HPPs), water energy is converted into electrical energy using hydraulic turbines and generators connected to them.

There are dam and diversion types of hydroelectric power stations. Dam hydroelectric power plants are used on lowland rivers with low pressures, diversion hydroelectric power stations (with bypass canals) are used on mountain rivers with large slopes and low water flow. It should be noted that the operation of hydroelectric power plants depends on the water level determined by natural conditions.

The advantages of hydroelectric power plants are their high efficiency and low cost of generated electricity. However, one should take into account the high cost of capital costs in the construction of hydroelectric power plants and the significant time required for their construction, which determines their long payback period.

A peculiarity of the operation of power plants is that they must generate as much energy as is currently required to cover the load of consumers, the stations’ own needs and losses in the networks. Therefore, station equipment must always be ready for periodic changes in consumer load throughout the day or year.

Most power plants are integrated into energy systems , each of which has the following requirements:

• Correspondence of the power of generators and transformers to the maximum power of electricity consumers.
• Sufficient capacity of power transmission lines (PTL).
• Ensuring uninterrupted power supply with high energy quality.
• Cost-effective, safe and easy to use.

To meet these requirements, power systems are equipped with special control centers equipped with monitoring, control, communication means and special layouts of power plants, transmission lines and step-down substations. The control center receives the necessary data and information about the state of the technological process at power plants (water and fuel consumption, steam parameters, turbine rotation speed, etc.); about the operation of the system - which elements of the system (lines, transformers, generators, loads, boilers, steam pipelines) are currently disconnected, which are in operation, in reserve, etc.; about the electrical parameters of the mode (voltages, currents, active and reactive powers, frequency, etc.).

The operation of power plants in the system makes it possible, due to a large number of parallel operating generators, to increase the reliability of power supply to consumers, to fully load the most economical units of power plants, and to reduce the cost of electricity generation. In addition, the installed capacity of backup equipment in the power system is reduced; ensures higher quality of electricity supplied to consumers; the unit power of the units that can be installed in the system increases.

In Russia, as in many other countries, three-phase alternating current with a frequency of 50 Hz is used for the production and distribution of electricity (in the USA and a number of other countries, 60 Hz). Three-phase current networks and installations are more economical compared to single-phase alternating current installations, and also make it possible to widely use the most reliable, simple and cheap asynchronous electric motors as an electric drive.

Along with three-phase current, some industries use direct current, which is obtained by rectifying alternating current (electrolysis in the chemical industry and non-ferrous metallurgy, electrified transport, etc.).

Electrical energy generated at power plants must be transferred to places of consumption, primarily to large industrial centers of the country, which are many hundreds and sometimes thousands of kilometers away from powerful power plants. But transmitting electricity is not enough. It must be distributed among many different consumers - industrial enterprises, transport, residential buildings, etc. Electricity transmission over long distances is carried out at high voltage (up to 500 kW or more), which ensures minimal electrical losses in power lines and results in large savings in materials due to reduction in wire cross-sections. Therefore, in the process of transmitting and distributing electrical energy, it is necessary to increase and decrease the voltage. This process is carried out through electromagnetic devices called transformers. A transformer is not an electrical machine, because its work is not related to the conversion of electrical energy into mechanical energy and vice versa; it only converts voltage into electrical energy. The voltage is increased using step-up transformers at power plants, and the voltage is decreased using step-down transformers at consumer substations.

The intermediate link for transmitting electricity from transformer substations to electricity receivers are Electricity of the net .

A transformer substation is an electrical installation designed for the conversion and distribution of electricity.

Substations can be closed or open depending on the location of its main equipment. If the equipment is located in a building, then the substation is considered closed; if in the open air, then open.

Substation equipment can be assembled from individual device elements or from blocks supplied assembled for installation. Substations of block design are called complete.

Substation equipment includes devices that switch and protect electrical circuits.

The main element of substations is the power transformer. Structurally, power transformers are designed in such a way as to remove as much heat as possible from the windings and core into the environment. To do this, for example, the core with windings is immersed in a tank with oil, the surface of the tank is made ribbed, with tubular radiators.

Complete transformer substations installed directly in production premises with a capacity of up to 1000 kVA can be equipped with dry-type transformers.

To increase the power factor of electrical installations, static capacitors are installed at substations to compensate for the reactive power of the load.

An automatic monitoring and control system for substation devices monitors the processes occurring in the load and in the power supply networks. It performs the functions of protecting the transformer and networks, disconnects protected areas using a switch during emergency conditions, performs restarting, and automatically switching on the reserve.

Transformer substations of industrial enterprises are connected to the power supply network in various ways, depending on the requirements for the reliability of uninterrupted power supply to consumers.

Typical schemes providing uninterrupted power supply are radial, main or ring.

In radial schemes, lines that supply large electrical receivers depart from the distribution board of the transformer substation: motors, group distribution points, to which smaller receivers are connected. Radial circuits are used in compressor and pumping stations, workshops of explosion- and fire-hazardous, dusty industries. They provide high reliability of power supply, allow the widespread use of automatic control and protection equipment, but require high costs for the construction of distribution boards, laying cables and wires.

Trunk circuits are used when the load is evenly distributed over the workshop area, when there is no need to build a switchboard at the substation, which reduces the cost of the facility; prefabricated busbars can be used, which speeds up installation. At the same time, moving technological equipment does not require reworking the network.

The disadvantage of the main circuit is the low reliability of the power supply, since if the main line is damaged, all electrical receivers connected to it are switched off. However, installing jumpers between the mains and using protection significantly increases the reliability of power supply with minimal costs for redundancy.

From the substations, the low-voltage current of industrial frequency is distributed throughout the workshops using cables, wires, busbars from the workshop switchgear to the electric drive devices of individual machines.

Interruptions in the power supply to enterprises, even short-term ones, lead to disruptions in the technological process, spoilage of products, damage to equipment and irreparable losses. In some cases, a power outage can create an explosion and fire hazard in enterprises.

According to the electrical installation rules, all electrical energy receivers are divided into three categories according to the reliability of power supply:

• Energy receivers for which an interruption in power supply is unacceptable, since it can lead to equipment damage, massive product defects, disruption of a complex technological process, disruption of the operation of particularly important elements of the municipal economy and, ultimately, threaten people’s lives.
• Energy receivers, a break in the power supply of which leads to failure to fulfill the production plan, downtime of workers, machinery and industrial transport.
• Other receivers of electrical energy, for example non-serial and auxiliary production shops, warehouses.

The power supply to electrical energy receivers of the first category must be ensured in any case and, if disrupted, it must be automatically restored. Therefore, such receivers must have two independent power sources, each of which can fully supply them with electricity.

Electricity receivers of the second category may have a backup power supply source, which is connected by duty personnel after a certain period of time after the failure of the main source.

For receivers of the third category, as a rule, a backup power source is not provided.

The power supply of enterprises is divided into external and internal. External power supply is a system of networks and substations from the power source (energy system or power plant) to the transformer substation of the enterprise. Energy transmission in this case is carried out via cable or overhead lines with rated voltages of 6, 10, 20, 35, 110 and 220 kV. Internal power supply includes the energy distribution system within the workshops of the enterprise and on its territory.

A voltage of 380 or 660 V is supplied to the power load (electric motors, electric furnaces), and 220 V to the lighting load. In order to reduce losses, it is advisable to connect motors with a power of 200 kW or more to a voltage of 6 or 10 kV.

The most common voltage in industrial enterprises is 380 V. Voltage 660 V is being widely introduced, which makes it possible to reduce energy losses and consumption of non-ferrous metals in low-voltage networks, increase the range of workshop substations and the power of each transformer to 2500 kVA. In some cases, at a voltage of 660 V, the use of asynchronous motors with a power of up to 630 kW is economically justified.

Electricity distribution is carried out using electrical wiring - a set of wires and cables with associated fastenings, supporting and protective structures.

Internal wiring is electrical wiring installed inside a building; external - outside, along the outer walls of the building, under canopies, on supports. Depending on the installation method, internal wiring can be open if it is laid on the surface of walls, ceilings, etc., and hidden if it is laid in the structural elements of buildings.

The wiring can be laid with insulated wire or unarmored cable with a cross-section of up to 16 sq. mm. In places of possible mechanical impact, electrical wiring is enclosed in steel pipes and sealed if the room environment is explosive or aggressive. On machine tools and printing machines, wiring is carried out in pipes, in metal sleeves, with wire with polyvinyl chloride insulation, which is not destroyed by exposure to machine oils. A large number of wires of the machine's electrical wiring control system are laid in trays. Busbar trunking is used to transmit electricity in workshops with a large number of production machines.

For the transmission and distribution of electricity, power cables in rubber and lead sheaths are widely used; unarmored and armored. Cables can be laid in cable channels, mounted on walls, in earthen trenches, or embedded in walls.

Electricity, as the fundamental engine of the development of civilization, entered the life of mankind relatively recently. The active use of electricity began just over a hundred years ago.

History of the world electric power industry

Electric power industry is a strategic sector of the economic system of any state. The history of the emergence and development of energy efficiency dates back to the end of the 19th century. The forerunner of the emergence of industrial electricity generation was the discovery of fundamental laws about the nature and properties of electric current.

The starting point when the production and transmission of electricity arose is considered to be 1892. It was then that the first power plant was built in New York under the leadership of Thomas Edison. The station became a source of electric current for street lighting lamps. This was the first experience in converting thermal energy from coal combustion into electricity.

Since then, the era of mass construction of thermal power plants (TPPs) operating on solid fuel - thermal coal - has begun. With the development of the oil industry, huge reserves of fuel oil appeared, which were formed as a result of the refining of petroleum products. Technologies have been developed for obtaining a carrier of thermal energy (steam) from burning fuel oil.

Since the thirties of the last century, hydroelectric power plants (HPPs) have become widespread. Enterprises began to use the energy of falling water flows from rivers and reservoirs.

In the 70s, rapid construction of nuclear power plants (NPPs) began. At the same time, alternative sources of electricity began to be developed and implemented: wind turbines, solar panels, and alkaline-acid geostations. Mini installations have appeared that use heat to generate electricity as a result of chemical processes of decomposition of manure and household waste.

History of Russian electric power industry

A powerful impetus for the development of electrical energy production was the adoption by the young state of the USSR of the GOELRO plan in 1920. It was decided to build 10 power plants with a total capacity of 640 thousand kW over 15 years. However, by 1935, 40 state regional power plants (GRES) had been commissioned. A powerful base for the industrialization of Russia and the Union republics was created.

In the 1930s, mass construction of hydroelectric power stations (HPPs) began on the territory of the USSR. The rivers of Siberia were developed. The famous Dnieper Hydroelectric Power Station was built in Ukraine. In the post-war years, the state paid attention to the construction of hydroelectric power stations.

Important! The emergence of cheap electricity in Russia solved the problem of urban transport in large regional centers. Trams and trolleybuses not only became an economic incentive for the use of electricity in transport, but also brought a significant reduction in liquid fuel consumption. Cheap energy resources led to the appearance of electric locomotives on railways.

In the 70s, as a result of the global energy crisis, there was a sharp increase in oil prices. A nuclear energy development plan has begun to be implemented in Russia. Almost all republics of the Soviet Union began to build nuclear power plants. Today's Russia has become the leader in this regard. Today, there are 21 nuclear power plants operating on the territory of the Russian Federation.

Basic technological processes in the electric power industry

Electricity production in Russia is based on three pillars of the energy system. These are nuclear, thermal and hydropower.

Three types of electricity generation

Electric power industries

The list of industrial sources of electrical energy production consists of 4 energy sectors:

• atomic;
• thermal;
• hydropower;
• alternative.

Nuclear power

This branch of energy production is today the most effective way to generate electricity through a nuclear reaction. For this purpose, purified uranium is used. The heart of the station is the nuclear reactor.

Heat sources are fuel elements (fuel elements). They are thin, long zirconium tubes containing uranium tablets. They are combined into groups - fuel assembly (fuel assembly). They load the reactor vessel, in the body of which there are pipes with water. During the nuclear decay of uranium, heat is released, which heats the water in the primary circuit to 3200.

The steam flows to turbine blades, which rotate alternating current generators. Electricity enters the general energy system through transformers.

Note! Remembering the Chernobyl tragedy, scientists around the world are improving the safety system of nuclear power plants. The latest developments in nuclear energy ensure that nuclear power plants are almost 100% harmless.

Thermal energy

Thermal power plants operate on the principle of burning natural fuels: coal, gas and fuel oil. Water passing through pipelines through boilers is converted into steam and is subsequently supplied to the blades of generator turbines.

Additional Information. Over 4 years of operation of one group of fuel rods, such an amount of electricity is generated that the thermal power plant will need to burn 730 natural gas tanks, 600 coal cars or 900 oil railway tankers.

In addition, thermal power plants greatly worsen the environmental situation in the areas where they are located. Fuel combustion products heavily pollute the atmosphere. Only stations operating on gas turbine units meet the requirements of environmental cleanliness.

Hydropower

Examples of the effective use of hydropower are the Aswan, Sayano-Shushenskaya hydroelectric power stations, etc. The most environmentally friendly power plants that use the kinetic energy of water movement do not produce any harmful emissions into the environment. However, the mass construction of hydraulic structures is limited by a combination of circumstances. This is the presence of a certain amount of natural water flow, a feature of the terrain, and much more.

alternative energy

The scientific and technological revolution does not stop for a minute. Every day brings innovations in the production of electric current. Inquisitive minds are constantly busy searching for new technologies for generating electricity, which act as an alternative to traditional methods of generating electricity.

Mention should be made of wind generators, tidal sea stations and solar panels. Along with this, devices appeared that generate electric current using the heat of decomposition of household waste and livestock waste products. There are devices that use the temperature difference between different layers of soil, the alkaline and acidic environment of the soil at different levels. Alternative sources of electricity have one thing in common - this is the incomparability of the amount of energy generated with the amount of electricity that is obtained by traditional methods (nuclear power plants, thermal power plants and hydroelectric power plants).

Electrical energy transmission and distribution

Regardless of the design of power plants, their energy is supplied to the country’s unified energy system. The transmitted electricity enters distribution substations, and from there it reaches the consumers themselves. The transmission of electricity from producers is carried out by air through power lines. For short distances, current flows in a cable that is laid underground.

Electrical energy consumption

With the advent of new industrial facilities and the commissioning of residential complexes and civil buildings, electricity consumption is increasing every day. Almost every year, new power plants come into operation in Russia, or existing enterprises are replenished with new power units.

Types of activities in the electric power industry

Electric companies are engaged in the uninterrupted delivery of electricity to every consumer. In the energy sector, the employment level exceeds that of some leading sectors of the state's national economy.

Operational dispatch control

TAC plays a critical role in the redistribution of energy flows in an environment of changing consumption levels. Dispatch services are aimed at transmitting electric current from the manufacturer to the consumer in a trouble-free manner. In the event of any accidents or failures in power lines, the ODU performs the duties of the operational headquarters to quickly eliminate these shortcomings.

Energosbyt

Tariffs for payment for electricity consumption include costs for the profits of energy companies. The correctness and timeliness of payment for consumed services is monitored by the Energosbyt service. The financial support of the entire energy system of the country depends on it. Penalties are applied to non-payers, up to and including disconnecting the consumer's power supply.

The energy system is the circulatory system of a single organism of the state. Electricity production is a strategic area of ​​security for the existence and development of the country's economy.

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Electricity makes people's lives better, brighter and cleaner. But before it can travel along high-voltage power lines and then be distributed to homes and businesses, electrical energy must be generated by a power plant.

How is electricity generated?

In 1831, M. Faraday discovered that when a magnet rotates around a coil of wire, an electric current flows in the conductor. An electricity generator is a device that converts another form of energy into electrical energy. These units operate based on the interaction of electric and magnetic fields. Almost all of the power consumed is produced by generators that convert mechanical energy into electrical energy.

The production of electricity in the usual way is carried out by a generator with an electromagnet. It has a series of insulated coils of wire forming a stationary cylinder (stator). Inside the cylinder there is a rotating electromagnetic shaft (rotor). When the electromagnetic shaft rotates, an electric current arises in the stator coils, which is then transmitted through power lines to consumers.

In power plants, turbines are used as generators to produce electrical energy, which come in various types:

• steam;
• gas combustion turbines;
• water;
• wind.

In a turbogenerator, moving liquid or gas (steam) hits blades mounted on a shaft and rotates the shaft connected to the generator. Thus, the mechanical energy of water or gas is converted into electrical energy.

Interesting. Currently, 93% of the world's electricity comes from steam, gas and water turbines using biomass, coal, geothermal, nuclear energy, and natural gas.

Other types of devices that generate electricity:

• electrochemical batteries;
• fuel devices;
• solar photovoltaic cells;
• thermoelectric generators.

History of the electric power industry

Before the advent of electricity, people burned vegetable oil, wax candles, fat, kerosene, and gasified coal to illuminate houses, streets, and workshops. Electricity made it possible to have clean, safe, bright lighting, for which the first power plant was built. Thomas Edison launched it in lower Manhattan (New York) in 1882 and pushed aside the darkness forever, opening up a new world. The coal-fired Pearl Street Station became the prototype for the entire emerging energy industry. It consisted of six dynamo generators, each weighing 27 tons and producing 100 kW.

In Russia, the first power plants began to appear in the late 80s-90s of the 19th century in Moscow, St. Petersburg and Odessa. As electricity transmission developed, power plants were enlarged and moved closer to sources of raw materials. A powerful impetus to the production and use of electrical energy was given by the GOELRO plan adopted in 1920.

Fossil fuel stations

Fossil fuels are the remains of plant and animal life that have been subjected to high temperatures, high pressures over millions of years and come out in the form of carbons: peat, coal, oil and natural gas. Unlike electricity itself, fossil fuels can be stored in large quantities. Fossil fuel power plants are generally reliable and last for decades.

Disadvantages of thermal power plants:

1. Fuel combustion results in sulfur dioxide and nitrogen oxide pollution, requiring expensive treatment systems;
2. Wastewater from used steam can carry pollutants into water bodies;
3. Current difficulties are large amounts of carbon dioxide and coal ash.

Important! The extraction and transportation of fossil resources creates environmental problems that can lead to catastrophic consequences for ecosystems.

The efficiency of thermal power plants is below 50%. To increase it, thermal power plants are used, in which the thermal energy of the used steam is used for heating and supplying hot water. At the same time, efficiency increases to 70%.

Gas turbines and biomass plants

Some natural gas units can produce electricity without steam. They use turbines very similar to jet airplane turbines. However, instead of jet fuel, they burn natural gas to power a generator. Such installations are convenient because they can be brought online quickly in response to temporary surges in electricity demand.

There are units whose operation is based on the combustion of biomass. This term applies to wood waste or other renewable plant materials. For example, the Okeelanta plant in Florida burns grass waste from sugar cane processing for part of the year and wood waste for the remainder of the year.

Hydroelectric power stations

There are two types of hydroelectric power plants operating in the world. The first type takes energy from a fast-moving stream to turn a turbine. Water flow in most rivers can vary widely depending on rainfall, and there are several suitable locations along the river course for the construction of power plants.

Most hydroelectric power plants use a reservoir to compensate for periods of drought and increase water pressure in the turbines. These artificial reservoirs cover large areas, creating picturesque features. The massive dams required are also useful for flood control. In the past, few doubted that the benefits of their construction exceeded the costs.

However, now the point of view has changed:

1. Huge areas of land for reservoirs are being lost;
2. The dams have displaced people and destroyed wildlife habitat and archaeological sites.

Some costs can be offset, for example, by building fish passages in the dam. However, others remain, and the construction of hydroelectric dams is widely protested by local residents.

The second type of hydroelectric power station is pumped storage power plant, or pumped storage power plant. The units operate in two modes: pumping and generator. Pumped storage power plants use periods of low demand (night) to pump water into a reservoir. When demand increases, some of this water is sent to hydro turbines to generate electricity. These stations are economically profitable because they use cheap electricity for pumping and generate expensive electricity.

NPP

Despite some important technical differences, nuclear power plants are thermal and produce electricity in much the same way as fossil fuel plants. The difference is that they generate steam using the heat of atomic fission rather than from burning coal, oil or gas. Then the steam works in the same way as in thermal units.

Features of the nuclear power plant:

1. Nuclear plants do not use much fuel and are rarely refueled, unlike coal plants, which are loaded with fuel by railcar;
2. Greenhouse gases and harmful emissions are minimal when properly operated, which makes nuclear power attractive to people concerned about air quality;
3. The wastewater is hotter, large cooling towers are designed to solve this problem.

The emerging desire for nuclear energy faltered in the face of social problems related to environmental and economic safety issues. Creating better safety mechanisms increases construction and operating costs. The problem of disposal of spent nuclear fuel and contaminated accessories, which can remain dangerous for thousands of years, has not yet been resolved.

Important! The Three Mile Island accident in 1979 and Chernobyl in 1986 were serious disasters. Ongoing economic problems have made nuclear power plants less attractive. Despite producing 16% of the world's electricity, the future of nuclear power is uncertain and hotly debated.

Wind energy

Wind farms do not require water storage and do not pollute the air, which carries much less energy than water. Therefore, it is necessary to build either very large units or many small ones. Construction costs can be high.

Additionally, there are few places where the wind blows predictably. Turbines are designed using a special gear to spin the rotor at a constant speed.

Alternative energies

1. Geothermal. A clear example of the heat available underground is seen when geysers erupt. The disadvantage of geothermal power plants is the need for construction in areas with seismic hazard;
2. Solar. Solar panels themselves are a generator. They take advantage of the ability to convert solar radiation into electricity. Until recently, solar cells were expensive, increasing their efficiency is also a difficult task;

1. Fuel cells. They are used, in particular, in spacecraft. There they chemically combine hydrogen and oxygen to form water and generate electricity. So far, such installations are expensive and have not found widespread use. Although a central fuel cell power plant has already been created in Japan.

Electricity usage

1. Two thirds of the energy generated goes to industry;
2. The second main direction is the use of electricity in transport. Electric transport: railways, trams, trolleybuses, metro operate on direct and alternating current. Recently, more and more electric vehicles are appearing, for which a network of gas stations is being built;
3. The household sector consumes the least amount of electricity: residential buildings, shops, offices, educational institutions, hospitals, etc.

As power generation technologies improve and environmental safety improves, the very concept of building large centralized power plants is being called into question. In most cases, it is no longer economically viable to heat houses from the center. Further developments in fuel cells and solar panels could completely change the landscape of electricity generation and transmission. This opportunity is all the more attractive given the cost and objections associated with the construction of large power plants and transmission lines.

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K category: Electric installation work

Electrical energy production

Electrical energy (electricity) is the most advanced type of energy and is used in all areas and branches of material production. Its advantages include the possibility of transmission over long distances and conversion into other types of energy (mechanical, thermal, chemical, light, etc.).

Electrical energy is generated at special enterprises - power stations that convert other types of energy into electrical energy: chemical, fuel, water, wind, solar, nuclear energy.

The ability to transmit electricity over long distances makes it possible to build power plants near fuel locations or on high-water rivers, which is more economical than transporting large quantities of fuel to power plants located near electricity consumers.

Depending on the type of energy used, power plants are divided into thermal, hydraulic, and nuclear. Power plants using wind energy and solar heat are still low-power sources of electricity that have no industrial significance.

Thermal power plants use thermal energy obtained by burning solid fuel (coal, peat, oil shale), liquid (fuel oil) and gaseous (natural gas, and at metallurgical plants - blast furnace and coke oven gas) in boiler furnaces.

Thermal energy is converted into mechanical energy by the rotation of the turbine, which is converted into electrical energy in a generator connected to the turbine. The generator becomes a source of electricity. Thermal power plants are distinguished by the type of primary engine: steam turbine, steam engine, internal combustion engine, locomobile, gas turbine. In addition, steam turbine power plants are divided into condensing and heating plants. Condensing stations supply consumers only with electrical energy. The exhaust steam goes through a cooling cycle and, turning into condensate, is again supplied to the boiler.

The supply of heat and electricity to consumers is carried out by heating stations called combined heat and power plants (CHP). At these stations, thermal energy is only partially converted into electrical energy, and is mainly spent on supplying industrial enterprises and other consumers located in close proximity to power plants with steam and hot water.

Hydroelectric power plants (HPPs) are built on rivers, which are an inexhaustible source of energy for power plants. They flow from highlands to lowlands and are therefore capable of performing mechanical work. Hydroelectric power stations are built on mountain rivers using natural water pressure. On lowland rivers, pressure is created artificially by the construction of dams, due to the difference in water levels on both sides of the dam. The primary engines in hydroelectric power plants are hydraulic turbines, in which the energy of the water flow is converted into mechanical energy.

Water rotates the impeller of the hydraulic turbine and the generator, while the mechanical energy of the hydraulic turbine is converted into electrical energy generated by the generator. The construction of a hydroelectric power station solves, in addition to the problem of generating electricity, also a complex of other problems of national economic importance - improving the navigation of rivers, irrigation and watering of arid lands, improving water supply to cities and industrial enterprises.

Nuclear power plants (NPPs) are classified as thermal steam turbine stations that do not operate on organic fuel, but use as an energy source the heat obtained during the fission of the nuclei of nuclear fuel (fuel) atoms - uranium or plutonium. At nuclear power plants, the role of boiler units is performed by nuclear reactors and steam generators.

Electricity supply to consumers is carried out primarily from electrical networks connecting a number of power plants. Parallel operation of power plants on a common electrical network ensures rational distribution of the load between power plants, the most economical generation of electricity, better use of the installed capacity of the stations, increased reliability of power supply to consumers and the supply of electricity to them with normal quality indicators in frequency and voltage.

The need for unification is caused by the unequal load of power plants. Consumer demand for electricity changes dramatically not only during the day, but also at different times of the year. In winter, electricity consumption for lighting increases. In agriculture, electricity is needed in large quantities in the summer for field work and irrigation.

The difference in the degree of load of stations is especially noticeable when the areas of electricity consumption are significantly distant from each other in the direction from east to west, which is explained by the different timing of the hours of morning and evening maximum load. To ensure reliable power supply to consumers and to make fuller use of the power of power plants operating in different modes, they are combined into energy or electrical systems using high-voltage electrical networks.

The set of power plants, power transmission lines and heating networks, as well as receivers of electrical and thermal energy, connected into one by the commonality of the regime and the continuity of the process of production and consumption of electrical and thermal energy, is called an energy system (energy system). An electrical system consisting of substations and power lines of various voltages is part of the power grid.

The energy systems of individual regions, in turn, are interconnected for parallel operation and form large systems, for example, the Unified Energy System (UES) of the European part of the USSR, the integrated systems of Siberia, Kazakhstan, Central Asia, etc.

Combined heat and power plants and factory power plants are usually connected to the electrical network of the nearest power system via generator voltage lines of 6 and 10 kV or higher voltage lines (35 kV and above) through transformer substations. The energy generated by powerful regional power plants is transferred to the power grid to supply consumers via high voltage lines (110 kV and above).