Production, transmission and distribution of electrical energy. Production, transmission and use of electrical energy

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in physics

on the topic: "Production, transmission and consumption of electricity"

Performed:

Student 11A

Khodakova Yulia

Teacher:

Dubinina Marina Nikolaevna

1. Electricity production

Electricity is produced at power plants, often using electromechanical induction generators. There are 2 main types of power plants - thermal power plants (TPP) and hydroelectric power plants (HPP) - differing in the nature of the engines that rotate the rotors of the generators.

The source of energy at thermal power plants is fuel: fuel oil, oil shale, oil, coal dust. The rotors of electric generators are driven by steam and gas turbines or internal combustion engines (ICE).

As is known, the efficiency of heat engines increases with increasing initial temperature of the working fluid. Therefore, the steam that enters the turbine is brought to about 550 °C at a pressure of about 25 MPa. The efficiency of thermal power plants reaches 40%.

At thermal power plants (CHP), most of the energy from waste steam is used in industrial enterprises and for domestic needs. The efficiency of thermal power plants can reach 60-70%.

At hydroelectric power stations, the potential energy of water is used to rotate the rotors of generators. The rotors are driven by hydraulic turbines.

The power of the station depends on the difference in water levels that are created by the dam (pressure), and on the mass of water that passes through the turbine in 1 second (water flow).

Part of the electricity consumed in Russia (approximately 10%) is produced at nuclear power plants (NPPs).

2. Electricity transmission

Basically, this process is accompanied by significant losses that are associated with the heating of power line wires by current. According to the Joule-Lenz law, the energy spent on heating the wires is proportional to the square of the current strength and the resistance of the line, so if the line is long, transmitting electricity can become economically unprofitable. Therefore, it is necessary to reduce the current, which, for a given transmitted power, leads to the need to increase the voltage. The longer the power line, the more profitable it is to use higher voltages (on some, the voltage reaches 500 kV). Alternating current generators produce voltages that cannot exceed 20 kV (which is due to the properties of the insulating materials used).

Therefore, step-up transformers are installed at power plants, which increase the voltage and reduce the current by the same amount. To supply electricity consumers with the required (low) voltage, step-down transformers are installed at the ends of the power transmission line. Voltage reduction is usually done in stages.

3. Electricity use

Electrical energy is used almost everywhere. Of course, most of the electricity produced comes from industry. In addition, transport will be a major consumer.

Many railway lines have long switched to electric traction. Lighting of homes, city streets, industrial and domestic needs of villages and villages - all this is also a large consumer of electricity.

A huge part of the generated electricity is converted into mechanical energy. All mechanisms used in industry are driven by electric motors. There are plenty of electricity consumers, and they are found everywhere.

And electricity is produced only in a few places. The question arises about the transmission of electricity, and over long distances. When transmitting over long distances, there is a lot of power loss. Mainly, these are losses due to heating of electrical wires.

According to the Joule-Lenz law, the energy spent on heating is calculated by the formula:

electrical energy atomic thermal

Since it is almost impossible to reduce the resistance to an acceptable level, you have to reduce the current. To do this, increase the voltage. Typically, stations have step-up generators, and at the end of the transmission lines there are step-down transformers. And from them the energy is distributed to consumers.

The demand for electrical energy is constantly increasing. In order to meet demands for increased consumption, there are two ways:

1. Construction of new power plants

2. Use of advanced technologies.

Efficient use of electricity

The first method requires the expenditure of a large number of construction and financial resources. It takes several years to build one power plant. In addition, for example, thermal power plants consume a lot of non-renewable natural resources and harm the environment.

Using advanced technologies is a very correct solution to this problem. In addition, it is necessary to avoid wasting energy and reduce inefficient use to a minimum.

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Page 1

Introduction.

The birth of energy occurred several million years ago, when people learned to use fire. Fire gave them warmth and light, was a source of inspiration and optimism, a weapon against enemies and wild animals, a healing agent, an assistant in agriculture, a food preservative, a technological tool, etc.

The wonderful myth of Prometheus, who gave fire to people, appeared in Ancient Greece much later, after many parts of the world had mastered methods of quite sophisticated handling of fire, its production and extinguishing, preservation of fire and rational use of fuel.

For many years, fire was maintained by burning plant energy sources (wood, shrubs, reeds, grass, dry algae, etc.), and then it was discovered that it was possible to use fossil substances to maintain fire: coal, oil, shale, peat.

Today, energy remains the main component of human life. It makes it possible to create various materials and is one of the main factors in the development of new technologies. Simply put, without mastering various types of energy, a person is not able to fully exist.

Power generation.

Types of power plants.

Thermal power plant (TPP), a power plant that generates electrical energy as a result of the conversion of thermal energy released during the combustion of organic fuel. The first thermal power plants appeared at the end of the 19th century and became widespread. In the mid-70s of the 20th century, thermal power plants were the main type of power plants.

In thermal power plants, the chemical energy of the fuel is converted first into mechanical energy and then into electrical energy. The fuel for such a power plant can be coal, peat, gas, oil shale, and fuel oil.

Thermal power plants are divided into condensing power plants (CHPs), designed to generate only electrical energy, and combined heat and power plants (CHPs), which produce, in addition to electricity, thermal energy in the form of hot water and steam. Large CPPs of regional significance are called state district power plants (SDPPs).

The simplest schematic diagram of a coal-fired IES is shown in the figure. Coal is fed into the fuel bunker 1, and from it into the crushing unit 2, where it turns into dust. Coal dust enters the furnace of a steam generator (steam boiler) 3, which has a system of tubes in which chemically purified water, called feed water, circulates. In the boiler, the water is heated, evaporated, and the resulting saturated steam is brought to a temperature of 400-650 °C and, under a pressure of 3-24 MPa, enters steam turbine 4 through a steam line. Steam parameters depend on the power of the units.

Thermal condensing power plants have low efficiency (30-40%), since most of the energy is lost with flue gases and condenser cooling water. It is advantageous to build CPPs in close proximity to fuel production sites. In this case, electricity consumers may be located at a considerable distance from the station.

A combined heat and power plant differs from a condensing station by having a special heating turbine installed on it with steam extraction. At a thermal power plant, one part of the steam is completely used in the turbine to generate electricity in the generator 5 and then enters the condenser 6, and the other, having a higher temperature and pressure, is taken from the intermediate stage of the turbine and is used for heat supply. The condensate is supplied by pump 7 through the deaerator 8 and then by the feed pump 9 to the steam generator. The amount of steam taken depends on the thermal energy needs of enterprises.

The efficiency of thermal power plants reaches 60-70%. Such stations are usually built near consumers - industrial enterprises or residential areas. Most often they run on imported fuel.

Thermal stations with gas turbine (GTPP), combined cycle (CGPP) and diesel plants have become significantly less widespread.

Gas or liquid fuel is burned in the combustion chamber of a gas turbine power plant; combustion products with a temperature of 750-900 ºС enter a gas turbine that rotates an electric generator. The efficiency of such thermal power plants is usually 26-28%, the power is up to several hundred MW. GTPPs are usually used to cover electrical load peaks. The efficiency of PGES can reach 42 - 43%.

The most economical are large thermal steam turbine power plants (abbreviated TPP). Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are consumed. In a steam boiler, over 90% of the energy released by the fuel is transferred to steam. In the turbine, the kinetic energy of the steam jets is transferred to the rotor. The turbine shaft is rigidly connected to the generator shaft.

Modern steam turbines for thermal power plants are very advanced, high-speed, highly economical machines with a long service life. Their power in a single-shaft version reaches 1 million 200 thousand kW, and this is not the limit. Such machines are always multi-stage, that is, they usually have several dozen disks with working blades and the same number, in front of each disk, of groups of nozzles through which a stream of steam flows. The pressure and temperature of the steam gradually decrease.

It is known from a physics course that the efficiency of heat engines increases with increasing initial temperature of the working fluid. Therefore, the steam entering the turbine is brought to high parameters: temperature - almost 550 ° C and pressure - up to 25 MPa. The efficiency of thermal power plants reaches 40%. Most of the energy is lost along with the hot exhaust steam.

Hydroelectric station (HPP), a complex of structures and equipment through which the energy of water flow is converted into electrical energy. A hydroelectric power station consists of a sequential chain of hydraulic structures that provide the necessary concentration of water flow and the creation of pressure, and energy equipment that converts the energy of water moving under pressure into mechanical rotational energy, which, in turn, is converted into electrical energy.

Khokhlova Kristina

Presentation on the topic "Production, transmission and use of electrical energy"

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Presentation Production, transmission and use of electrical energy Kristina Khokhlova, 11th grade, Municipal Educational Institution-Secondary School No. 64

Presentation plan Electricity generation Types of power plants Alternative energy sources Electricity transmission Electricity use

There are several types of power plants: Types of power plants TPP HPP NPP

Thermal power plant (TPP), a power plant that generates electrical energy as a result of the conversion of thermal energy released during the combustion of fossil fuels. In thermal power plants, the chemical energy of the fuel is converted first into mechanical energy and then into electrical energy. The fuel for such a power plant can be coal, peat, gas, oil shale, and fuel oil. The most economical are large thermal steam turbine power plants. Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are consumed. In a steam boiler, over 90% of the energy released by the fuel is transferred to steam. In the turbine, the kinetic energy of the steam jets is transferred to the rotor. The turbine shaft is rigidly connected to the generator shaft. TPP

TPPs TPPs are divided into: Condensing power plants (CHES) They are designed to generate only electrical energy. Large CPPs of regional significance are called state district power plants (SDPPs). combined heat and power plants (CHPs) that produce, in addition to electricity, thermal energy in the form of hot water and steam.

Hydroelectric station (HPP), a complex of structures and equipment through which the energy of water flow is converted into electrical energy. A hydroelectric power station consists of a sequential chain of hydraulic structures that provide the necessary concentration of water flow and the creation of pressure, and energy equipment that converts the energy of water moving under pressure into mechanical rotational energy, which, in turn, is converted into electrical energy. The pressure of a hydroelectric power station is created by the concentration of the fall of the river in the area being used by a dam, or diversion, or a dam and diversion together. hydroelectric power station

Power of hydroelectric power stations Hydroelectric power stations are also divided into: The power of hydroelectric power stations depends on the pressure, water flow used in hydraulic turbines, and the efficiency of the hydraulic unit. For a number of reasons (due to, for example, seasonal changes in the water level in reservoirs, fluctuations in the load of the power system, repairs of hydraulic units or hydraulic structures, etc.), the pressure and flow of water continuously change, and, in addition, the flow changes when regulating the power of a hydroelectric power station. high-pressure (over 60 m) medium-pressure (from 25 to 60 m) low-pressure (from 3 to 25 m) Medium (up to 25 MW) Powerful (over 25 MW) Small (up to 5 MW)

A special place among hydroelectric power plants is occupied by: Pumped storage power plants (PSPPs) The ability of PSPPs to accumulate energy is based on the fact that free electrical energy in the power system for a certain period of time is used by pumped storage power plants, which, operating in pump mode, pump water from the reservoir into the upper storage pool. During peak load periods, the accumulated energy is returned to the power system. Tidal power plants (TPPs) TPPs convert the energy of sea tides into electricity. The electricity of tidal hydroelectric power stations, due to some features associated with the periodic nature of the ebb and flow of tides, can be used in energy systems only in conjunction with the energy of regulating power plants, which make up for the power failures of tidal power stations within days or months.

The heat that is released in the reactor as a result of the chain reaction of fission of the nuclei of some heavy elements is then converted into electricity in the same way as in conventional thermal power plants (TPPs). Unlike thermal power plants that run on fossil fuels, nuclear power plants run on nuclear fuel (based on 233U, 235U, 239Pu). It has been established that the world's energy resources of nuclear fuel (uranium, plutonium, etc.) significantly exceed the energy resources of natural reserves of organic fuel (oil, coal, natural gas, etc.). In addition, it is necessary to take into account the ever-increasing volume of coal and oil consumption for technological purposes in the global chemical industry, which is becoming a serious competitor to thermal power plants. NPP

Nuclear power plants Most often, 4 types of thermal neutron reactors are used at nuclear power plants: graphite-water reactors with a water coolant and a graphite moderator, heavy-water with a water coolant and heavy water as a moderator, water-water with ordinary water as a moderator and coolant, graffito-gas with a gas coolant and a graphite moderator.

The choice of the predominantly used type of reactor is determined mainly by the accumulated experience in the reactor carrier, as well as the availability of the necessary industrial equipment, raw material reserves, etc. The reactor and its servicing systems include: the reactor itself with biological protection, heat exchangers, pumps or gas-blowing units that circulate coolant, pipelines and circuit fittings, devices for reloading nuclear fuel, special ventilation systems, emergency cooling, etc. To protect nuclear power plant personnel from radiation exposure, the reactor is surrounded by biological shielding, the main materials for which are concrete, water, and serpentine sand. The reactor circuit equipment must be completely sealed. NPP

Alternative energy sources. Solar energy Solar energy is one of the most material-intensive types of energy production. Large-scale use of solar energy entails a gigantic increase in the need for materials, and, consequently, in labor resources for the extraction of raw materials, their enrichment, obtaining materials, manufacturing heliostats, collectors, other equipment, and their transportation. Wind energy The energy of moving air masses is enormous. The reserves of wind energy are more than a hundred times greater than the hydropower reserves of all the rivers on the planet. Winds blow constantly and everywhere on earth. Climatic conditions allow the development of wind energy over a vast territory. Through the efforts of scientists and engineers, a wide variety of designs of modern wind turbines have been created. Earth energy Earth energy is suitable not only for heating premises, as is the case in Iceland, but also for generating electricity. Power plants using hot underground springs have been operating for a long time. The first such power plant, still very low-power, was built in 1904 in the small Italian town of Larderello. Gradually, the power of the power plant grew, more and more new units were put into operation, new sources of hot water were used, and today the power of the station has already reached an impressive value of 360 thousand kilowatts.

Solar energy Air energy Earth energy

Electricity transmission Electricity consumers are everywhere. It is produced in relatively few places close to sources of fuel and hydro resources. Therefore, there is a need to transmit electricity over distances sometimes reaching hundreds of kilometers. But transmitting electricity over long distances is associated with noticeable losses. The fact is that as current flows through power lines, it heats them up. In accordance with the Joule-Lenz law, the energy spent on heating the line wires is determined by the formula: Q= I 2 Rt where R is the line resistance. With a large line length, energy transmission may become generally unprofitable. To reduce losses, you can increase the cross-sectional area of ​​the wires. But when R decreases by 100 times, the mass must also be increased by 100 times. Such consumption of non-ferrous metal should not be allowed. Therefore, energy losses in the line are reduced in another way: by reducing the current in the line. For example, reducing the current by 10 times reduces the amount of heat released in the conductors by 100 times, i.e., the same effect is achieved as from making the wire a hundred times heavier. That's why step-up transformers are installed at large power plants. The transformer increases the voltage in the line by the same amount as it decreases the current. The power losses are small. Electric power stations in a number of regions of the country are connected by high-voltage transmission lines, forming a common power grid to which consumers are connected. Such an association is called a power system. The power system ensures uninterrupted supply of energy to consumers regardless of their location.

The use of electricity in various fields of science Science directly influences the development of energy and the scope of application of electricity. About 80% of the GDP growth in developed countries is achieved through technical innovation, the bulk of which is related to the use of electricity. Everything new in industry, agriculture and everyday life comes to us thanks to new developments in various branches of science. Most scientific developments begin with theoretical calculations. But if in the 19th century these calculations were made using pen and paper, then in the age of the STR (scientific and technological revolution) all theoretical calculations, selection and analysis of scientific data, and even linguistic analysis of literary works are done using computers (electronic computers), which operate on electrical energy, which is most convenient for transmitting it over a distance and using it. But if initially computers were used for scientific calculations, now computers have come from science to life. Electronization and automation of production are the most important consequences of the “second industrial” or “microelectronic” revolution in the economies of developed countries. Science in the field of communications and communications is developing very rapidly. Satellite communications are no longer used only as a means of international communication, but also in everyday life - satellite antennas not uncommon in our city. New means of communication, for example, fiber technology, can significantly reduce energy losses in the process of transmitting signals over long distances. Completely new means of obtaining information, storing it, processing it and transmitting it, together forming a complex information structure, have been created.

Use of electricity in production Modern society cannot be imagined without the electrification of production activities. Already at the end of the 80s, more than 1/3 of all energy consumption in the world was carried out in the form of electrical energy. By the beginning of the next century, this share may increase to 1/2. This increase in electricity consumption is primarily associated with an increase in its consumption in industry. The bulk of industrial enterprises operate on electrical energy. High electricity consumption is typical for energy-intensive industries such as metallurgy, aluminum and mechanical engineering.

Use of electricity in everyday life Electricity in everyday life is an integral assistant. Every day we deal with her, and, probably, we can no longer imagine our life without her. Remember the last time your lights were turned off, that is, there was no electricity coming to your house, remember how you swore that you didn’t have time to do anything and you needed light, you needed a TV, a kettle and a bunch of other electrical appliances. After all, if we were to lose power forever, we would simply return to those ancient times when food was cooked over fires and we lived in cold wigwams. A whole poem can be dedicated to the importance of electricity in our lives, it is so important in our lives and we are so accustomed to it. Although we no longer notice that it is coming into our homes, when it is turned off, it becomes very uncomfortable.

Thank you for your attention

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, in addition to the problem of generating electricity, also solves 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).

>> Production and use of electrical energy

§ 39 PRODUCTION and USE OF ELECTRIC ENERGY

Nowadays, the level of energy production and consumption is one of the most important indicators of the development of industrial production forces. The leading role here is played by electricity - the most universal and convenient form of energy. If energy consumption in the world doubles in about 25 years, then an increase in electricity consumption by 2 times occurs on average in 10 years. This means that more and more energy-consuming processes are being converted to electricity.

Power generation. Electricity is produced at large and small power plants mainly using electromechanical induction generators. There are two main types of power plants: thermal and hydroelectric. These power plants differ in the engines that rotate the generator rotors.

At thermal power plants, the source of energy is fuel: coal, gas, oil, fuel oil, oil shale. The rotors of electric generators are driven by steam and gas turbines or internal combustion engines. The most economical are large thermal steam turbine power plants (abbreviated as TPP). Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are consumed. In a steam boiler, over 90% of the energy released by the fuel is transferred to steam. In the turbine, the kinetic energy of the steam jets is transferred to the rotor. The turbine shaft is rigidly connected to the generator shaft. Steam turbogenerators are very fast: the rotor speed is several thousand per minute.

From the 10th grade physics course it is known that the efficiency of heat engines increases with increasing temperature of the heater and, accordingly, the initial temperature of the working fluid (steam, gas). Therefore, the steam entering the turbine is brought to high parameters: temperature - almost 550 ° C and pressure - up to 25 MPa. The efficiency of thermal power plants reaches 40%. Most of the energy is lost along with the hot exhaust steam. Energy transformations are shown in the diagram shown in Figure 5.5.

Thermal power plants - the so-called combined heat and power plants (CHPs) - allow a significant part of the energy from waste steam to be used in industrial enterprises and for domestic needs (for heating and hot water supply). As a result, the efficiency of the thermal power plant reaches 60-70%. Currently in Russia, thermal power plants provide about 40% of all electricity and supply hundreds of cities with electricity and heat.

Hydroelectric power plants (HPPs) use the potential energy of water to rotate generator rotors. The rotors of electric generators are driven by hydraulic turbines. The power of such a station depends on the difference in water levels created by the dam (pressure) and on the mass of water passing through the turbine every second (water flow). Energy transformations are shown in the diagram shown in Figure 5.6.

Hydroelectric power plants provide about 20% of all electricity generated in our country.

Nuclear power plants (NPPs) play a significant role in the energy sector. Currently, nuclear power plants in Russia provide about 10% of electricity.

Electricity use. 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 power plants for industrial and domestic needs. Everyone knows about the use of electricity for lighting homes and in household electrical appliances.

Most of the electricity used is now converted into mechanical energy. Almost all machinery in industry is driven by electric motors. They are convenient, compact, and allow production automation.

About a third of the electricity consumed by industry is used for technological purposes (electric welding, electric heating and melting of metals, electrolysis, etc.).

Modern civilization is unthinkable without the widespread use of electricity. A disruption in the power supply to a large city during an accident paralyzes his life.

1. Give examples of machines and mechanisms that would not use electric current at all!
2. Have you been near an electric current generator at a distance not exceeding 100 m!
3. What would the residents of a big city lose in the event of an electrical network failure!

Myakishev G. Ya., Physics. 11th grade: educational. for general education institutions: basic and profile. levels / G. Ya. Myakishev, B. V. Bukhovtsev, V. M. Charugin; edited by V. I. Nikolaeva, N. A. Parfentieva. - 17th ed., revised. and additional - M.: Education, 2008. - 399 p.: ill.

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