Abstract of the lesson "production and use of electrical energy". Production, transmission and use of electrical energy

abstract

in physics

on the topic "Production, transmission and use of electricity"

11th grade A students

MOU school number 85

Catherine.

Teacher:

2003

Abstract plan.

Introduction.

1. Power generation.

1. types of power plants.

2. alternative energy sources.

2. Electricity transmission.

transformers.

Introduction.

The beautiful myth of Prometheus, who gave people fire, appeared in Ancient Greece much later than, in many parts of the world, methods of rather sophisticated handling of fire, its production and extinguishment, fire conservation and rational use of fuel were mastered.

For many years, the 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 the fire: coal, oil, shale, peat.

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

Power generation.

Types of power plants.

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

Thermal power plants are divided into condensation(IES), designed to generate only electrical energy, and combined heat and power plants(CHP), producing in addition to electricity thermal energy as hot water and couple. Large IESs of district significance are called state district power plants (GRES).

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 plant 2, where it turns into dust. Coal dust enters the furnace of the steam generator (steam boiler) 3, which has a system of pipes in which chemically purified water, called feed water, circulates. In the boiler, the water heats up, evaporates, and the resulting saturated steam is brought to a temperature of 400-650 ° C and, under a pressure of 3-24 MPa, enters the steam turbine 4 through the steam pipeline. The steam parameters depend on the power of the units.

Thermal condensing power plants have a low efficiency (30-40%), since most of the energy is lost with flue gases and condenser cooling water. It is advantageous to build IES in the immediate vicinity of fuel extraction sites. At the same time, consumers of electricity can be located at a considerable distance from the station.

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

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

Significantly less widespread thermal stations from gas turbine(GTPS), steam-gas(PGES) and diesel plants.

Gas or liquid fuel is burned in the GTPP combustion chamber; combustion products with a temperature of 750-900 ºС enter the gas turbine that rotates the 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 SGPP can reach 42 - 43%.

The most economical are large thermal steam turbine power plants (TPPs for short). Most thermal power plants in our country use coal dust as fuel. It takes several hundred grams of coal to generate 1 kWh of electricity. 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 jet of steam flows. The steam pressure and temperature are gradually reduced.

From the course of physics it is known that the efficiency of heat engines increases with an increase in the initial temperature of the working fluid. Therefore, the steam entering the turbine is brought to high parameters: the temperature is almost up to 550 ° C and the pressure is up to 25 MPa. The efficiency of TPP 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 the water flow is converted into electrical energy. HPP consists of a series circuit hydraulic structures, providing the necessary concentration of water flow and the creation of pressure, and power equipment that converts the energy of water moving under pressure into mechanical energy of rotation, which, in turn, is converted into electrical energy.

The head of the hydroelectric power station is created by the concentration of the fall of the river in the used section by the dam, or derivation, or dam and derivation together. The main power equipment of the HPP is located in the HPP building: in the engine room of the power plant - hydraulic units, auxiliary equipment, automatic control and monitoring devices; in the central control post - the operator-dispatcher console or hydroelectric power plant operator. Boosting transformer substation located both inside the power plant building and in separate buildings or in open areas. Distribution devices often located in an open area. The power plant building can be divided into sections with one or more units and auxiliary equipment, separated from adjacent parts of the building. At the building of the HPP or inside it, an assembly site is created for the assembly and repair of various equipment and for auxiliary maintenance operations of the HPP.

By installed capacity(in MW) distinguish between hydroelectric power stations powerful(St. 250), medium(up to 25) and small(up to 5). The power of the hydroelectric power station depends on the pressure (the difference between the levels of the upstream and downstream ), the flow rate of water 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, variability in the load of the power system, repair of hydroelectric units or hydraulic structures, etc.), the pressure and flow of water are constantly changing, and, in addition, the flow changes when regulating the power of the HPP. There are annual, weekly and daily cycles of the HPP operation mode.

According to the maximum used pressure, HPPs are divided into high-pressure(over 60 m), medium pressure(from 25 to 60 m) And low-pressure(from 3 to 25 m). On flat rivers, the pressure rarely exceeds 100 m, in mountainous conditions, through the dam, it is possible to create pressures up to 300 m and more, and with the help of derivation - up to 1500 m. The subdivision of the hydroelectric power station according to the pressure used is approximate, conditional.

According to the scheme of use of water resources and the concentration of pressure, HPPs are usually divided into channel, near-dam, diversion with pressure and non-pressure derivation, mixed, pumped storage And tidal.

In run-of-river and near-dam HPPs, the water pressure is created by a dam that blocks the river and raises the water level in the upstream. At the same time, some flooding of the river valley is inevitable. Run-of-river and near-dam hydroelectric power stations are built both on low-lying high-water rivers and on mountain rivers, in narrow compressed valleys. Run-of-river HPPs are characterized by heads up to 30-40 m.

At higher pressures, it turns out to be impractical to transfer hydrostatic water pressure to the power plant building. In this case, the type dam The hydroelectric power station, in which the pressure front is blocked by a dam throughout its entire length, and the building of the hydroelectric power station is located behind the dam, adjoins the downstream.

Another kind of layout near the dam The hydroelectric power station corresponds to mountainous conditions with relatively low river flow rates.

IN derivational Hydroelectric concentration of the fall of the river is created through derivation; water at the beginning of the used section of the river is diverted from the river channel by a conduit, with a slope significantly less than the average slope of the river in this section and with straightening of the bends and turns of the channel. The end of the derivation is brought to the location of the HPP building. Waste water is either returned to the river or fed to the next diversion HPP. Derivation is beneficial when the slope of the river is high.

Special place among HPPs occupy pumped storage power plants(PSPP) and tidal power plants(PES). The construction of a pumped storage power plant is due to the growing demand for peak power in large energy systems, which determines the generating capacity required to cover peak loads. The ability of a pumped storage power plant to accumulate energy is based on the fact that free energy in the energy system in a certain period of time Electric Energy is used by pumped storage power plants, which, operating in pump mode, pump water from the reservoir into the upper storage pool. During load peaks, the accumulated energy returns to the power system (water from the upper pool enters penstock and rotates hydraulic units operating in the current generator mode).

PES convert the energy of sea tides into electrical energy. The electric power of tidal hydroelectric power plants, due to some features associated with the periodic nature of the tides, can only be used in power systems in conjunction with the energy of regulating power plants, which compensate for power failures of tidal power plants during the day or months.

The most important feature of hydropower resources in comparison with fuel and energy resources is their continuous renewal. The lack of need for fuel for HPPs determines the low cost of electricity generated at HPPs. Therefore, the construction of hydroelectric power stations, despite significant, specific capital investments per 1 kW installed capacity and long construction time, was and is of great importance, especially when it is associated with the location of electrically intensive industries.

Nuclear power plant (NPP), a power plant in which atomic (nuclear) energy is converted into electrical energy. The power generator at a nuclear power plant is a nuclear reactor. The heat released in the reactor as a result of chain reaction nuclear fission of some heavy elements, then, just as in conventional thermal power plants (TPPs), it is converted into electricity. Unlike thermal power plants operating on fossil fuels, nuclear power plants operate on nuclear fuel(based on 233 U, 235 U, 239 Pu). It has been established that the world's energy resources of nuclear fuel (uranium, plutonium, etc.) significantly exceed the energy resources natural resources organic, fuel (oil, coal, natural gas, etc.). This opens up broad prospects for meeting the rapidly growing demand for fuel. In addition, it is necessary to take into account the ever-increasing volume of consumption of coal and oil for technological purposes of the world economy. chemical industry, which is becoming a serious competitor to thermal power plants. Despite the discovery of new deposits of organic fuel and the improvement of methods for its production, the world tends to relative increase in its cost. This creates the most difficult conditions for countries with limited reserves of fossil fuels. There is an obvious need for the rapid development of nuclear energy, which already occupies a prominent place in the energy balance of a number of industrial countries peace.

circuit diagram NPP with nuclear reactor, having water cooling, is shown in fig. 2. Heat generated in core reactor coolant, is taken in by water of the 1st circuit, which is pumped through the reactor by a circulation pump. Heated water from the reactor enters the heat exchanger (steam generator) 3, where it transfers the heat received in the reactor to the water of the 2nd circuit. Water from the 2nd circuit evaporates in the steam generator, and steam is formed, which then enters the turbine 4.

Most often, 4 types of thermal neutron reactors are used at nuclear power plants:

1) water-water with ordinary water as a moderator and coolant;

2) graphite-water with water coolant and graphite moderator;

3) heavy water with a water coolant and heavy water as a moderator;

4) 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 supporting systems include: the reactor itself with biological protection , heat exchangers, pumps or gas-blowing installations that circulate the coolant, pipelines and fittings for the circulation of the circuit, devices for reloading nuclear fuel, systems of special ventilation, emergency cooling, etc.

To protect NPP personnel from radiation exposure, the reactor is surrounded by biological protection, the main material for which are concrete, water, serpentine sand. The reactor circuit equipment must be completely sealed. A system is provided for monitoring the places of possible leakage of the coolant, measures are taken so that the appearance of leaks and breaks in the circuit does not lead to radioactive emissions and pollution of the NPP premises and the surrounding area. Radioactive air and a small amount of coolant vapor, due to the presence of leaks from the circuit, are removed from unattended NPP premises special system ventilation, in which, to exclude the possibility of air pollution, cleaning filters and holding gas holders are provided. The dosimetric control service monitors the compliance with the radiation safety rules by the NPP personnel.

NPPs, which are the most modern look power plants have a number of significant advantages over other types of power plants: under normal operating conditions, they absolutely do not pollute environment, do not require binding to the source of raw materials and, accordingly, can be placed almost anywhere. The new power units have a capacity of almost equal power average HPP, however, the installed capacity utilization factor at nuclear power plants (80%) significantly exceeds that of HPPs or TPPs.

There are practically no significant drawbacks of nuclear power plants under normal operating conditions. However, one cannot fail to notice the danger of nuclear power plants under possible force majeure circumstances: earthquakes, hurricanes, etc. - here old models of power units pose a potential danger of radiation contamination of territories due to uncontrolled overheating of the reactor.

Alternative sources energy.

Energy of sun.

Recently, interest in the problem of using solar energy has increased dramatically, because the potential for energy based on the use of direct solar radiation is extremely high.

The simplest collector of solar radiation is a blackened metal (usually aluminum) sheet, inside of which there are pipes with a liquid circulating in it. Heated by solar energy absorbed by the collector, the liquid is supplied for direct use.

Solar energy is one of the most material-intensive types of energy production. The large-scale use of solar energy entails a gigantic increase in the need for materials, and, consequently, for labor resources for the extraction of raw materials, their enrichment, the production of materials, the manufacture of heliostats, collectors, other equipment, and their transportation.

So far, the electrical energy generated by the sun's rays is much more expensive than that obtained by traditional methods. The scientists hope that the experiments that they will carry out at experimental facilities and stations will help to solve not only technical, but also economic problems.

wind energy.

The energy of moving air masses is enormous. The reserves of wind energy are more than a hundred times greater than the reserves of hydropower of all the rivers of the planet. Winds blow constantly and everywhere on earth. Climatic conditions allow the development of wind energy in a vast area.

But these days, wind-powered engines cover only one-thousandth of the world's energy needs. That is why the design of the wind wheel, the heart of any wind power plant, involves aircraft builders who are able to choose the most appropriate blade profile and study it in a wind tunnel. Through the efforts of scientists and engineers, a wide variety of designs of modern wind turbines have been created.

Earth energy.

Since ancient times, people have known about the elemental manifestations of gigantic energy lurking in the depths the globe. The memory of mankind keeps legends about catastrophic volcanic eruptions that claimed millions human lives, unrecognizably changed the face of many places on Earth. The power of the eruption of even a relatively small volcano is colossal, it many times exceeds the power of the largest power plants created by human hands. True, there is no need to talk about the direct use of the energy of volcanic eruptions, so far people do not have the opportunity to curb this recalcitrant element.

The energy of the Earth is suitable not only for space heating, 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 quite low-power, was built in 1904 in the small Italian town of Larderello. Gradually, the capacity of the power plant grew, more and more new units came 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.

Electricity transmission.

Transformers.

Transformer- a very simple device that allows you to both increase and decrease the voltage. transformation alternating current carried out using transformers. For the first time, transformers were used in 1878 by the Russian scientist P.N. Yablochkov to power the “electric candles” he invented, a new light source at that time. The idea of P. N. Yablochkov was developed by I. F. Usagin, an employee of Moscow University, who designed improved transformers.

The transformer consists of a closed iron core, on which two (sometimes more) coils with wire windings are put on (Fig. 1). One of the windings, called the primary, is connected to an AC voltage source. The second winding, to which the "load" is connected, i.e. devices and devices that consume electricity, is called secondary.

The action of the transformer is based on the phenomenon of electromagnetic induction. When an alternating current passes through the primary winding, an alternating magnetic flux appears in the iron core, which excites the induction EMF in each winding. Moreover, the instantaneous value of the induction emf ein any turn of the primary or secondary winding according to Faraday's law is determined by the formula:

e = -Δ F/Δ t

If F= Ф 0 сosωt, then

e = ω Ф 0sinω t, or

e =E 0 sinω t ,

where E 0 \u003d ω Ф 0 - the amplitude of the EMF in one turn.

In the primary winding, which has p 1 turns, total induction emf e 1 is equal to n 1 e.

There is total EMF in the secondary winding. e 2 is equal to n 2 e, where p 2 is the number of turns of this winding.

Hence it follows that

e 1 e 2 \u003d n 1 n 2. (1)

Sum of voltage u 1 , applied to the primary winding, and the EMF e 1 should be equal to the voltage drop in the primary winding:

u 1 + e 1 = i 1 R 1 , where R 1 is the active resistance of the winding, and i 1 is the current in it. This equation follows directly from the general equation. Usually the active resistance of the winding is small and a member i 1 R 1 can be neglected. That's why

u 1 ≈ - e 1. (2)

When the secondary winding of the transformer is open, the current does not flow in it, and the relation takes place:

u 2 ≈ - e 2 . (3)

Since the instantaneous values of the emf e 1 And e 2 change in phase, then their ratio in formula (1) can be replaced by the ratio of effective values E 1 AndE 2 these EMFs or, taking into account equalities (2) and (3), by the ratio effective values voltage U 1 and U 2 .

U 1 /U 2 = E 1 / E 2 = n 1 / n 2 = k. (4)

Value k called the transformation ratio. If k>1, then the transformer is step-down, with k<1 - increasing.

When the circuit of the secondary winding is closed, current flows in it. Then the relation u 2 ≈ - e 2 is no longer satisfied exactly, and, accordingly, the connection between U 1 and U 2 becomes more complex than in equation (4).

According to the law of conservation of energy, the power in the primary circuit must be equal to the power in the secondary circuit:

U 1 I 1 = U 2 I 2, (5)

where I 1 And I 2 - effective values of the force in the primary and secondary windings.

Hence it follows that

U 1 /U 2 = I 1 / I 2 . (6)

This means that by increasing the voltage several times with the help of a transformer, we reduce the current by the same amount (and vice versa).

Due to the inevitable energy losses for heat generation in the windings and the iron core, equations (5) and (6) are approximately fulfilled. However, in modern high-power transformers, the total losses do not exceed 2-3%.

In everyday practice, you often have to deal with transformers. In addition to those transformers that we use, willy-nilly, due to the fact that industrial devices are designed for one voltage, and another is used in the city network, besides them, we have to deal with car reels. The bobbin is a step-up transformer. To create a spark that ignites the working mixture, a high voltage is required, which we get from the car battery, after first turning the battery’s direct current into alternating current using a breaker. It is easy to see that, up to the loss of energy used to heat the transformer, as the voltage increases, the current decreases, and vice versa.

Welding machines require step-down transformers. Welding requires very high currents, and the transformer of the welding machine has only one output turn.

You probably noticed that the core of the transformer is made from thin sheets of steel. This is done in order not to lose energy during voltage conversion. In sheet material, eddy currents will play a lesser role than in solid material.

At home you are dealing with small transformers. As for powerful transformers, they are huge structures. In these cases, the core with windings is placed in a tank filled with cooling oil.

Electricity transmission

Consumers of electricity are everywhere. It is produced in relatively few places close to sources of fuel and water resources. Therefore, it becomes necessary to transmit electricity over distances sometimes reaching hundreds of kilometers.

But the transmission of electricity over long distances is associated with significant losses. The fact is that, flowing through power lines, the current heats them. In accordance with the Joule-Lenz law, the energy spent on heating the wires of the line is determined by the formula

where R is the line resistance. With a long line, power transmission can become generally uneconomical. To reduce losses, you can, of course, follow the path of reducing the resistance R of the line by increasing the cross-sectional area of \u200b\u200bthe wires. But to reduce R, for example, by a factor of 100, the mass of the wire must also be increased by a factor of 100. It is clear that such a large expenditure of expensive non-ferrous metal cannot be allowed, not to mention the difficulties of fixing heavy wires on high masts, etc. Therefore, energy losses in the line are reduced in another way: by reducing the current in the line. For example, a decrease in current by a factor of 10 reduces the amount of heat released in the conductors by 100 times, i.e., the same effect is achieved as from a hundredfold weighting of the wire.

Since the current power is proportional to the product of the current strength and voltage, in order to maintain the transmitted power, it is necessary to increase the voltage in the transmission line. Moreover, the longer the transmission line, the more profitable it is to use a higher voltage. So, for example, in the high-voltage transmission line Volzhskaya HPP - Moscow, a voltage of 500 kV is used. Meanwhile, alternating current generators are built for voltages not exceeding 16-20 kV, since a higher voltage would require the adoption of more complex special measures to isolate the windings and other parts of the generators.

Therefore, step-up transformers are installed at large power plants. The transformer increases the voltage in the line as much as it reduces the current. The power loss in this case is small.

For the direct use of electricity in the motors of the electric drive of machine tools, in the lighting network and for other purposes, the voltage at the ends of the line must be reduced. This is achieved using step-down transformers. Moreover, usually a decrease in voltage and, accordingly, an increase in current strength occurs in several stages. At each stage, the voltage is getting smaller, and the area covered by the electrical network is getting wider. The scheme of transmission and distribution of electricity is shown in the figure.

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 the uninterrupted supply of energy to consumers, regardless of their location.

The use of electricity.

The use of electric power in various fields of science.

Let's consider these questions on concrete examples. About 80% of GDP growth (gross domestic product) in developed countries is achieved through technical innovation, most 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.

Now they are used in all areas of human activity: for recording and storing information, creating archives, preparing and editing texts, performing drawing and graphic work, automating production and agriculture. Electronization and automation of production are the most important consequences of the "second industrial" or "microelectronic" revolution in the economies of developed countries. The development of integrated automation is directly related to microelectronics, a qualitatively new stage of which began after the invention in 1971 of the microprocessor - a microelectronic logic device built into various devices to control their operation.

Microprocessors have accelerated the growth of robotics. Most of the robots in use today belong to the so-called first generation, and are used in welding, cutting, pressing, coating, etc. The second-generation robots that replace them are equipped with devices for recognizing the environment. And robots - "intellectuals" of the third generation will "see", "feel", "hear". Scientists and engineers call nuclear energy, space exploration, transport, trade, warehousing, medical care, waste processing, and the development of the wealth of the ocean floor among the most priority areas for the use of robots. The majority of robots run on electrical energy, but the increase in robot electricity consumption is offset by the reduction in energy costs in many energy-intensive manufacturing processes through the introduction of smarter methods and new energy-saving technological processes.

But back to science. All new theoretical developments are verified experimentally after computer calculations. And, as a rule, at this stage, research is carried out using physical measurements, chemical analyzes, etc. Here, scientific research tools are diverse - numerous measuring instruments, accelerators, electron microscopes, magnetic resonance tomographs, etc. Most of these instruments of experimental science run on electrical energy.

Science in the field of communications and communications is developing very rapidly. Satellite communication is used not only as a means of international communication, but also in everyday life - satellite dishes are not uncommon in our city. New means of communication, such as fiber technology, can significantly reduce the loss of electricity in the process of transmitting signals over long distances.

Science and the sphere of management did not bypass. As the scientific and technological revolution develops, the production and non-production spheres of human activity expand, management begins to play an increasingly important role in improving their efficiency. From a kind of art, until recently based on experience and intuition, management has now become a science. The science of management, the general laws of receiving, storing, transmitting and processing information is called cybernetics. This term comes from the Greek words "helmsman", "helmsman". It is found in the writings of ancient Greek philosophers. However, its new birth actually took place in 1948, after the publication of the book "Cybernetics" by the American scientist Norbert Wiener.

Before the beginning of the "cybernetic" revolution, there was only paper computer science, the main means of perception of which was the human brain, and which did not use electricity. The "cybernetic" revolution gave rise to a fundamentally different - machine informatics, corresponding to the gigantically increased flows of information, the source of energy for which is electricity. Completely new means of obtaining information, its accumulation, processing and transmission have been created, which together form a complex information structure. It includes automatic control systems (automated control systems), information data banks, automated information bases, computer centers, video terminals, copiers and telegraph machines, nationwide information systems, satellite and high-speed fiber-optic communication systems - all this has unlimitedly expanded the scope of electricity use.

Many scientists believe that in this case we are talking about a new "information" civilization, replacing the traditional organization of an industrial type of society. This specialization is characterized by the following important features:

· widespread use of information technology in material and non-material production, in the field of science, education, healthcare, etc.;

the presence of a wide network of various data banks, including public use;

transformation of information into one of the most important factors of economic, national and personal development;

free circulation of information in society.

Such a transition from an industrial society to an "information civilization" became possible largely due to the development of energy and the provision of a convenient type of energy in transmission and use - electrical energy.

Electricity in production.

Modern society cannot be imagined without the electrification of production activities. Already at the end of the 1980s, 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 proportion may increase to 1/2. Such an increase in electricity consumption is primarily associated with an increase in its consumption in industry. The main part of industrial enterprises works on electric energy. High electricity consumption is typical for energy-intensive industries such as metallurgy, aluminum and engineering industries.

Electricity in the home.

The importance of electricity in our life can be covered with a whole poem, it is so important in our life and we are so used to it. Although we no longer notice that she comes to our homes, but when she is turned off, it becomes very uncomfortable.

Appreciate electricity!

Bibliography.

1. Textbook by S.V. Gromov "Physics, Grade 10". Moscow: Enlightenment.

2. Encyclopedic Dictionary of a Young Physicist. Composition. V.A. Chuyanov, Moscow: Pedagogy.

3. Allion L., Wilcons W.. Physics. Moscow: Nauka.

4. Koltun M. World of Physics. Moscow.

5. Energy sources. Facts, problems, solutions. Moscow: Science and technology.

6. Non-traditional energy sources. Moscow: Knowledge.

7. Yudasin L.S. Energy: problems and hopes. Moscow: Enlightenment.

8. Podgorny A.N. Hydrogen energy. Moscow: Nauka.

Public Educational Institution of the Chuvash Republic SPO "ASHT" of the Ministry of Education of Chuvashia

METHODOLOGICAL

DEVELOPMENT

open class in the discipline "Physics"

Topic: Production, transmission and consumption of electrical energy

highest qualification category

Alatyr, 2012

CONSIDERED

at a meeting of the methodological commission

humanitarian and natural sciences

disciplines

Protocol No. __ dated "___" ______ 2012

Chairman_____________________

Reviewer: Ermakova N.E., Lecturer, BEI CR SPO "ASHT", Chairman of the Central Committee of the Humanities and Natural Sciences

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. It is difficult to imagine the existence of modern civilization without electricity. If the light is turned off in our apartment for at least a few minutes, then we already experience numerous inconveniences. And what happens when there is a power outage for several hours! Electric current is the main source of electricity. That is why it is so important to represent the physical foundations for obtaining, transmitting and using alternating electric current.

Explanatory note
Contents of the main part
Bibliographic list
Applications.

Explanatory note

Goals:
- to acquaint students with the physical foundations of production, transmission and

use of electrical energy

Contribute to the formation of information and communication skills among students

competencies

Deepen knowledge about the development of the electric power industry and related environmental

problems, fostering a sense of responsibility for the preservation of the environment

Rationale for the chosen topic:

It is impossible to imagine our life today without electrical energy. The electric power industry has invaded all spheres of human activity: industry and agriculture, science and space. Our way of life is unthinkable without electricity. Electricity has been and remains the main component of human life. What will be the energy of the XXI century? To answer this question, it is necessary to know the main methods of generating electricity, to study the problems and prospects of modern electricity production not only in Russia, but also in the territory of Chuvashia and Alatyr. This lesson allows students to develop the ability to process information and apply knowledge of theory in practice, develop skills independent work with various sources of information. This lesson reveals the possibilities of forming information and communication competencies

Lesson plan

in the discipline "Physics"
Date: 04/16/2012
Group: 11 tv
Goals:

- educational: - to acquaint students with the physical foundations of production,

transmission and use of electrical energy

Contribute to the formation of information and

communicative competence

Deepen knowledge about the development of the electric power industry and related

these environmental problems, fostering a sense of responsibility

for the preservation of the environment

- developing:: - to form the skills to process information and apply

knowledge of theory in practice;

Develop skills to work independently with a variety of

sources of information

Develop cognitive interest in the subject.
- educational: - to educate the cognitive activity of students;

Develop the ability to listen and be heard;

Cultivate students' independence in acquiring new

knowledge

- develop communication skills when working in groups
A task: formation of key competencies in the study of production, transmission and use of electrical energy
Class type- lesson
Lesson type- combined lesson
Means of education: textbooks, reference books, handouts, multimedia projector,

screen, electronic presentation

Lesson progress:

Organizational moment (checking absentees, group readiness for the lesson)
Target space organization
Checking students' knowledge, reporting the topic and survey plan, setting goals

Topic: "Transformers"

Actions of the teacher

Student actions

Methods

Conducts a frontal conversation, corrects students' answers:

1) What are the advantages of electrical energy over other types of energy?

2) What device is used to change the strength of alternating current and voltage?

3) What is its purpose?

4) What is the structure of the transformer?

6) What is the transformation ratio? How is it numerically?

7) Which transformer is called step-up, which step-down?

8) What is called the power of the transformer?

Offers to solve a problem

Conducts testing
Offers students the keys to the test for self-examination

Answer questions
1. Find the right answers
2. Correct the answers of comrades
3. Develop criteria for their behavior
4. Compare and find common and different in phenomena

Analyze the solution, look for errors, justify the answer

Answer test questions
Conduct cross-checking of tests

Frontal conversation

Problem solving

Testing

Summing up the results of checking the main provisions of the studied section
Reporting a topic, setting a goal, a plan for studying new material

Topic: "Production, transmission and consumption of electricity"
Plan: 1) Power generation:

a) Industrial energy (HPP, TPP, NPP)

b) Alternative energy (GeoTPP, SPP, WPP, TPP)

2) Electricity transmission

3) Efficient use of electrical energy

4) Energy of the Chuvash Republic

Motivation of educational activity of students

Actions of the teacher

Student actions

Study method

Organizes the target space, introduces the plan for studying the topic
Introduces the basic methods of generating electricity
Invites students to highlight the physical foundations of electricity production
Offers to fill in a summary table
Forms the ability to process information, highlight the main thing, analyze, compare, find common and different, draw conclusions;

Recognize goals, write down a plan

Listen, understand, analyze

Make a report, listen to the speaker, comprehend what they heard, draw conclusions

Explore means, summarize, draw conclusions, fill in the table
Compare, find common and different

Advanced independent work

Study
Student reports

Fixing new material

Generalization and systematization of the material.
Summing up the lesson.
Task for independent work of students during extracurricular time.

Textbook § 39-41, complete the table

Topic: Production, transmission and consumption of electricity
It is impossible to imagine our life today without electrical energy. The electric power industry has invaded all spheres of human activity: industry and agriculture, science and space. Our way of life is unthinkable without electricity. Such a widespread use of electricity is due to its advantages over other forms of energy. Electricity has been and remains the main component of human life The main questions - how much energy does humanity need? What will be the energy of the XXI century? To answer these questions, it is necessary to know the main methods of generating electricity, to study the problems and prospects of modern electricity generation not only in Russia, but also in the territory of Chuvashia and Alatyr.

The conversion of various types of energy into electrical energy occurs at power plants. Consider the physical foundations of electricity production at power plants.

Statistical data on electricity production in Russia, billion kWh

Depending on the type of energy being converted, power plants can be divided into the following main types:

Industrial power plants: HPPs, TPPs, NPPs
Alternative energy power plants: PES, SES, WES, GeoTPS

hydroelectric power plants
A hydroelectric power station is a complex of structures and equipment by means of which the energy of the water flow is converted into electrical energy. At a hydroelectric power station, electricity is obtained using the energy of water flowing from a higher level to a lower level and rotating a turbine. The dam is the most important and most expensive element of a hydroelectric power plant. Water flows from the upstream to the downstream through special pipelines or through channels made in the body of the dam and acquires a high speed. The jet of water enters the blades of the hydro turbine. The hydroturbine rotor is driven by the centrifugal force of the water jet. The turbine shaft is connected to the shaft of an electric generator, and when the generator rotor rotates, the mechanical energy of the rotor is converted into electrical energy.
The most important feature of hydropower resources in comparison with fuel and energy resources is their continuous renewal. The lack of need for fuel for HPPs determines the low cost of electricity generated at HPPs. However, hydropower is not environmentally friendly. When a dam is built, a reservoir is formed. Water flooding huge areas irreversibly changes the environment. Raising the river level by a dam can cause waterlogging, salinity, changes in coastal vegetation and microclimate. Therefore, the creation and use of environmentally friendly hydraulic structures is so important.
Thermal power plants
Thermal power plant (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. The main types of fuel for thermal power plants are natural resources - gas, coal, peat, oil shale, fuel oil. Thermal power plants are divided into two groups: condensing and cogeneration or heating plants (CHP). Condensing stations supply consumers only with electrical energy. They are built near deposits of local fuel in order not to carry it over long distances. Heating plants supply consumers not only with electrical energy, but also with heat - steam or hot water, so CHPs are built near heat receivers, in the centers of industrial regions and large cities to reduce the length of heating networks. The fuel is transported to the CHPP from the places of its production. A boiler with water is installed in the engine room of the TPP. Due to the heat generated as a result of fuel combustion, the water in the steam boiler heats up, evaporates, and the resulting saturated steam is brought to a temperature of 550 ° C and, under a pressure of 25 MPa, enters the steam turbine through the steam pipeline, the purpose of which is to convert the thermal energy of steam into mechanical energy. The motion energy of the steam turbine is converted into electrical energy by a generator, the shaft of which is directly connected to the turbine shaft. After the steam turbine, water vapor, already having a low pressure and a temperature of about 25 ° C, enters the condenser. Here, the steam is converted into water by means of cooling water, which is fed back to the boiler by means of a pump. The cycle starts again. Thermal power plants operate on fossil fuels, but these are, unfortunately, irreplaceable natural resources. In addition, the operation of thermal power plants is accompanied by environmental problems: when fuel is burned, thermal and chemical pollution of the environment occurs, which has a detrimental effect on the living world of water bodies and the quality of drinking water.
Nuclear power plants
Nuclear power plant (NPP) is a power plant in which nuclear (nuclear) energy is converted into electrical energy. Nuclear power plants operate on the same principle as thermal power plants, but they use the energy obtained from the fission of heavy atomic nuclei (uranium, plutonium) for vaporization. Nuclear reactions take place in the reactor core, accompanied by the release of enormous energy. The water that comes into contact with the fuel elements in the reactor core takes heat from them and transfers this heat in the heat exchanger also to water, but no longer posing a danger of radioactive radiation. Since the water in the heat exchanger turns into steam, it is called a steam generator. Hot steam enters the turbine, which converts the thermal energy of the steam into mechanical energy. The motion energy of the steam turbine is converted into electrical energy by a generator, the shaft of which is directly connected to the turbine shaft. Nuclear power plants, which are the most modern type of power plants, have a number of significant advantages over other types of power plants: they do not require binding to a source of raw materials and can actually be placed anywhere, and are considered environmentally safe during normal operation. But in case of accidents at nuclear power plants, there is a potential danger of radiation pollution of the environment. In addition, the disposal of radioactive waste and the dismantling of nuclear power plants that have served their time remain a significant problem.
Alternative energy is a set of promising methods of obtaining energy that are not as widespread as traditional ones, but are of interest because of the profitability of their use with a low risk of harm to the ecology of the area. Alternative energy source - a method, device or structure that allows you to receive electrical energy (or other required type of energy) and replaces traditional energy sources that operate on oil, natural gas and coal. The purpose of the search for alternative energy sources is the need to obtain it from the energy of renewable or practically inexhaustible natural resources and phenomena.
Tidal power plants
The use of tidal energy began in the 11th century, when mills and sawmills appeared on the shores of the White and North Seas. Twice a day, the ocean level then rises under the influence of the gravitational forces of the Moon and the Sun, which attract masses of water to themselves. Away from the coast, fluctuations in the water level do not exceed 1 m, but near the coast they can reach 13-18 meters. For the device of the simplest tidal power plant (PES), a pool is needed - a bay blocked by a dam or a river mouth. There are culverts in the dam and hydraulic turbines are installed that rotate the generator. It is considered economically feasible to build tidal power plants in areas with tidal sea level fluctuations of at least 4 meters. In double-acting tidal power plants, the turbines are driven by the movement of water from the sea to the pool and back. Two-way tidal power plants are capable of generating electricity continuously for 4-5 hours with breaks of 1-2 hours four times a day. To increase the operation time of turbines, there are more complex schemes - with two, three and more pools, but the cost of such projects is very high. The disadvantage of tidal power plants is that they are built only on the shores of the seas and oceans, besides, they do not develop very high power, and the tides occur only twice a day. And even they are not environmentally friendly. They disrupt the normal exchange of salt and fresh water and thus the living conditions of marine flora and fauna. They also affect the climate, since they change the energy potential of sea waters, their speed and the territory of movement.
wind farms
Wind energy is an indirect form of solar energy, resulting from the difference in temperature and pressure in the Earth's atmosphere. About 2% of the solar energy that reaches Earth is converted into wind energy. Wind is a renewable energy source. Its energy can be used in almost all areas of the Earth. Getting electricity from wind power plants is an extremely attractive, but at the same time technically challenging task. The difficulty lies in the very large dispersion of wind energy and in its inconstancy. The principle of operation of wind farms is simple: the wind turns the blades of the installation, setting the shaft of the generator in motion. The generator generates electrical energy, and thus wind energy is converted into electrical current. Wind farms are very cheap to produce, but their capacity is small and they depend on the weather to operate. In addition, they are very noisy, so large installations even have to be turned off at night. In addition, wind farms interfere with air traffic, and even radio waves. The use of wind farms causes a local weakening of the strength of air flows, which interferes with the ventilation of industrial areas and even affects the climate. Finally, for the use of wind farms, huge areas are needed, much more than for other types of power generators. Nevertheless, isolated wind farms with heat engines as a reserve and wind farms that operate in parallel with heat and hydro plants should take a prominent place in the energy supply of those areas where wind speed exceeds 5 m/s.
geothermal power plants
Geothermal energy is the energy of the interior of the Earth. The eruption of volcanoes is a clear evidence of the enormous heat inside the planet. Scientists estimate the temperature of the Earth's core at thousands of degrees Celsius. Geothermal heat is the heat contained in underground hot water and water vapor, and the heat of heated dry rocks. Geothermal thermal power plants (GeoTPPs) convert the internal heat of the Earth (the energy of hot steam-water sources) into electrical energy. Sources of geothermal energy can be underground pools of natural heat carriers - hot water or steam. In essence, these are directly ready-to-use "underground boilers" from where water or steam can be extracted using ordinary boreholes. The natural steam obtained in this way, after preliminary purification from gases that cause the destruction of pipes, is sent to turbines connected to electric generators. The use of geothermal energy does not require high costs, because. in this case, we are talking about already “ready-to-use”, energy sources created by nature itself. The disadvantages of GeoTPP include the possibility of local subsidence of soils and the awakening of seismic activity. And the gases coming out of the ground create a lot of noise in the vicinity and can, moreover, contain toxic substances. In addition, it is not possible to build a GeoTPP everywhere, because geological conditions are necessary for its construction.
Solar power plants
Solar energy is the most grandiose, cheap, but, perhaps, the least used source of energy by man. The conversion of solar energy into electrical energy is carried out with the help of solar power plants. There are thermodynamic solar power plants, in which solar energy is first converted into heat, and then into electricity; and photovoltaic plants that directly convert solar energy into electrical energy. Photovoltaic stations provide uninterrupted power to river buoys, signal lights, emergency communication systems, beacon lamps and many other objects located in hard-to-reach places. As solar batteries improve, they will be used in residential buildings for autonomous power supply (heating, hot water supply, lighting and powering household appliances). Solar power plants have a significant advantage over other types of plants: the absence of harmful emissions and environmental cleanliness, noiseless operation, and the preservation of the earth's interior intact.
Transmission of electricity over a distance
Electricity is produced near sources of fuel or water resources, while its consumers are located everywhere. Therefore, there is a need to transmit electricity over long distances. Consider a schematic diagram of the transmission of electricity from a generator to a consumer. Typically, alternating current generators in power plants produce a voltage not exceeding 20 kV, since at higher voltages the possibility of electrical breakdown of the insulation in the winding and in other parts of the generator sharply increases. To maintain the transmitted power, the voltage in the power transmission line should be maximum, so step-up transformers are installed at large power plants. However, the voltage in the power line is limited: if the voltage is too high, discharges occur between the wires, leading to energy losses. For the use of electricity in industrial enterprises, a significant reduction in voltage is required, carried out with the help of step-down transformers. A further reduction in voltage to a value of about 4 kV is necessary for power distribution through local networks, i.e. along the wires that we see on the outskirts of our cities. Less powerful transformers reduce the voltage to 220 V (the voltage used by most individual consumers).

Efficient use of electricity
Electricity occupies a significant place in the expense item of every family. Its effective use will significantly reduce costs. Increasingly, computers, dishwashers, food processors are “registered” in our apartments. Therefore, the cost of electricity is very significant. Increased energy consumption leads to additional consumption of non-renewable natural resources: coal, oil, gas. When fuel is burned, carbon dioxide is released into the atmosphere, which leads to harmful climate change. Saving electricity allows you to reduce the consumption of natural resources, and therefore reduce emissions of harmful substances into the atmosphere.

Four steps of energy saving

Don't forget to turn off the lights.
Use energy-saving light bulbs and class A household appliances.
It is good to insulate windows and doors.
Install heat supply regulators (coils with a valve).

The energy industry of Chuvashia is one of the most developed industries of the republic, on the work of which social, economic and political well-being directly depends. Energy is the basis for the functioning of the economy and the life support of the republic. The work of the energy complex of Chuvashia is so firmly connected with the daily life of every enterprise, institution, firm, house, every apartment and, as a result, every inhabitant of our republic.

At the very beginning of the 20th century, when the electric power industry was still taking its first practical steps.

Before 1917 On the territory of modern Chuvashia there was not a single electric power station for public use. Peasant houses were lit with a torch.

There were only 16 prime movers in industry. In the Alatyrsky district, electricity was produced and used at a sawmill and flour mills. There was a small power plant at the distillery near Marposad. Merchants Talantsevs had their own power plant at the oil mill in Yadrin. In Cheboksary, the merchant Efremov had a small power plant. She served the sawmill and its two houses.

There was almost no light both in the houses and on the streets of the cities of Chuvashia.

The development of energy in Chuvashia begins after 1917. Since 1918 the construction of public power plants begins, a lot of work is underway to create an electric power industry in the city of Alatyr. It was decided to build the first power plant at that time at the former Popov plant.

In Cheboksary, the department of communal services dealt with electrification issues. Through his efforts in 1918. the power plant at the sawmill, owned by the merchant Efremov, resumed operation. Electricity was delivered through two lines to government institutions and street lighting.

The formation of the Chuvash Autonomous Region (June 24, 1920) created favorable conditions for the development of energy. It was in 1920. in connection with the acute need, the regional department of public utilities equipped the first small power plant in Cheboksary, with a capacity of 12 kW.

Mariinsko-Posad power plant was equipped in 1919. The Marposad city power station began to provide electricity. The Tsivilskaya power plant was built in 1919, but due to the lack of power lines, electricity supply began to be produced only from 1923.

Thus, the first foundations of Chuvashia's power industry were laid during the years of intervention and civil war. The first small municipal power plants for public use with a total capacity of about 20 kW were created.

Before the revolution of 1917, there was not a single electric station for public use on the territory of Chuvashia; a torch reigned in the houses. With a torch or a kerosene lamp, they worked even in small workshops. Here, handicraftsmen used mechanically driven equipment. At more solid enterprises, where agricultural and forest products were processed, paper was boiled, butter was churned and flour was ground,

there were 16 low-power engines.

Under the Bolsheviks, the city of Alatyr became a pioneer in the energy sector of Chuvashia. In this small town, thanks to the efforts of the local economic council, the first public power station appeared.

In Cheboksary, all electrification in 1918 was reduced to the fact that the power plant was restored at a sawmill confiscated from the merchant Efremov, which became known as the "Name of October 25". However, its electricity was only enough to light some streets and state institutions (according to statistics, in 1920, about 100 light bulbs with a capacity of 20 candles shone for city officials).

In 1924, three more small power plants were built, and, on October 1, 1924, the Chuvash Association of Communal Power Plants, CHOKES, was created to manage the expanding energy base. In 1925, the State Planning Committee of the republic adopted an electrification plan, which provided for the construction of 8 new power plants in 5 years - 5 urban (in Cheboksary, Kanash, Marposad, Tsivilsk and Yadrin) and 3 rural (in Ibresy, Vurnary and Urmary). The implementation of this project made it possible to electrify 100 villages - mainly in the Cheboksary and Tsivilsky districts and along the Cheboksary-Kanash highway, 700 peasant households, and some handicraft workshops.
During 1929-1932, the capacity of municipal and industrial power plants of the republic increased almost 10 times; electricity generation by these power plants has increased almost 30 times.

During the Great Patriotic War, great measures were taken to strengthen and develop the energy base of the republic's industry. The increase in capacities occurred mainly due to the growth in the capacities of district, communal and rural power plants. The power engineers of Chuvashia withstood the ordeal with honor and fulfilled their patriotic duty. They understood that the electricity produced was necessary, first of all, for enterprises fulfilling orders from the front.

During the years of the post-war five-year plan in the Chuvash ASSR, 102 rural power plants were built and put into operation, incl. 69 HPPs and 33 TPPs. The supply of electricity to agriculture has tripled in comparison with 1945.
In 1953, in Alatyr, by order signed by Stalin, the construction of the Alatyr TPP began. The first turbogenerator with a capacity of 4 MW was put into operation in 1957, the 2nd - in 1959. According to forecasts, the power of the TPP should have been enough until 1985 for both the city and the region and to provide electricity to the Turgenev Svetozavod in Mordovia.

Bibliographic list

Textbook by S.V. Gromov "Physics, Grade 10". Moscow: Enlightenment.
Encyclopedic Dictionary of a Young Physicist. Composition. V.A. Chuyanov, Moscow: Pedagogy.
Allion L., Wilcons W.. Physics. Moscow: Nauka.
Koltun M. World of Physics. Moscow.
Energy sources. Facts, problems, solutions. Moscow: Science and technology.
Non-traditional energy sources. Moscow: Knowledge.
Yudasin L.S. Energy: problems and hopes. Moscow: Enlightenment.
Podgorny A.N. Hydrogen energy. Moscow: Nauka.

Appendix

Power station	Primary Energy Source	Conversion scheme energy	Advantages	disadvantages






GeoTPP				.

Self-control sheet

Finish the sentence: The power system is Power plant electrical system Electrical system of a single city The electrical system of the regions of the country, connected by high-voltage power lines	Energy system - The electrical system of the regions of the country, connected by high-voltage power lines
What is the source of energy in a hydroelectric power station? Oil, coal, gas Wind energy water energy
What energy sources - renewable or non-renewable - are used in the Republic of Chuvashia?	non-renewable
Arrange in chronological order the sources of energy that became available to mankind, starting with the earliest: A. Electric traction; B. Atomic energy; B. Muscular energy of domestic animals; D. Steam energy.
Name the sources of energy known to you, the use of which will reduce the environmental impact of the electric power industry.	PES GeoTPP
Check yourself with the answers on the screen and rate: 5 correct answers - 5 4 correct answers - 4 3 correct answers - 3

I Introduction
II Production and use of electricity
1. Power generation
1.1 Generator
2. Electricity use
III Transformers
1. Appointment
2. Classification
3. Device
4. Characteristics
5. Modes
5.1 Idling
5.2 Short circuit mode
5.3 Load mode
IV Power transmission
V GOELRO
1. History
2. Results
VI List of references

I Introduction

Electricity, one of the most important types of energy, plays a huge role in the modern world. It is the core of the economies of states, determining their position in the international arena and the level of development. Huge sums of money are invested annually in the development of scientific industries related to electricity.
Electricity is an integral part of everyday life, so it is important to have information about the features of its production and use.

II. Production and use of electricity

1. Power generation

Electricity generation is the production of electricity by converting it from other types of energy using special technical devices.
To generate electricity use:
Electric generator - an electrical machine in which mechanical work is converted into electrical energy.
A solar battery or photocell is an electronic device that converts the energy of electromagnetic radiation, mainly in the light range, into electrical energy.
Chemical current sources - the conversion of part of chemical energy into electrical energy, through a chemical reaction.
Radioisotope sources of electricity are devices that use the energy released during radioactive decay to heat the coolant or convert it into electricity.
Electricity is generated at power plants: thermal, hydraulic, nuclear, solar, geothermal, wind and others.
Practically at all power plants of industrial importance, the following scheme is used: the energy of the primary energy carrier with the help of a special device is first converted into mechanical energy of rotational motion, which is transferred to a special electrical machine - a generator, where electric current is generated.
The main three types of power plants: thermal power plants, hydroelectric power plants, nuclear power plants
The leading role in the electric power industry of many countries is played by thermal power plants (TPPs).
Thermal power plants require a huge amount of organic fuel, while its reserves are declining, and the cost is constantly increasing due to increasingly difficult production conditions and transportation distances. The fuel utilization factor in them is quite low (no more than 40%), and the volumes of waste polluting the environment are large.
Economic, technical, economic and environmental factors do not allow us to consider thermal power plants as a promising way to generate electricity.
Hydropower plants (HPP) are the most economical. Their efficiency reaches 93%, and the cost of one kWh is 5 times cheaper than with other methods of generating electricity. They use an inexhaustible source of energy, are serviced by a minimum number of workers, and are well regulated. Our country occupies a leading position in the world in terms of the size and capacity of individual hydroelectric stations and units.
But the pace of development is hindered by significant costs and construction time, due to the remoteness of HPP construction sites from large cities, the lack of roads, difficult construction conditions, are affected by the seasonality of the river regime, large areas of valuable riverine lands are flooded by reservoirs, large reservoirs negatively affect the environmental situation, powerful HPPs can only be built where the appropriate resources are available.
Nuclear power plants (NPPs) operate on the same principle as thermal power plants, i.e., the thermal energy of steam is converted into mechanical energy of rotation of the turbine shaft, which drives a generator, where mechanical energy is converted into electrical energy.
The main advantage of nuclear power plants is the small amount of fuel used (1 kg of enriched uranium replaces 2.5 thousand tons of coal), as a result of which nuclear power plants can be built in any energy-deficient areas. In addition, the reserves of uranium on Earth exceed the reserves of traditional mineral fuel, and with trouble-free operation of nuclear power plants, they have little impact on the environment.
The main disadvantage of nuclear power plants is the possibility of accidents with catastrophic consequences, the prevention of which requires serious safety measures. In addition, nuclear power plants are poorly regulated (it takes several weeks to completely stop or turn them on), and technologies for processing radioactive waste have not been developed.
Nuclear power has grown into one of the leading sectors of the national economy and continues to develop rapidly, ensuring safety and environmental friendliness.

1.1 Generator

An electric generator is a device in which non-electrical forms of energy (mechanical, chemical, thermal) are converted into electrical energy.
The principle of operation of the generator is based on the phenomenon electromagnetic induction when an EMF is induced in a conductor moving in a magnetic field and crossing its magnetic field lines. Therefore, such a conductor can be considered by us as a source of electrical energy.
The method of obtaining an induced emf, in which the conductor moves in a magnetic field, moving up or down, is very inconvenient in its practical use. Therefore, generators use not rectilinear, but rotational movement of the conductor.
The main parts of any generator are: a system of magnets or, most often, electromagnets that create a magnetic field, and a system of conductors that cross this magnetic field.
An alternator is an electrical machine that converts mechanical energy into AC electrical energy. Most alternators use a rotating magnetic field.

When the frame rotates, the magnetic flux through it changes, so an EMF is induced in it. Since the frame is connected to an external electrical circuit with the help of a current collector (rings and brushes), an electric current arises in the frame and the external circuit.
With uniform rotation of the frame, the angle of rotation changes according to the law:

The magnetic flux through the frame also changes over time, its dependence is determined by the function:

where S− frame area.
According to Faraday's law of electromagnetic induction, the EMF of induction that occurs in the frame is:

where is the amplitude of the EMF of induction.
Another value that characterizes the generator is the current strength, expressed by the formula:

where i is the current strength at any given time, I m- the amplitude of the current strength (the maximum value of the current strength in absolute value), φ c- phase shift between fluctuations in current and voltage.
The electrical voltage at the generator terminals varies according to a sinusoidal or cosine law:

Almost all generators installed in our power plants are three-phase current generators. In essence, each such generator is a connection in one electric machine of three alternating current generators, designed in such a way that the EMF induced in them are shifted relative to each other by one third of the period:

2. Electricity use

Power supply of industrial enterprises. Industrial enterprises consume 30-70% of the electricity generated as part of the electric power system. A significant spread of industrial consumption is determined by the industrial development and climatic conditions of various countries.
Power supply of electrified transport. DC electric transport rectifier substations (urban, industrial, intercity) and step-down substations of long-distance electric transport on alternating current are powered by electricity from the electrical networks of the EPS.
Power supply of household consumers. This group of PE includes a wide range of buildings located in residential areas of cities and towns. These are residential buildings, buildings for administrative and managerial purposes, educational and scientific institutions, shops, buildings for healthcare, cultural and mass purposes, public catering, etc.

III. transformers

Transformer - a static electromagnetic device having two or more inductively coupled windings and designed to convert one (primary) alternating current system into another (secondary) alternating current system by means of electromagnetic induction.

Transformer device diagram

1 - primary winding of the transformer
2 - magnetic core
3 - secondary winding of the transformer
F- direction of magnetic flux
U 1- voltage on the primary winding
U 2- voltage on the secondary winding

The first transformers with an open magnetic circuit were proposed in 1876 by P.N. Yablochkov, who used them to power an electric "candle". In 1885, the Hungarian scientists M. Deri, O. Blaty, K. Zipernovsky developed single-phase industrial transformers with a closed magnetic circuit. In 1889-1891. M.O. Dolivo-Dobrovolsky proposed a three-phase transformer.

1. Appointment

Transformers are widely used in various fields:
For transmission and distribution of electrical energy
Typically, at power plants, alternating current generators generate electrical energy at a voltage of 6-24 kV, and it is profitable to transmit electricity over long distances at much higher voltages (110, 220, 330, 400, 500, and 750 kV). Therefore, at each power plant, transformers are installed that increase the voltage.
The distribution of electrical energy between industrial enterprises, settlements, in cities and rural areas, as well as within industrial enterprises, is carried out via overhead and cable lines, at a voltage of 220, 110, 35, 20, 10 and 6 kV. Therefore, transformers must be installed in all distribution nodes that reduce the voltage to 220, 380 and 660 V.
To provide the desired circuit for switching on valves in converter devices and to match the voltage at the output and input of the converter (converter transformers).
For various technological purposes: welding (welding transformers), power supply of electrothermal installations (electric furnace transformers), etc.
For powering various circuits of radio equipment, electronic equipment, communication and automation devices, household appliances, for separating electrical circuits of various elements of these devices, for matching voltage, etc.
To include electrical measuring instruments and some devices (relays, etc.) in high voltage electrical circuits or in circuits through which large currents pass, in order to expand the measurement limits and ensure electrical safety. (measuring transformers)

2. Classification

Transformer classification:

By appointment: general power (used in power transmission and distribution lines) and special applications (furnace, rectifier, welding, radio transformers).
By type of cooling: with air (dry transformers) and oil (oil transformers) cooling.
According to the number of phases on the primary side: single-phase and three-phase.
According to the shape of the magnetic circuit: rod, armored, toroidal.
By the number of windings per phase: two-winding, three-winding, multi-winding (more than three windings).
By winding design: with concentric and alternating (disk) windings.

3. Device

The simplest transformer (single-phase transformer) is a device consisting of a steel core and two windings.

The principle of the device of a single-phase two-winding transformer
The magnetic core is the magnetic system of the transformer, through which the main magnetic flux closes.
When an alternating voltage is applied to the primary winding, an EMF of the same frequency is induced in the secondary winding. If an electrical receiver is connected to the secondary winding, then an electric current arises in it and a voltage is set at the secondary terminals of the transformer, which is somewhat less than the EMF and to some relatively small extent depends on the load.

Symbol of the transformer:
a) - a transformer with a steel core, b) - a transformer with a ferrite core

4. Characteristics of the transformer

The rated power of a transformer is the power for which it is designed.
Rated primary voltage - the voltage for which the primary winding of the transformer is designed.
Rated secondary voltage - the voltage at the terminals of the secondary winding, obtained when the transformer is idling and the rated voltage at the terminals of the primary winding.
Rated currents are determined by the respective power and voltage ratings.
The highest rated voltage of the transformer is the highest of the rated voltages of the transformer windings.
The lowest rated voltage is the smallest of the rated voltages of the transformer windings.
Average rated voltage - rated voltage, which is intermediate between the highest and lowest rated voltage of the transformer windings.

5. Modes

5.1 Idling

Idle mode - the mode of operation of the transformer, in which the secondary winding of the transformer is open, and alternating voltage is applied to the terminals of the primary winding.

A current flows in the primary winding of a transformer connected to an alternating current source, as a result of which an alternating magnetic flux appears in the core Φ penetrating both windings. Since Φ is the same in both windings of the transformer, the change Φ leads to the appearance of the same induction EMF in each turn of the primary and secondary windings. Instantaneous value of induction emf e in any turn of the windings is the same and is determined by the formula:

where is the amplitude of the EMF in one turn.
The amplitude of the induction EMF in the primary and secondary windings will be proportional to the number of turns in the corresponding winding:

where N 1 And N 2- the number of turns in them.
The voltage drop across the primary winding, like across a resistor, is very small compared to ε 1, and therefore for the effective values of the voltage in the primary U 1 and secondary U 2 windings, the following expression will be true:

K- transformation ratio. At K>1 step-down transformer, and when K<1 - повышающий.

5.2 Short circuit mode

Short circuit mode - a mode when the outputs of the secondary winding are closed by a current conductor with a resistance equal to zero ( Z=0).

A short circuit of the transformer under operating conditions creates an emergency mode, since the secondary current, and therefore the primary one, increases several tens of times compared to the nominal one. Therefore, in circuits with transformers, protection is provided that, in the event of a short circuit, automatically turns off the transformer.

Two modes of short circuit must be distinguished:

Emergency mode - when the secondary winding is closed at the rated primary voltage. With such a circuit, the currents increase by a factor of 15–20. The winding is deformed, and the insulation is charred. Iron also burns. This is hard mode. Maximum and gas protection disconnects the transformer from the network in case of an emergency short circuit.

An experimental short circuit mode is a mode when the secondary winding is short-circuited, and such a reduced voltage is supplied to the primary winding, when the rated current flows through the windings - this is U K- short circuit voltage.

Under laboratory conditions, a test short circuit of the transformer can be carried out. In this case, expressed as a percentage, the voltage U K, at I 1 \u003d I 1nom designate u K and is called the short circuit voltage of the transformer:

where U 1nom- rated primary voltage.

This is the characteristic of the transformer, indicated in the passport.

5.3 Load mode

The load mode of the transformer is the mode of operation of the transformer in the presence of currents in at least two of its main windings, each of which is closed to an external circuit, while currents flowing in two or more windings in idle mode are not taken into account:

If a voltage is connected to the primary winding of the transformer U 1, and connect the secondary winding to the load, currents will appear in the windings I 1 And I 2. These currents will create magnetic fluxes Φ 1 And Φ2 directed towards each other. The total magnetic flux in the magnetic circuit decreases. As a result, the EMF induced by the total flow ε 1 And ε 2 decrease. RMS voltage U 1 remains unchanged. Decrease ε 1 causes an increase in current I 1:

With increasing current I 1 flow Φ 1 increases just enough to compensate for the demagnetizing effect of the flux Φ2. Equilibrium is restored again at practically the same value of the total flow.

IV. Electricity transmission

The transmission of electricity from the power plant to consumers is one of the most important tasks of the energy industry.
Electricity is transmitted predominantly via AC overhead transmission lines (TL), although there is a trend towards an increasing use of cable lines and DC lines.

The need to transmit electricity over a distance is due to the fact that electricity is generated by large power plants with powerful units, and is consumed by relatively low-power power consumers distributed over a large area. The trend towards the concentration of generating capacities is explained by the fact that with their growth, the relative costs for the construction of power plants decrease and the cost of generated electricity decreases.
The placement of powerful power plants is carried out taking into account a number of factors, such as the availability of energy resources, their type, reserves and transportation possibilities, natural conditions, the ability to work as part of a single energy system, etc. Often, such power plants turn out to be significantly remote from the main centers of electricity consumption. The operation of unified electric power systems covering vast territories depends on the efficiency of electric power transmission over a distance.
It is necessary to transfer electricity from the places of its production to consumers with minimal losses. The main reason for these losses is the conversion of part of the electricity into the internal energy of the wires, their heating.

According to the Joule-Lenz law, the amount of heat Q, released during the time t in the conductor by resistance R during the passage of current I, equals:

It follows from the formula that in order to reduce the heating of the wires, it is necessary to reduce the current strength in them and their resistance. To reduce the resistance of the wires, increase their diameter, however, very thick wires hanging between power line supports can break under the action of gravity, especially during snowfall. In addition, with an increase in the thickness of the wires, their cost increases, and they are made of a relatively expensive metal - copper. Therefore, a more effective way to minimize energy losses in the transmission of electricity is to reduce the current strength in the wires.
Thus, in order to reduce the heating of wires when transmitting electricity over long distances, it is necessary to make the current in them as small as possible.
The current power is equal to the product of the current strength and voltage:

Therefore, in order to save power transmitted over long distances, it is necessary to increase the voltage by the same amount as the current strength in the wires was reduced:

From the formula it follows that at constant values of the transmitted power of the current and the resistance of the wires, the heating losses in the wires are inversely proportional to the square of the voltage in the network. Therefore, to transmit electricity over distances of several hundred kilometers, high-voltage power lines (TL) are used, the voltage between the wires of which is tens, and sometimes hundreds of thousands of volts.
With the help of power lines, neighboring power plants are combined into a single network, called the power system. The Unified Energy System of Russia includes a huge number of power plants controlled from a single center and provides uninterrupted power supply to consumers.

V. GOELRO

1. History

GOELRO (State Commission for the Electrification of Russia) is a body created on February 21, 1920 to develop a project for the electrification of Russia after the October Revolution of 1917.

More than 200 scientists and technicians were involved in the work of the commission. G.M. headed the commission. Krzhizhanovsky. The Central Committee of the Communist Party and personally V. I. Lenin daily directed the work of the GOELRO commission, determined the main fundamental provisions of the country's electrification plan.

By the end of 1920, the commission had done an enormous amount of work and prepared the Plan for the Electrification of the RSFSR, a volume of 650 pages of text with maps and schemes for the electrification of regions.
The GOELRO plan, designed for 10-15 years, implemented Lenin's ideas of electrifying the entire country and creating a large industry.
In the field of electric power economy, the plan consisted of a program designed for the restoration and reconstruction of the pre-war electric power industry, the construction of 30 regional power stations, and the construction of powerful regional thermal power plants. It was planned to equip the power plants with large boilers and turbines for that time.
One of the main ideas of the plan was the widespread use of the country's vast hydropower resources. Provision was made for a radical reconstruction on the basis of the electrification of all branches of the national economy of the country, and primarily for the growth of heavy industry, and the rational distribution of industry throughout the country.
The implementation of the GOELRO plan began in the difficult conditions of the Civil War and economic devastation.

Since 1947, the USSR has been ranked first in Europe and second in the world in terms of electricity generation.

The GOELRO plan played a huge role in the life of our country: without it, it would not have been possible to bring the USSR into the ranks of the most industrially developed countries in the world in such a short time. The implementation of this plan shaped the entire domestic economy and still largely determines it.

The drafting and implementation of the GOELRO plan became possible and solely due to a combination of many objective and subjective factors: the considerable industrial and economic potential of pre-revolutionary Russia, the high level of the Russian scientific and technical school, the concentration of all economic and political power, its strength and will, and also the traditional conciliar-communal mentality of the people and their obedient and trusting attitude towards the supreme rulers.
The GOELRO plan and its implementation proved the high efficiency of the state planning system under conditions of rigidly centralized power and predetermined the development of this system for many decades to come.

2. Results

By the end of 1935, the electrical construction program had been overfulfilled by several times.

Instead of 30, 40 regional power plants were built, at which, together with other large industrial stations, 6,914 thousand kW of capacity were commissioned (of which 4,540 thousand kW were regional, almost three times more than according to the GOELRO plan).
In 1935, there were 13 power plants of 100,000 kW among the regional power plants.

Before the revolution, the capacity of the largest power plant in Russia (1st Moscow) was only 75 thousand kW; there was not a single large hydroelectric power station. By the beginning of 1935, the total installed capacity of hydroelectric power stations had reached almost 700,000 kW.
The world's largest at that time, the Dnieper hydroelectric power station, Svirskaya 3rd, Volkhovskaya, and others were built. At the highest point of its development, the Unified Energy System of the USSR in many respects surpassed the energy systems of the developed countries of Europe and America.

Electricity was practically unknown in the villages before the revolution. Large landowners installed small power plants, but their numbers were few.

Electricity began to be used in agriculture: in mills, fodder cutters, grain cleaning machines, and sawmills; in industry, and later - in everyday life.

List of used literature

Venikov V. A., Long-distance power transmission, M.-L., 1960;
Sovalov S. A., Power transmission modes 400-500 kv. EES, M., 1967;
Bessonov, L.A. Theoretical foundations of electrical engineering. Electric circuits: textbook / L.A. Bessonov. - 10th ed. — M.: Gardariki, 2002.
Electrical engineering: Educational and methodical complex. /AND. M. Kogol, G. P. Dubovitsky, V. N. Borodianko, V. S. Gun, N. V. Klinachev, V. V. Krymsky, A. Ya. Ergard, V. A. Yakovlev; Edited by N.V. Klinacheva. - Chelyabinsk, 2006-2008.
Electrical systems, v. 3 - Power transmission by alternating and direct current of high voltage, M., 1972.

Sorry, nothing was found.

Home > Abstract

abstract

in physics

on the topic "Production, transmission and use of electricity"

11th grade A students

MOU school number 85

Catherine.

Teacher:

2003

Abstract plan.

Introduction. 1. Power generation.

types of power plants. alternative energy sources.2. Electricity transmission.

transformers.3. The use of electricity.

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 remedy, an assistant in agriculture, a food preservative, a technological tool, etc. The wonderful myth of Prometheus, who gave people fire, appeared in ancient Greece much later than in many parts of the world, methods of quite sophisticated handling of fire, its production and extinguishing, conservation of fire and rational use fuel. For many years, the 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 the 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 fossil fuels. The first thermal power plants appeared at the end of the 19th century and became widespread. In the mid-70s of the 20th century, TPPs were the main type of electrical stations. At thermal power plants, the chemical energy of the fuel is converted first into mechanical and then into electrical energy. The fuel for such a power plant can be coal, peat, gas, oil shale, fuel oil. Thermal power plants are divided into condensation(IES), designed to generate only electrical energy, and combined heat and power plants(CHP), producing in addition to electrical heat energy in the form of hot water and steam. Large IESs of district significance are called state district power plants (GRES). 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 plant 2, where it turns into dust. Coal dust enters the furnace of the steam generator (steam boiler) 3, which has a system of pipes in which chemically purified water, called feed water, circulates. In the boiler, the water heats up, evaporates, and the resulting saturated steam is brought to a temperature of 400-650 ° C and, under a pressure of 3-24 MPa, enters the steam turbine 4 through the steam pipeline. The steam parameters depend on the power of the units. Thermal condensing power plants have a low efficiency (30-40%), since most of the energy is lost with flue gases and condenser cooling water. It is advantageous to build IES in the immediate vicinity of fuel extraction sites. At the same time, consumers of electricity can be located at a considerable distance from the station. combined heat and power plant differs from the condensing station with a special heating turbine installed on it with steam extraction. At the CHPP, one part of the steam is completely used in the turbine to generate electricity in the generator 5 and then enters the condenser 6, while the other part, which has a high temperature and pressure, is taken from the intermediate stage of the turbine and used for heat supply. The condensate is supplied by pump 7 through deaerator 8 and further by feed pump 9 to the steam generator. The amount of extracted steam depends on the needs of enterprises for thermal energy. The efficiency of CHP reaches 60-70%. Such stations are usually built near consumers - industrial enterprises or residential areas. Most often they work on imported fuel. Much less widespread are thermal stations with gas turbine(GTPS), steam-gas(PGES) and diesel plants. Gas or liquid fuel is burned in the GTPP combustion chamber; combustion products with a temperature of 750-900 ºС enter the gas turbine that rotates the electric generator. The efficiency of such thermal power plants is usually 26-28%, the power is up to several hundreds of MW . GTPPs are usually used to cover electrical load peaks. The efficiency of a SGPP can reach 42 - 43%. The most economical are large thermal steam-turbine power plants (abbreviated as TPPs). Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are spent. 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, i.e., 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 jet of steam flows. The steam pressure and temperature are gradually reduced. It is known from the course of physics that the efficiency of heat engines increases with an increase in the initial temperature of the working fluid. Therefore, the steam entering the turbine is brought to high parameters: the temperature is almost up to 550 ° C and the pressure is up to 25 MPa. The efficiency of TPP 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 the water flow is converted into electrical energy. HPP consists of a series circuit hydrotechnical structures, providing the necessary concentration of the water flow and creating pressure, and power equipment that converts the energy of water moving under pressure into mechanical energy of rotation, which, in turn, is converted into electrical energy. The head of the hydroelectric power station is created by the concentration of the fall of the river in the used section by the dam, or derivation, or dam and derivation together. The main power equipment of the HPP is located in the HPP building: in the engine room of the power plant - hydraulic units, auxiliary equipment, automatic control and monitoring devices; in the central control post - the operator-dispatcher console or hydro-electric power plant operator. Boosting transformer substation It is located both inside the HPP building and in separate buildings or in open areas. Distribution devices often located in an open area. The power plant building can be divided into sections with one or more units and auxiliary equipment separated from adjacent parts of the building. At the building of the HPP or inside it, an installation site is created for the assembly and repair of various equipment and for auxiliary maintenance operations of the HPP. By installed capacity (in MW) distinguish between hydroelectric power stations powerful(St. 250), average(up to 25) and small(up to 5). The power of the hydroelectric power station depends on the pressure (the difference between the levels of the upstream and downstream ), the flow rate of water 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, variability in the load of the energy system, repair of hydroelectric units or hydraulic structures, etc.), the pressure and flow of water are constantly changing, and, in addition, the flow rate changes when regulating - power generation of HPPs. There are annual, weekly and daily cycles of the HPP operation mode. According to the maximum used pressure, HPPs are divided into high-pressure(over 60 m), medium pressure(from 25 to 60 m) And low-pressure(from 3 to 25 m). On flat rivers, the pressure rarely exceeds 100 m, in mountainous conditions, through the dam, it is possible to create pressures up to 300 m and more, and with the help of derivation - up to 1500 m. The subdivision of the HPP according to the pressure used is approximate, conditional. According to the scheme for the use of water resources and the concentration of pressures, HPPs are usually divided into channel, near-dam, diversion with pressure and non-pressure derivation, mixed, pumped storage And tidal. In run-of-river and near-dam HPPs, the water pressure is created by a dam that blocks the river and raises the water level in the upstream. At the same time, some flooding of the river valley is inevitable. Run-of-river and near-dam hydroelectric power stations are built both on low-lying high-water rivers and on mountain rivers, in narrow compressed valleys. Run-of-river HPPs are characterized by heads up to 30-40 m. At higher pressures, it turns out to be impractical to transfer hydrostatic water pressure to the power plant building. In this case, the type dam The hydroelectric power station, in which the pressure front is blocked by a dam throughout its entire length, and the building of the hydroelectric power station is located behind the dam, adjoins the downstream. Another kind of layout near the dam The hydroelectric power station corresponds to mountainous conditions with relatively low flow rates of the river. IN derivational Hydroelectric power station concentration of the fall of the river is created by means of derivation; water at the beginning of the used section of the river is diverted from the river channel by a conduit, with a slope significantly less than the average slope of the river in this section and with straightening of the bends and turns of the channel. The end of the derivation is brought to the location of the HPP building. Waste water is either returned to the river or fed to the next derivation HPP. Derivation is beneficial when the slope of the river is high. A special place among HPPs is occupied by pumped storage power plants(PSPP) and tidal power plants(PES). The construction of a pumped storage power plant is due to an increase in the demand for peak power in large energy systems, which determines the generating capacity required to cover peak loads. The ability of the pumped storage power plant to accumulate energy is based on the fact that the electrical energy free in the power system for a certain period of time is used by the pumped storage units, which, operating in pump mode, pump water from the reservoir into the upper storage pool. During load peaks, the accumulated energy is returned to the power system (water from the upper basin enters the pressure pipeline and rotates the hydraulic units operating in the current generator mode). PES convert the energy of sea tides into electrical energy. The electric power of tidal hydroelectric power plants, due to some features associated with the periodic nature of the tides, can be used in power systems only in conjunction with the energy of regulating power plants, which make up for the dips in the power of tidal power plants during the day or months. The most important feature of hydropower resources in comparison with fuel and energy resources is their continuous renewal. The lack of need for fuel for HPPs determines the low cost of electricity generated at HPPs. Therefore, the construction of hydroelectric power stations, despite significant, specific capital investments per 1 kW installed capacity and long construction time, have been and are of great importance, especially when it is associated with the placement of electrically intensive industries. Nuclear power plant (NPP), a power plant in which atomic (nuclear) energy is converted into electrical energy. The power generator at a nuclear power plant is a nuclear reactor. The heat that is released in the reactor as a result of a chain reaction of fission of the nuclei of some heavy elements, then, just like in conventional thermal power plants (TPPs), is converted into electricity. Unlike thermal power plants operating on fossil fuels, nuclear power plants operate on nuclear fire-than(based on 233 U, 235 U, 239 Pu). It has been established that the world energy resources of nuclear fuel (uranium, plutonium, etc.) significantly exceed the energy resources of natural reserves of organic fuel (oil, coal, natural gas and etc.). This opens up broad prospects for meeting the rapidly growing demand for fuel. In addition, it is necessary to take into account the ever-increasing volume of coal and oil consumption for technological purposes of the global chemical industry, which is becoming a serious competitor to thermal power plants. Despite the discovery of new deposits of organic fuel and the improvement of methods for its extraction, there is a tendency in the world to a relative increase in its cost. This creates the most difficult conditions for countries with limited reserves of fossil fuels. There is an obvious need for the rapid development of nuclear power, which already occupies a prominent place in the energy balance of a number of industrial countries of the world. A schematic diagram of a nuclear power plant with a water-cooled nuclear reactor is shown in fig. 2. Heat generated in core reactor coolant, is taken in by water of the 1st circuit, which is pumped through the reactor by a circulation pump. Heated water from the reactor enters the heat exchanger (steam generator) 3, where it transfers the heat received in the reactor to the water of the 2nd circuit. Water from the 2nd circuit evaporates in the steam generator, and steam is formed, which then enters the turbine 4.
Most often, 4 types of thermal neutron reactors are used at nuclear power plants: 1) water-cooled reactors with ordinary water as a moderator and coolant; 2) graphite-water with water coolant and graphite moderator; 3) heavy water with a water coolant and heavy water as a moderator; 4) 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 materials, etc. The reactor and its servicing systems include: the reactor itself with biological protection , heat exchangers, pumps or gas blowers that circulate the coolant, pipelines and fittings for the circulation of the circuit, 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 protection, the main material for which are concrete, water, serpentine sand. The reactor circuit equipment must be completely sealed. A system is provided for monitoring places of possible leakage of the coolant, measures are taken so that the appearance of leaks and breaks in the circuit does not lead to radioactive emissions and pollution of the NPP premises and the surrounding area. Radioactive air and a small amount of coolant vapor, due to the presence of leaks from the circuit, are removed from unattended NPP premises by a special ventilation system, in which cleaning filters and holding gas holders are provided to eliminate the possibility of atmospheric pollution. The dosimetric control service monitors the fulfillment of the radiation safety rules by the NPP personnel. Availability biological protection, special ventilation and emergency cooling systems and dosimetric control services allows you to completely secure service staff NPP from the harmful effects of radioactive exposure. Nuclear power plants, which are the most modern type of power plants, have a number of significant advantages over other types of power plants: under normal operating conditions, they absolutely do not pollute the environment, do not require binding to a source of raw materials and, accordingly, can be placed almost anywhere. The new power units have a capacity almost equal to the capacity of an average hydroelectric power plant, but the installed capacity utilization factor at nuclear power plants (80%) is significantly higher than that of hydroelectric power plants or thermal power plants. There are practically no significant drawbacks of nuclear power plants under normal operating conditions. However, one cannot fail to notice the danger of nuclear power plants under possible force majeure circumstances: earthquakes, hurricanes, etc. - here old models of power units pose a potential danger of radiation contamination of territories due to uncontrolled overheating of the reactor.

Alternative energy sources.

Energy of sun. Recently, interest in the problem of using solar energy has increased dramatically, because the potential for energy based on the use of direct solar radiation is extremely high. The simplest collector of solar radiation is a blackened metal (usually aluminum) sheet, inside of which there are pipes with a liquid circulating in it. Heated by solar energy absorbed by the collector, the liquid is supplied for direct use. Solar energy is one of the most material-intensive types of energy production. The large-scale use of solar energy entails a gigantic increase in the need for materials, and, consequently, for labor resources for the extraction of raw materials, their enrichment, the production of materials, the manufacture of heliostats, collectors, other equipment, and their transportation. So far, the electrical energy generated by the sun's rays is much more expensive than that obtained by traditional methods. The scientists hope that the experiments that they will carry out at experimental facilities and stations will help to solve not only technical, but also economic problems. wind energy. The energy of moving air masses is enormous. The reserves of wind energy are more than a hundred times greater than the reserves of hydropower of all the rivers of the planet. Winds blow constantly and everywhere on earth. Climatic conditions allow the development of wind energy in a vast area. But these days, wind-powered engines cover only one-thousandth of the world's energy needs. Therefore, specialists in aircraft construction are involved in the creation of the designs of the wind wheel, the heart of any wind power plant, who are able to choose the most appropriate blade profile and explore it in a wind tunnel. Through the efforts of scientists and engineers, a wide variety of designs of modern wind turbines have been created. Earth energy. Since ancient times, people have known about the spontaneous manifestations of gigantic energy lurking in the bowels of the globe. The memory of mankind keeps legends about catastrophic volcanic eruptions that claimed millions of human lives, unrecognizably changed the appearance of many places on Earth. The power of the eruption of even a relatively small volcano is colossal, it many times exceeds the power of the largest power plants created by human hands. True, there is no need to talk about the direct use of the energy of volcanic eruptions, so far people do not have the opportunity to curb this recalcitrant element. The energy of the Earth is suitable not only for heating rooms, 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 quite low-power, was built in 1904 in the small Italian town of Larderello. Gradually, the capacity of the power plant grew, more and more new units came 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.

Electricity transmission.

Transformers.

You have purchased a ZIL refrigerator. The seller warned you that the refrigerator is designed for a mains voltage of 220 V. And in your house the mains voltage is 127 V. A stalemate? Not at all. You just have to make an additional cost and purchase a transformer. Transformer- a very simple device that allows you to both increase and decrease the voltage. AC conversion is carried out using transformers. For the first time, transformers were used in 1878 by the Russian scientist P.N. Yablochkov to power the “electric candles” he invented, a new light source at that time. The idea of P. N. Yablochkov was developed by an employee of the Moscow University I. F. Usagin, who designed improved transformers. The transformer consists of a closed iron core, on which two (sometimes more) coils with wire windings are put on (Fig. 1) . One of the windings, called the primary, is connected to an alternating voltage source. The second winding, to which the "load" is connected, i.e. devices and devices that consume electricity, is called secondary.

Fig.1 Fig.2

The diagram of the device of a transformer with two windings is shown in Figure 2, and the symbol adopted for it is in Figure. 3.

The action of the transformer is based on the phenomenon of electromagnetic induction. When an alternating current passes through the primary winding, an alternating magnetic flux appears in the iron core, which excites the induction EMF in each winding. Moreover, the instantaneous value of the induction emf e in any turn of the primary or secondary winding according to Faraday's law is determined by the formula:

e = -Δ F/Δ t

If F= Ф 0 сosωt, then e \u003d ω F 0 sinω t, or e =E 0 sinω t , where E 0 \u003d ω Ф 0 - the amplitude of the EMF in one turn. In the primary winding, which has P 1 turns, total emf induction e 1 is equal to P 1 e. There is total EMF in the secondary winding. e 2 is equal to P 2 e, where P 2 - number of turns of this winding.

Hence it follows that

e 1 e 2 = P 1 P 2 . (1) Voltage sum u 1 , applied to the primary winding, and the EMF e 1 should be equal to the voltage drop in the primary winding: u 1 + e 1 = i 1 R 1 , where R 1 is the active resistance of the winding, and i 1 is the current in it. This equation follows directly from the general equation. Usually the active resistance of the winding is small and a member i 1 R 1 can be neglected. That's why u 1 ≈ - e 1 . (2) When the secondary winding of the transformer is open, no current flows in it, and the relation holds:

u 2 ≈ - e 2 . (3)

Since the instantaneous values of the emf e 1 And e 2 change in phase, then their ratio in formula (1) can be replaced by the ratio of effective values E 1 AndE 2 these EMF or, taking into account equalities (2) and (3), the ratio of the effective voltage values U 1 and U 2 .

U 1 /U 2 = E 1 / E 2 = n 1 / n 2 = k. (4)

Value k called the transformation ratio. If k>1, then the transformer is step-down, with k<1 - increasing. When the circuit of the secondary winding is closed, current flows in it. Then the relation u 2 ≈ - e 2 is no longer fulfilled exactly, and, accordingly, the connection between U 1 and U 2 becomes more complex than in equation (4). According to the law of conservation of energy, the power in the primary circuit must be equal to the power in the secondary circuit: U 1 I 1 = U 2 I 2, (5)where I 1 And I 2 - effective values of force in the primary and secondary windings.

Hence it follows that

U 1 /U 2 = I 1 / I 2 . (6)

This means that by increasing the voltage several times with the help of a transformer, we reduce the current by the same amount (and vice versa).

Due to the inevitable energy losses for heat generation in the windings and the iron core, equations (5) and (6) are fulfilled approximately. However, in modern high-power transformers, the total losses do not exceed 2-3%.

Welding machines require step-down transformers. Welding requires very high currents, and the transformer of the welding machine has only one output turn.

At home you are dealing with small transformers. As for powerful transformers, they are huge structures. In these cases, the core with windings is placed in a tank filled with cooling oil.

Electricity transmission

Q=I 2 Rtwhere R is the line resistance. With a long line, the transmission of energy can become generally economically unprofitable. To reduce losses, you can, of course, follow the path of reducing the resistance R of the line by increasing the cross-sectional area of \u200b\u200bthe wires. But to reduce R, for example, by a factor of 100, the mass of the wire must also be increased by a factor of 100. It is clear that such a large expenditure of expensive non-ferrous metal cannot be allowed, not to mention the difficulties of fixing heavy wires on high masts, etc. Therefore, energy losses in the line are reduced in another way: by reducing the current in the line. For example, a decrease in current by a factor of 10 reduces the amount of heat released in the conductors by 100 times, i.e., the same effect is achieved as from a hundredfold weighting of the wire.

Therefore, step-up transformers are installed at large power plants. The transformer increases the voltage in the line as many times as it reduces the current. The power loss in this case is small.

For the direct use of electricity in the motors of the electric drive of machine tools, in the lighting network and for other purposes, the voltage at the ends of the line must be reduced. This is achieved with the help of step-down transformers. Moreover, usually a decrease in voltage and, accordingly, an increase in current strength occurs in several stages. At each stage, the voltage is getting smaller, and the area covered by the electrical network is getting wider. The scheme of transmission and distribution of electricity is shown in the figure.

The use of electricity.

The use of electric power in various fields of science.

The 20th century has become a century when science invades all spheres of society: economy, politics, culture, education, etc. Naturally, science directly affects the development of energy and the scope of electricity. On the one hand, science contributes to the expansion of the scope of electrical energy and thereby increases its consumption, but on the other hand, in an era when the unlimited use of non-renewable energy resources poses a danger to future generations, the development of energy-saving technologies and their implementation in life become topical tasks of science. Let's consider these questions on concrete examples. About 80% of GDP growth (gross domestic product) in developed countries is achieved through technical innovation, most 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 start with theoretical calculations. But if in the 19th century these calculations were made using pen and paper, then in the age of scientific and technical revolution (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, the most convenient for its transmission over a distance and use. But if initially computers were used for scientific calculations, now computers have come to life from science. Now they are used in all areas of human activity: for recording and storing information, creating archives, preparing and editing texts, performing drawing and graphic work, automating production and agriculture. Electronization and automation of production are the most important consequences of the "second industrial" or "microelectronic" revolution in the economies of developed countries. The development of integrated automation is directly related to microelectronics, a qualitatively new stage of which began after the invention in 1971 of the microprocessor - a microelectronic logic device built into various devices to control their operation. Microprocessors have accelerated the growth of robotics. Most of the robots in use today belong to the so-called first generation, and are used in welding, cutting, pressing, coating, etc. The second-generation robots that replace them are equipped with devices for recognizing the environment. And robots - "intellectuals" of the third generation will "see", "feel", "hear". Scientists and engineers call nuclear energy, space exploration, transport, trade, warehousing, medical care, waste processing, and the development of the wealth of the ocean floor among the most priority areas for the use of robots. The majority of robots run on electrical energy, but the increase in robot electricity consumption is offset by the reduction in energy costs in many energy-intensive manufacturing processes through the introduction of smarter methods and new energy-saving technological processes. But back to science. All new theoretical developments are verified experimentally after computer calculations. And, as a rule, at this stage, research is carried out using physical measurements, chemical analyzes, etc. Here, scientific research tools are diverse - numerous measuring instruments, accelerators, electron microscopes, magnetic resonance tomographs, etc. Most of these instruments of experimental science run on electrical energy. Science in the field of communications and communications is developing very rapidly. Satellite communication is used not only as a means of international communication, but also in everyday life - satellite dishes are not uncommon in our city. New means of communication, such as fiber technology, can significantly reduce the loss of electricity in the process of transmitting signals over long distances. Science and the sphere of management did not bypass. As the scientific and technological revolution develops, the production and non-production spheres of human activity expand, management begins to play an increasingly important role in improving their efficiency. From a kind of art, until recently based on experience and intuition, management has now become a science. The science of management, the general laws of receiving, storing, transmitting and processing information is called cybernetics. This term comes from the Greek words "helmsman", "helmsman". It is found in the writings of ancient Greek philosophers. However, its new birth actually took place in 1948, after the publication of the book "Cybernetics" by the American scientist Norbert Wiener. Before the beginning of the "cybernetic" revolution, there was only paper computer science, the main means of perception of which was the human brain, and which did not use electricity. The "cybernetic" revolution gave rise to a fundamentally different - machine informatics, corresponding to the gigantically increased flows of information, the source of energy for which is electricity. Completely new means of obtaining information, its accumulation, processing and transmission have been created, which together form a complex information structure. It includes automatic control systems (automated control systems), information data banks, automated information bases, computer centers, video terminals, copiers and telegraph machines, nationwide information systems, satellite and high-speed fiber-optic communication systems - all this has unlimitedly expanded the scope of electricity use. Many scientists believe that in this case we are talking about a new "information" civilization, replacing the traditional organization of an industrial type of society. This specialization is characterized by the following important features:

widespread use of information technology in material and non-material production, in the field of science, education, healthcare, etc.; the presence of a wide network of various data banks, including public use; transformation of information into one of the most important factors of economic, national and personal development; free circulation of information in society. Such a transition from an industrial society to an "information civilization" became possible largely due to the development of energy and the provision of a convenient type of energy in transmission and use - electrical energy.

Electricity in production.

Electricity in the home.

Electricity in everyday life is an essential assistant. Every day we deal with it, and, probably, we can no longer imagine our life without it. Remember the last time you turned off the light, that is, your house did not receive electricity, remember how you swore that you didn’t have time for anything and you needed light, you needed a TV, a kettle and a bunch of other electrical appliances. After all, if we are de-energized forever, then we will simply return to those ancient times when food was cooked on a fire and lived in cold wigwams. The importance of electricity in our life can be covered with a whole poem, it is so important in our life and we are so used to it. Although we no longer notice that she comes to our homes, but when she is turned off, it becomes very uncomfortable. Appreciate electricity!

Bibliography.

Textbook by S.V. Gromov "Physics, Grade 10". Moscow: Enlightenment. Encyclopedic Dictionary of a Young Physicist. Composition. V.A. Chuyanov, Moscow: Pedagogy. Allion L., Wilcons W.. Physics. Moscow: Nauka. Koltun M. World of Physics. Moscow. Energy sources. Facts, problems, solutions. Moscow: Science and technology. Non-traditional energy sources. Moscow: Knowledge. Yudasin L.S. Energy: problems and hopes. Moscow: Enlightenment. Podgorny A.N. Hydrogen energy. Moscow: Nauka.abstract

One of the biggest problems solved during the period under consideration was the production and use of electricity - the new energy basis for industry and transport.

abstract

The history of electric lighting began in 1870 with the invention of the incandescent lamp, in which light was produced as a result of an electric current.

abstract

In the middle of the 19th century, the history of science and technology approached a critical period, when the main efforts of leading scientists and inventors - electrical engineers in many countries focused on one direction: the creation of more convenient light sources.

Document

Among the most interesting and mysterious phenomena of nature, children's giftedness occupies one of the leading places. The problems of its diagnosis and development have been of concern to educators for many centuries.

Sangadzhieva Lyubov Batovna, teacher of physics, the highest qualification category. Moscow 2011 work program

Working programm

This work program in physics for grades 10-11 is based on the federal component of the state standard for secondary (complete) general education in physics (2004).