Alternating voltage can be converted - increased or decreased.
Devices that can be used to convert voltageare called transformers. The operation of transformers is based on the phenomenon of electromagnetic induction.
Transformer device
The transformer consists of ferromagnetic core on which two coils are placed.
The primary winding is called coil connected to an alternating voltage source U 1 .
The secondary winding is called a coil that can be connected to devices that consume electrical energy.
Devices that consume electrical energy act as a load, and an alternating voltage U is created across them 2 .
If U 1 >U 2 , That the transformer is called a step-down transformer, and if U 2 >U 1 - then increasing.
Principle of operation
An alternating current is created in the primary winding, therefore, an alternating magnetic flux is created in it. This flux is closed in the ferromagnetic core and penetrates each turn of both windings. In each of the turns of both windings the same induced emf appearse i 0
If n 1 and n 2 are the number of turns in the primary and secondary windings, respectively, then
Induction EMF in the primary winding e i 1 = n 1 * e i 0 Induction EMF in the secondary winding e i 2 = n 1 * e i 0
Wheree i 0 - Induction emf arising in one turn of the secondary and primary coil .
Electricity transmission
P 
transmission electrical energy from power plants to large cities or industrial centers over distances of thousands of kilometers is a complex scientific and technical problem. Energy (power) losses for heating wires can be calculated using the formula
To reduce losses due to heating of wires, it is necessary to increase the voltage. Typically, power lines are built for a voltage of 400–500 kV, while in lines alternating current with a frequency of 50 is used Hz The figure shows a diagram of the electricity transmission line from the power plant to the consumer. The diagram gives an idea of the use of transformers in power transmission
41. Electromagnetic field and electromagnetic waves. Speed of electromagnetic waves. Properties of electromagnetic waves. Ideas of Maxwell's theory
Existence electromagnetic waves was theoretically predicted by the great English physicist J. Maxwell in 1864. Maxwell introduced the concept into physics vortex electric field and proposed a new interpretation of the law electromagnetic induction, discovered by Faraday in 1831:
Any change in the magnetic field generates a vortex electric field in the surrounding space .
Maxwell hypothesized the existence of the reverse process:
A time-varying electric field generates a magnetic field in the surrounding space.
Once begun, the process of mutual generation of magnetic and electric fields must then continue continuously and capture more and more new areas of space.
Conclusion:
There is a special form of matter – electromagnetic field – which consists of vortex electric and magnetic fields generating each other.
The electromagnetic field is characterized two vector quantities - tensionE vortex electric field and inductionIN magnetic field.
The process of propagation of changing vortex electric and magnetic fields in space is calledelectromagnetic wave.
Maxwell's hypothesis was only a theoretical assumption that did not have experimental confirmation, but on its basis Maxwell managed to write down a consistent system of equations describing the mutual transformations of electric and magnetic fields, i.e., a system of equations electromagnetic field(Maxwell's equations)
Video tutorial 2: AC problems
Lecture: Alternating current. Production, transmission and consumption of electrical energy
Alternating currentAlternating current- these are oscillations that can occur in a circuit as a result of connecting it to a source AC voltage.
It is alternating current that surrounds us all - it is present in all circuits in apartments, and transmission through wires occurs precisely of alternating voltage current. However, almost all electrical appliances operate on constant electricity. That is why, at the outlet of the outlet, the current is rectified and passes into household appliances in the form of a constant current.
It is alternating current that is easiest to receive and transmit over any distance.
When studying alternating current we will use a circuit in which we will connect a resistor, a coil and a capacitor. In this circuit, the voltage is determined in law:
As we know, sine can be negative and positive. That is why the voltage value can take different directions. When the current flow is positive (counterclockwise), the voltage is greater than zero; when the current is negative, it is less than zero.
Resistor in a circuit
So, let's consider the case when only a resistor is connected to an alternating current circuit. The resistance of a resistor is called active. We will consider the current that flows counterclockwise through the circuit. In this case, both current and voltage will have a positive value.
To determine the current in a circuit, use the following formula from Ohm's law:
In these formulas I 0 And U 0 - maximum current and voltage values. From this we can conclude that maximum value current is equal to the ratio of the maximum voltage to the active resistance:
These two quantities change in the same phase, so the graphs of the quantities have the same appearance, but different amplitudes.
Capacitor in a circuit
Remember! Unable to receive D.C. in the circuit where there is a capacitor. It is a place for breaking the flow of current and changing its amplitude. In this case, alternating current flows perfectly through such a circuit, changing the polarity of the capacitor.
When considering such a circuit, we will assume that it contains only a capacitor. The current flows counterclockwise, that is, it is positive.
As we already know, the voltage on a capacitor is related to its ability to accumulate charge, that is, its size and capacity.
Since the current is the first derivative of the charge, it can be determined by what formula it can be calculated by finding the derivative of the last formula:
As you can see, in this case the current strength is described by the law of cosine, while the value of voltage and charge can be described by the law of sine. This means that the functions are in the opposite phase and have a similar appearance on the graph.
We all know that the cosine and sine functions of the same argument differ by 90 degrees from each other, so we can get the following expressions:
From here, the maximum current value can be determined by the formula:
The value in the denominator is the resistance across the capacitor. This resistance is called capacitive. It is located and designated as follows:
As capacitance increases, the amplitude value of the current decreases.
Please note that in this circuit, the use of Ohm's law is appropriate only in the case when it is necessary to determine the maximum value of the current; it is impossible to determine the current at any time using this law due to the difference in the phases of the voltage and current strength.
Coil in a chain
Consider a circuit that has a coil. Let's imagine that it has no active resistance. In this case, it would seem that nothing should interfere with the flow of current. However, it is not. The thing is that when current passes through the coil, a vortex field begins to arise, which prevents the passage of current as a result of the formation of a self-induction current.
The current strength takes the following value:
Again, you can see that the current changes according to the cosine law, so for this circuit there is a phase shift, which can be seen on the graph:
Hence the maximum current value:
In the denominator we can see the formula that determines the inductive reactance of the circuit.
The greater the inductive reactance, the smaller the current amplitude.
Coil, resistance and capacitor in a circuit.
If all types of resistance are simultaneously present in the circuit, then the current value can be determined as follows by transforming Ohm's law:
The denominator is called total resistance. It consists of the sum of the squares of active (R) and reactance, consisting of capacitive and inductive. The total resistance is called "Impedance".
Electricity
It is impossible to imagine modern life without using electrical appliances, which work due to the energy generated by electric current. All technological progress is based on electricity.
Getting energy from electric current has a huge number of advantages:
1. Electric current is quite easy to produce, since there are billions of power plants, generators and other devices for generating electricity around the world.
2. Electricity can be transmitted over vast distances in a short time and without significant losses.
3. It is possible to convert electrical energy into mechanical, light, internal and other types.
| | |
BOU of the Chuvash Republic SPO "ASHT" Ministry of Education of Chuvashia
METHODOLOGICAL
DEVELOPMENT
open lesson in the discipline "Physics"
Topic: Production, transmission and consumption of electrical energy
highest qualification category
Alatyr, 2012
REVIEWED
at a meeting of the methodological commission
humanities and natural sciences
disciplines
Protocol No. __ dated “___” ______ 2012
Chairman_____________________
Reviewer: Ermakova N.E., teacher of the Chechen State Educational Institution of Secondary Professional Education “ASHT”, Chairman of the PCC of Humanities and Natural Sciences
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 types energy, a person is not able to fully exist. It is difficult to imagine the existence of modern civilization without electricity. If the light in our apartment goes out for even a few minutes, then we already experience numerous inconveniences. What happens if there is a power outage for several hours? Electric current is the main source of electricity. This is why it is so important to understand the physics of receiving, transmitting, and using alternating electric current.
Explanatory note
Contents of the main part
Bibliography
Applications.
Explanatory note
Goals:
- introduce students to the physical foundations of production, transmission and
use of electrical energy
To contribute to the formation of information and communication skills in students
competencies
Deepen knowledge about the development of the electric power industry and related environmental issues
problems, fostering a sense of responsibility for preserving the environment
Justification for the chosen topic:
It is impossible to imagine our life without electrical energy today. Electric power has invaded all spheres of human activity: industry and agriculture, science and space. Our life is unthinkable without electricity. Electricity has been and remains the main component of human life. What will the energy sector of the 21st century be like? To answer this question, you need to know the main methods of generating electricity, study the problems and prospects modern production electricity 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 theoretical knowledge in practice, to develop the skills of independent work with various sources of information. This lesson reveals the possibilities of developing information and communication competencies
Lesson plan
in the discipline "Physics"
Date: 04/16/2012
Group: 11 TV
Goals:
- educational: - introduce students to the physical foundations of production,
transmission and use of electrical energy
To 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 preserving the environment
- developing:: - develop skills to process information and apply
knowledge of theory in practice;
Develop skills of independent work with various
sources of information
Develop cognitive interest in the subject.
- educational:
- to foster cognitive activity of students;
Develop the ability to listen and be heard;
To foster students’ independence in acquiring new
knowledge
- develop communication skills when working in groups
Task: formation key competencies when studying the production, transmission and use of electrical energy
Type of activity- lesson
Type of activity- combined lesson
Means of education: textbooks, reference books, Handout, multimedia projector,
screen, electronic presentation
Progress of the lesson:
Organizational moment (checking absentees, group readiness for the lesson)
Organization of the target space
Testing students' knowledge, communicating the topic and plan of the survey, setting a goal
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Teacher's actions |
Student actions |
Methods |
2) What device is used to change the 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 and which step-down? 8) What is the power of a transformer called?
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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 learning new material
Topic: “Production, transmission and consumption of electricity”
Plan: 1) Electricity production:
a) Industrial energy (hydroelectric power station, thermal power plant, nuclear power plant)
b) Alternative energy (Geothermal power plant, solar power plant, wind power plant, thermal power plant)
2) Electrical energy transmission
3) Efficient use of electrical energy
4) Energy of the Chuvash Republic
Motivation for students' educational activities
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Teacher's actions |
Student actions |
Study method |
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Advanced independent work Study Student reports |
Consolidating new material
Generalization and systematization of the material.
Conducting a summary of the lesson.
Assignment for independent work of students during extracurricular time.
Textbook § 39-41, finish filling out the table
It is impossible to imagine our life without electrical energy today. Electric power has invaded all spheres of human activity: industry and agriculture, science and space. Our life is unthinkable without electricity. Such a widespread use of electricity is explained by its advantages over other types of energy. Electricity has been and remains the main component of human life. The main questions are: how much energy does humanity need? What will the energy sector of the 21st century be like? To answer these questions, 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.
The conversion of various types of energy into electrical energy occurs at power plants. Let's consider the physical basis of electricity production at power plants.
Statistical data on electricity production in Russia, billion kWh
Depending on the type of energy converted, power plants can be divided into the following main types:
Industrial power plants: hydroelectric power stations, thermal power plants, nuclear power plants
Alternative energy power plants: thermal power plant, solar power plant, wind power plant, geothermal power plant
Hydroelectric power plants
A hydroelectric power station is a complex of structures and equipment through which the energy of water flow is converted into electrical energy. At a hydroelectric power station, electricity is produced using the energy of water flowing from top level To lower level and rotating the turbine. The dam is the most important and most expensive element of a hydroelectric power station. Water flows from the upstream to the downstream through special pipelines or through channels made in the body of the dam and acquires greater speed. A stream of water flows onto the blades of a hydraulic turbine. The rotor of a hydraulic turbine is driven into rotation under the action of the centrifugal force of a stream of water. The turbine shaft is connected to the shaft of the 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 compared to fuel and energy resources is their continuous renewability. The absence of fuel requirement for hydroelectric power plants determines the low cost of electricity generated by hydroelectric power plants. However, hydropower is not environmentally friendly. When a dam is built, a reservoir is formed. Water that has flooded vast areas irreversibly changes environment. Raising the river level by a dam can cause waterlogging, salinity, and changes in riparian vegetation and microclimate. That is why 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 heating or combined heat and power plants (CHP). Condensing stations supply consumers only with electrical energy. They are built near deposits of local fuel so as not to transport it over long distances. Heating plants supply consumers not only with electrical energy, but also with heat - water vapor or hot water, therefore, thermal power plants are built close to heat receivers, in the centers of industrial areas and large cities to reduce the length of heating networks. Fuel is transported to thermal power plants from its production sites. A boiler with water is installed in the turbine room of the thermal power plant. 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 a steam turbine through a steam pipeline, the purpose of which is to transform thermal energy steam into mechanical energy. The energy of movement of a 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 at low pressure and a temperature of about 25°C, enters the condenser. Here the steam is converted into water with the help of cooling water, which is again supplied to the boiler using a pump. The cycle begins again. Thermal power plants operate on fossil fuels, but, unfortunately, these are irreplaceable natural resources. In addition, the operation of thermal power plants is accompanied by environmental problems: When fuel burns, 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 atomic (nuclear) energy is converted into electrical energy. Nuclear power plants operate on the same principle as thermal power plants, but for vaporization they use the energy obtained from the fission of heavy atomic nuclei(uranium, plutonium). Nuclear reactions occur in the reactor core, accompanied by the release of enormous energy. 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 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 a turbine, which converts the thermal energy of the steam into mechanical energy. The energy of movement of a 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 look power plants have a number of significant advantages over other types of power plants: they do not require connection to a source of raw materials and, in fact, can be located anywhere; under normal operating conditions they are considered environmentally friendly. But in case of accidents at nuclear power plants, there is a potential danger of radiation contamination of the environment. In addition, disposal of radioactive waste and dismantling of old nuclear power plants remains 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 harming the ecology of the area. An alternative energy source is a method, device or structure that makes it possible to obtain electrical energy (or other required type of energy) and replaces traditional energy sources that operate on oil, extracted natural gas and coal. The purpose of searching for alternative energy sources is the need to obtain it from renewable or practically inexhaustible energy 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 rises under the influence of the gravitational forces of the Moon and the Sun, attracting masses of water. Far from the shore, water level fluctuations do not exceed 1 m, but near the shore they can reach 13-18 meters. To set up a simple tidal power plant (TPP), you need a pool - a dammed bay or a river mouth. The dam has culverts and installed hydraulic turbines 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, turbines operate by moving water from the sea to the basin and back. Double-acting 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 operating time of turbines, there are more complex circuits– with two, three or 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 seas and oceans, moreover, they do not develop very much 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 thereby the living conditions of marine flora and fauna. They also influence the climate, since they change the energy potential of sea waters, their speed and area of movement.
Wind power plants
Wind energy is an indirect form of solar energy, resulting from differences in temperature and pressure in the Earth's atmosphere. About 2% of solar energy reaching the Earth is converted into wind energy. Wind is a renewable energy source. Its energy can be used in almost all areas of the Earth. Generating electricity from wind power plants is extremely attractive, but at the same time technically challenging. The difficulty lies in the very large dissipation of wind energy and its inconstancy. The principle of operation of wind power plants is simple: the wind rotates the blades of the installation, driving the shaft of the electric generator. The generator produces electrical energy and thus the wind energy is converted into electrical current. Wind farms are very cheap to produce, but their power is low and their operation is dependent on the weather. In addition, they are very noisy, so large installations even have to be turned off at night. Besides, wind power plants interfere with air traffic and even radio waves. The use of wind power plants causes a local weakening of the strength of air flows, which interferes with the ventilation of industrial areas and even affects the climate. Finally, to use wind power plants, huge areas are required, much larger than for other types of electric generators. And yet, isolated wind farms with heat engines as a reserve and wind farms that operate in parallel with thermal and hydroelectric power plants should take a prominent place in the energy supply of those areas where wind speeds exceed 5 m/s.
Geothermal power plants
Geothermal energy is energy internal regions Earth. Volcanic eruptions clearly demonstrate the enormous heat inside the planet. Scientists estimate the temperature of the Earth's core to be thousands of degrees Celsius. Geothermal heat– this is the heat contained in underground hot water and water vapor, and the heat of heated dry rocks. Geothermal thermal power plants (GEP) transform internal heat Earth (energy from hot steam-water sources) into electrical energy. Sources geothermal energy there may be underground pools of natural coolants – hot water or a couple. Essentially, these are ready-to-use "underground boilers" from which water or steam can be extracted using conventional boreholes. The natural steam obtained in this way, after preliminary purification from gases that cause pipe destruction, is sent to turbines connected to electric generators. The use of geothermal energy does not require large costs, because in this case we are talking about “ready-to-use” energy sources created by nature itself. The disadvantages of geothermal power plants include the possibility of local subsidence of soil and the awakening of seismic activity. And the gases coming out of the ground create considerable noise in the surrounding area and may, moreover, contain toxic substances. In addition, geothermal power plants cannot be built everywhere, because geological conditions are required for its construction.
Solar power plants
Solar energy is the most ambitious, cheapest, but also, perhaps, the least used source of energy by humans. The conversion of solar radiation energy into electrical energy is carried out using 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 uninterruptedly supply electricity to river buoys, signal lights, emergency communication systems, lighthouse lamps and many other objects located in hard to reach places. As we improve solar panels they will find application in residential buildings for autonomous power supply (heating, hot water supply, lighting and power supply of household electrical appliances). Solar power plants have a noticeable advantage over other types of stations: the absence of harmful emissions and environmental friendliness, quiet operation, and preservation of the integrity of the earth's interior.
Transmission of electricity over a distance
Electricity is produced close to sources of fuel or water resources, while its consumers are located everywhere. Therefore, there is a need to transmit electricity over long distances. Let's consider a schematic diagram of the transmission of electricity from a generator to a consumer. Typically, alternating current generators at power plants produce a voltage not exceeding 20 kV, since at higher voltages the possibility of electrical breakdown of insulation in the winding and in other parts of the generator increases sharply. To maintain the transmitted power, the voltage in the power lines must be maximum, which is why step-up transformers are installed at large power plants. However, the voltage in the power line is limited: when too high voltage Discharges occur between the wires, leading to energy loss. To use electricity for industrial enterprises a significant reduction in voltage is required, carried out using step-down transformers. A further reduction in voltage to a value of about 4 kV is necessary for power distribution along local networks, i.e. along those 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 expenses of every family. Her efficient use will significantly reduce costs. Increasingly, computers are being installed in our apartments, dishwashers, Food processors. Therefore, the payment for electricity is very significant. Increased energy consumption leads to additional consumption of non-renewable natural resources: coal, oil, gas. When fuel is burned, it releases into the atmosphere carbon dioxide, which leads to harmful climate change. Saving electricity allows you to reduce the consumption of natural resources, and therefore reduce emissions harmful substances in atmosphere.
Four stages 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 (batteries with valve).
The energy sector 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 tightly connected with the daily life of every enterprise, institution, firm, house, every apartment and, ultimately, every resident of our republic.
At the very beginning of the 20th century, when the electric power industry was just taking its first practical steps.
Until 1917 There was not a single public power station on the territory of modern Chuvashia. Peasant houses were illuminated by a torch.
There were only 16 prime movers in industry. In Alatyr district, electricity was produced and used at sawmills and flour mills. There was a small power plant at a distillery near Marposad. The Talantsev merchants had their own power plant at the oil mill in Yadrino. In Cheboksary, the merchant Efremov owned 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 construction of public power plants begins, unfolds big job for the creation of electric power in Alatyr. At that time, they decided to build the first power plant at the former Popov plant.
In Cheboksary, electrification issues were dealt with by the public utilities department. Through his efforts in 1918 The power plant at the sawmill, owned by the merchant Efremov, resumed operation. Electricity was supplied through two lines to government offices 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. Due to the urgent need, the regional department of public utilities equipped the first small power station in Cheboksary, with a capacity of 12 kW.
The Mariinsko-Posad power plant was equipped in 1919. The Marposad city power plant began to provide electricity. The Tsivilskaya power plant was built in 1919, but due to the lack of power lines, electricity supply began only in 1923.
Thus, the first foundations of Chuvashia’s energy sector were laid during the years of intervention and civil war. The first small urban communal 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 public power station on the territory of Chuvashia; the houses were ruled by torch. They even worked in small workshops using a torch or kerosene lamp. Here artisans used mechanically driven equipment. At more established enterprises, where agricultural and forestry 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 industry of Chuvashia. In this small town, thanks to the efforts of the local economic council, the first public power plant appeared.
In Cheboksary, all electrification in 1918 boiled down to the restoration of the power plant at the sawmill confiscated from the merchant Efremov, which became known as “Named on October 25.” However, its electricity was only enough to illuminate some streets and government institutions (according to statistics, in 1920, city officials had about 100 light bulbs with a power of 20 candles).
In 1924, three more small power plants were built, and, to manage the increasing energy base, the Chuvash Association of Utility Power Plants - CHOKES - was created on October 1, 1924. In 1925, the State Planning Committee of the Republic adopted an electrification plan, which provided for the construction of 8 new power plants over 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 the republic's municipal and industrial power plants increased almost 10 times; Electricity production from these power plants increased almost 30 times.
During the Great Patriotic War Large measures were taken to strengthen and develop the energy base of the republic's industry. The growth in capacity occurred mainly due to the growth in the capacity of regional, municipal and rural power plants. The energy workers of Chuvashia passed the difficult test with honor and fulfilled their patriotic duty. They understood that the electricity produced was needed, first of all, by enterprises fulfilling orders from the front.
During the years of the post-war five-year plan, 102 rural power plants were built and put into operation in the Chuvash Autonomous Soviet Socialist Republic, incl. 69 hydroelectric power stations and 33 thermal power plants. The supply of electricity to agriculture has increased 3 times compared to 1945.
In 1953, in Alatyr, by order signed by Stalin, the construction of the Alatyr thermal power plant began. The first turbogenerator with a capacity of 4 MW was put into operation in 1957, the second - in 1959. According to forecasts, the power of the thermal power plant should have been sufficient until 1985 for both the city and the region and would have provided electricity to the Turgenevsky Light Factory in Mordovia.
Bibliography
Textbook by S.V. Gromov “Physics, 10th grade”. Moscow: Enlightenment.
Encyclopedic dictionary of a young physicist. Compound. V.A. Chuyanov, Moscow: Pedagogy.
Ellion L., Wilcons W.. Physics. Moscow: Science.
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: Science.
Application
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Power station |
Primary energy source |
Conversion circuit energy |
Advantages |
Flaws |
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GeoTES |
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Complete the sentence: The energy system is
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Power grid - The electrical system of the country's regions, connected by high-voltage power lines |
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What is the source of energy in hydroelectric power plants?
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What energy sources - renewable or non-renewable - are used in the Republic of Chuvashia? |
Non-renewable |
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Place in chronological order energy sources that became available to humanity, starting from the earliest: A. Electric traction; B. Nuclear energy; B. Muscular energy of domestic animals; D. Steam energy. |
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Name the sources of energy known to you, the use of which will lead to a decrease environmental consequences electric power industry. |
PES GeoTES |
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Check yourself on the answers on the screen and give a rating: 5 correct answers – 5 4 correct answers – 4 3 correct answers - 3 |
in physics
on the topic “Production, transmission and use of electricity”
11th grade A students
Municipal educational institution No. 85
Catherine.
Abstract plan.
Introduction.
1. Electricity production.
1. types of power plants.
2. alternative energy sources.
2. Electricity transmission.
- transformers.
3. Electricity use.
Introduction.
The birth of energy occurred several million years ago, when people learned to use fire. Fire gave them warmth and light, was a source of inspiration and optimism, a weapon against enemies and wild animals, a healing agent, an assistant in agriculture, a food preservative, a technological tool, etc.
The wonderful myth about Prometheus, who gave people fire, appeared in Ancient Greece much later than in many parts of the world quite sophisticated methods of handling fire, its production and extinguishing, preserving fire and rational use fuel.
For many years, fire was maintained by burning plant energy sources (wood, shrubs, reeds, grass, dry algae, etc.), and then the possibility of using fossil substances to maintain fire was discovered: 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, thermal power plants were the main type of power plants.
In thermal power plants, the chemical energy of the fuel is converted first into mechanical energy and then into electrical energy. The fuel for such a power plant can be coal, peat, gas, oil shale, and fuel oil.
Thermal power plants are divided into condensation(IES), designed to generate only electrical energy, and combined heat and power plants(CHP), producing, in addition to electrical energy, thermal energy in the form of hot water and steam. Large CPPs of regional significance are called state district power plants (SDPPs).
The simplest circuit diagram A coal-fired IES is shown in the figure. Coal is fed into the fuel bunker 1, and from it into the crushing unit 2, where it turns into dust. Coal dust enters the furnace of a steam generator (steam boiler) 3, which has a system of tubes in which chemically purified water, called feedwater, circulates. In the boiler, the water is heated, evaporated, and the resulting saturated steam is brought to a temperature of 400-650 °C and, under a pressure of 3-24 MPa, enters steam turbine 4 through a steam line. Steam parameters depend on the power of the units.
Thermal condensing power plants have low efficiency (30-40%), since most of the energy is lost with flue gases and condenser cooling water. It is advantageous to build CPPs in close proximity to fuel production sites. In this case, electricity consumers may be located at a considerable distance from the station.
Combined heat and power plant differs from a condensing station by having a special heating turbine installed on it with steam extraction. At a thermal power plant, one part of the steam is completely used in the turbine to generate electricity in the generator 5 and then enters the condenser 6, and the other, having a higher temperature and pressure, is taken from the intermediate stage of the turbine and is used for heat supply. The condensate is supplied by pump 7 through the deaerator 8 and then by the feed pump 9 to the steam generator. The amount of steam taken depends on the thermal energy needs of enterprises.
The efficiency of thermal power plants reaches 60-70%. Such stations are usually built near consumers - industrial enterprises or residential areas. Most often they run on imported fuel.
Thermal stations with gas turbine(GTPP), steam-gas(PHPP) and diesel plants.
Gas or liquid fuel is burned in the combustion chamber of a gas turbine power plant; combustion products with a temperature of 750-900 ºС enter a gas turbine that rotates an electric generator. The efficiency of such thermal power plants is usually 26-28%, power - up to several hundred MW . GTES are usually used to cover peaks electrical load. The efficiency of PGES can reach 42 - 43%.
The most economical are large thermal steam turbine power plants (abbreviated TPP). Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are consumed. In a steam boiler, over 90% of the energy released by the fuel is transferred to steam. In the turbine, the kinetic energy of the steam jets is transferred to the rotor. The turbine shaft is rigidly connected to the generator shaft.
Modern steam turbines for thermal power plants - very advanced, high-speed, highly economical machines with a long service life. Their power in a single-shaft version reaches 1 million 200 thousand kW, and this is not the limit. Such machines are always multi-stage, that is, they usually have several dozen disks with working blades and the same number, in front of each disk, of groups of nozzles through which a stream of steam flows. The pressure and temperature of the steam gradually decrease.
It is known from a physics course that the efficiency of heat engines increases with increasing initial temperature of the working fluid. Therefore, the steam entering the turbine is brought to high parameters: temperature - almost 550 ° C and pressure - up to 25 MPa. The efficiency of thermal power plants reaches 40%. Most of the energy is lost along with the hot exhaust steam.
Hydroelectric station (hydroelectric power station), a complex of structures and equipment through which the energy of water flow is converted into electrical energy. A hydroelectric power station consists of a series circuit hydraulic structures, providing the necessary concentration of water flow and creating pressure, and power equipment that converts the energy of water moving under pressure into mechanical rotational energy, which, in turn, is converted into electrical energy.
The pressure of a hydroelectric power station is created by the concentration of the fall of the river in the area used by the dam, or derivation, or a dam and diversion together. The main power equipment of the hydroelectric power station is located in the hydroelectric power station building: in the turbine room of the power plant - hydraulic units, auxiliary equipment, automatic control and monitoring devices; in the central control post - operator-dispatcher console or auto operator of a hydroelectric power station. Increasing transformer substation It is located both inside the hydroelectric power station building and in separate buildings or in open areas. Switchgears often located in an open area. A hydroelectric power plant building can be divided into sections with one or more units and auxiliary equipment, separated from adjacent parts of the building. An installation site is created at or inside the hydroelectric power station building for the assembly and repair of various equipment and for auxiliary operations for the maintenance of the hydroelectric power station.
According to installed capacity (in MW) distinguish between hydroelectric power stations powerful(over 250), average(up to 25) and small(up to 5). The power of a hydroelectric power station depends on the pressure (the difference between the levels of the upstream and downstream ), water flow used in hydraulic turbines and the efficiency of the hydraulic unit. For a number of reasons (due to, for example, seasonal changes in the water level in reservoirs, fluctuations in the load of the power system, repairs of hydraulic units or hydraulic structures, etc.), the pressure and flow of water continuously change, and, in addition, the flow changes when regulating the power of a hydroelectric power station. There are annual, weekly and daily cycles of hydroelectric power station operation.
Based on the maximum used pressure, hydroelectric power stations are divided into high-pressure(more than 60 m), medium pressure(from 25 to 60 m) And low-pressure(from 3 to 25 m). On lowland rivers pressures rarely exceed 100 m, in mountainous conditions, a dam can create pressures of up to 300 m and more, and with the help of derivation - up to 1500 m. The division of hydroelectric power stations according to the pressure used is of an approximate, conditional nature.
According to the pattern of water resource use and pressure concentration, hydroelectric power stations are usually divided into channel , dam , diversion with pressure and non-pressure diversion, mixed, pumped storage And tidal .
In run-of-river and dam-based hydroelectric power plants, the water pressure is created by a dam that blocks the river and raises the water level in the upper pool. At the same time, some flooding of the river valley is inevitable. Run-of-river and dam-side hydroelectric power stations are built both on lowland high-water rivers and on mountain rivers, in narrow compressed valleys. Run-of-river hydroelectric power stations are characterized by pressures up to 30-40 m.
At higher pressures, it turns out to be inappropriate to transfer hydrostatic water pressure to the hydroelectric power station building. In this case the type is used dam A hydroelectric power station, in which the pressure front is blocked along its entire length by a dam, and the hydroelectric power station building is located behind the dam, is adjacent to the tailwater.
Another type of layout dammed The hydroelectric power station corresponds to mountain conditions with relatively low river flows.
IN derivational Hydroelectric power station concentration of the river fall is created through diversion; water at the beginning of the used section of the river is diverted from the river bed by a conduit with a slope significantly less than the average slope of the river in this section and with straightening the bends and turns of the channel. The end of the diversion is brought to the location of the hydroelectric power station building. Waste water is either returned to the river or supplied to the next diversion hydroelectric power station. Diversion is beneficial when the river slope is high.
A special place among hydroelectric power stations is occupied by pumped storage power plants(PSPP) and tidal power plants(PES). The construction of pumped storage power plants is driven by the growing demand for peak power in large energy systems, which determines the generating capacity required to cover peak loads. The ability of pumped storage power plants to accumulate energy is based on the fact that free electrical energy in the power system for a certain period of time is used by pumped storage power plant units, which, operating in pump mode, pump water from the reservoir into the upper storage pool. During peak load periods, the accumulated energy is returned to the power system (water from the upper basin enters pressure pipeline and rotates hydraulic units operating as a current generator).
PES convert the energy of sea tides into electricity. The electricity of tidal hydroelectric power stations, due to some features associated with the periodic nature of the ebb and flow of tides, can be used in energy systems only in conjunction with the energy of regulating power plants, which make up for the power failures of tidal power stations within days or months.
The most important feature of hydropower resources compared to fuel and energy resources is their continuous renewability. The absence of fuel requirement for hydroelectric power plants determines the low cost of electricity generated by hydroelectric power plants. Therefore, the construction of hydroelectric power stations, despite significant specific capital investments by 1 kW installed capacity and long construction periods were and are given great importance, especially when this is associated with the placement of electricity-intensive industries.
Nuclear power plant (NPP), a power plant in which atomic (nuclear) energy is converted into electrical energy. The energy 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 is then converted into electricity in the same way as in conventional thermal power plants (TPPs). Unlike thermal power plants that run on fossil fuels, nuclear power plants run on nuclear fuel(based on 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 of natural reserves of organic fuel (oil, coal, natural gas and etc.). This opens up broad prospects for meeting rapidly growing fuel demands. In addition, it is necessary to take into account the ever-increasing volume of consumption of coal and oil for technological purposes in the world. 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, there is a tendency in the world towards 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 energy, which already occupies a prominent place in the energy balance of a number of industrial countries peace.
Schematic diagram of a nuclear power plant with a nuclear reactor having water cooling, shown in Fig. 2. Heat released in core reactor coolant, is taken in by water from 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. The water of 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 water coolant and heavy water as a moderator;
4) graffito - gas with gas coolant and graphite moderator.
The choice of the predominantly used type of reactor is determined mainly by the accumulated experience in the carrier reactor, as well as the availability of the necessary industrial equipment, raw material reserves, etc.
The reactor and its servicing systems include: the reactor itself with biological protection , heat exchangers, pumps or gas-blowing units that circulate the coolant, pipelines and fittings for the circulation circuit, devices for reloading nuclear fuel, special ventilation systems, emergency cooling systems, etc.
To protect NPP personnel from radiation exposure The reactor is surrounded by biological protection, the main materials for which are concrete, water, and serpentine sand. The reactor circuit equipment must be completely sealed. A system is provided to monitor places of possible coolant leaks; measures are taken to ensure that leaks and breaks in the circuit do not lead to radioactive emissions and contamination of the nuclear power plant 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 rooms of the nuclear power plant special system ventilation, in which cleaning filters and holding gas tanks are provided to eliminate the possibility of air pollution. The compliance with radiation safety rules by NPP personnel is monitored by the dosimetry control service.
The presence of biological protection, special ventilation and emergency cooling systems and a dosimetric monitoring service makes it possible to completely protect NPP operating personnel from the harmful effects of radioactive radiation.
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 do not pollute the environment at all, do not require connection to a source of raw materials and, accordingly, can be located almost anywhere. The new power units have a capacity of almost equal power average hydroelectric power station, however, the installed capacity utilization factor at nuclear power plants (80%) significantly exceeds this figure for hydroelectric power stations or thermal power plants.
NPPs have practically no significant disadvantages 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 sharply, because the potential possibilities of energy based on the use of direct solar radiation are extremely high.
The simplest solar radiation collector 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. Large-scale use of solar energy entails a gigantic increase in the need for materials, and, consequently, in labor resources for the extraction of raw materials, their enrichment, obtaining materials, manufacturing heliostats, collectors, other equipment, and their transportation.
Electrical energy generated by solar rays is still much more expensive than that obtained traditional ways. Scientists hope that the experiments they will conduct at pilot installations and stations will help 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 hydropower reserves of all the rivers on the planet. Winds blow constantly and everywhere on earth. Climatic conditions allow the development of wind energy over a vast territory.
But today, wind engines supply just one thousandth of the world's energy needs. Therefore, aircraft specialists who know how to select the most appropriate blade profile and study it in a wind tunnel are involved in creating the designs of the wind wheel, the heart of any wind power plant. Through the efforts of scientists and engineers, the most various designs modern wind turbines.
Energy of the Earth.
People have long known about the spontaneous manifestations of gigantic energy hidden in the depths of the globe. The memory of mankind preserves legends about catastrophic volcanic eruptions that killed millions human lives, which have changed the appearance of many places on Earth beyond recognition. The power of the eruption of even a relatively small volcano is colossal; it is many times greater than 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; people do not yet have the ability to curb this rebellious element.
The Earth's energy is suitable not only for heating premises, as is the case in Iceland, but also for generating electricity. Power plants using hot underground springs have been operating for a long time. The first such power plant, still very low-power, was built in 1904 in the small Italian town of Larderello. Gradually, the power of the power plant grew, more and more new units were put into operation, new sources of hot water were used, and today the power of the station has already reached an impressive value of 360 thousand kilowatts.
Electricity transmission.
Transformers.
You 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 hopeless situation? Not at all. You just have to make an additional expense and purchase a transformer.
Transformer- a very simple device that allows you to both increase and decrease voltage. The conversion of alternating current is carried out using transformers. Transformers were first used in 1878 by the Russian scientist P. N. Yablochkov to power the “electric candles” he invented, a new light source at that time. P. N. Yablochkov’s idea was developed by Moscow University employee 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 placed (Fig. 1). One of the windings, called the primary winding, is connected to an alternating voltage source. The second winding, to which the “load” is connected, i.e., instruments and devices that consume electricity, is called secondary.
The operation of a transformer is based on the phenomenon of electromagnetic induction. When alternating current passes through the primary winding, an alternating magnetic flux appears in the iron core, which excites an induced emf in each winding. Moreover, the instantaneous value of the induced emf e V 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 0 sin ω t , or
e = E 0 sin ω t ,
Where E 0 = ω Ф 0 - amplitude of the EMF in one turn.
In the primary winding, which has n 1 turns, total induced emf e 1 equal to p 1 e.
In the secondary winding there is a total emf. e 2 equal to p 2 e, Where n 2- the number of turns of this winding.
It follows that
e 1 e 2 = n 1 n 2 . (1)
Sum voltage u 1 , applied to the primary winding, and 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 - active resistance of the winding, and i 1 - current strength in it. This equation follows directly from the general equation. Usually the active resistance of the winding is small and 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 following relationship 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 And E 2 of these EMFs or, taking into account equalities (2) and (3), the ratio of effective voltage values U 1 and U 2 .
U 1 /U 2 = E 1 / E 2 = n 1 / n 2 = k . (4)
Magnitude k called the transformation ratio. If k>1, then the transformer is step-down, when k <1 - increasing
When the secondary winding circuit is closed, current flows in it. Then the ratio 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.
It follows that
U 1 /U 2 = I 1 / I 2 . (6)
This means that by increasing the voltage several times using a transformer, we reduce the current by the same amount (and vice versa).
Due to the inevitable energy losses due to heat release in the windings and iron core, equations (5) and (6) are satisfied approximately. However, in modern powerful transformers, the total losses do not exceed 2-3%.
In everyday practice we 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 the city network uses another, we also have to deal with car bobbins. The bobbin is a step-up transformer. To create a spark that ignites the working mixture, a high voltage is required, which we obtain from the car battery, after first converting the direct current of the battery into alternating current using a breaker. It is not difficult to understand 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 welding machine's transformer has only one output turn.
You probably noticed that the transformer core is made from thin sheets of steel. This is done so as not to lose energy during voltage conversion. In sheet material, eddy currents will play a smaller 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
Electricity consumers are everywhere. It is produced in relatively few places close to sources of fuel and hydro resources. Therefore, there is a need to transmit electricity over distances sometimes reaching hundreds of kilometers.
But transmitting electricity over long distances is associated with noticeable losses. The fact is that as current flows through power lines, it heats them up. In accordance with the Joule-Lenz law, the energy spent on heating the wires of the line is determined by the formula
where R is the line resistance. With a large line length, energy transmission may become generally 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 the wires. But to reduce R, for example, by 100 times, you need to increase the mass of the wire also by 100 times. It is clear that such a large consumption of expensive non-ferrous metal cannot be allowed, not to mention the difficulties of fastening 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, reducing the current by 10 times reduces the amount of heat released in the conductors by 100 times, i.e., the same effect is achieved as from making the wire a hundred times heavier.
Since current power is proportional to the product of current and voltage, to maintain the transmitted power, it is necessary to increase the voltage in the transmission line. Moreover, the longer the transmission line, the more profitable it is to use a higher voltage. 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 more complex special measures to be taken to insulate the windings and other parts of the generators.
That's why step-up transformers are installed at large power plants. The transformer increases the voltage in the line by the same amount as it decreases the current. The power losses are small.
To directly use electricity in the electric drive motors 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 occurs in several stages. At each stage, the voltage becomes less and less, and the territory covered by the electrical network becomes wider. The diagram of transmission and distribution of electricity is shown in the figure.
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Electric power stations in a number of regions of the country are connected by high-voltage transmission lines, forming a common power grid to which consumers are connected. Such an association is called a power system. The power system ensures uninterrupted supply of energy to consumers regardless of their location.
Electricity use.
The use of electrical power in various fields of science.
The twentieth century became the century when science invades all spheres of social life: economics, politics, culture, education, etc. Naturally, science directly influences the development of energy and the scope of application of electricity. On the one hand, science contributes to expanding the scope of application 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 urgent tasks of science are the development of energy-saving technologies and their implementation in life.
Let's look at these questions using specific examples. About 80% of the growth in GDP (gross domestic product) of developed countries is achieved through technical innovation, the main part of which is related to the use of electricity. Everything new in industry, agriculture and everyday life comes to us thanks to new developments in various branches of science.
Most scientific developments begin with theoretical calculations. But if in the 19th century these calculations were made using pen and paper, then in the age of the STR (scientific and technological revolution) all theoretical calculations, selection and analysis of scientific data, and even linguistic analysis of literary works are done using computers (electronic computers), which operate on electrical energy, which is most convenient for transmitting it over a distance and using it. But if initially computers were used for scientific calculations, now computers have come from science to life.
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 complex automation is directly related to microelectronics, a qualitatively new stage of which began after the invention in 1971 of the microprocessor - a microelectronic logical device built into various devices to control their operation.
Microprocessors have accelerated the growth of robotics. Most of the robots currently in use belong to the so-called first generation, and are used for welding, cutting, pressing, coating, etc. The second generation robots that are replacing them are equipped with devices for recognizing the environment. And third-generation “intellectual” robots will “see,” “feel,” and “hear.” Scientists and engineers name nuclear energy, space exploration, transport, trade, warehousing, medical care, waste processing, and the development of the riches of the ocean floor among the highest priority areas for using robots. The majority of robots operate on electrical energy, but the increase in electricity consumption by robots is offset by a decrease in energy costs in many energy-intensive production processes due to the introduction of more rational methods and new energy-saving technological processes.
But let's get back to science. All new theoretical developments after computer calculations are tested experimentally. 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 imaging scanners, etc. The bulk of these instruments of experimental science are powered by electrical energy.
Science in the field of communications and communications is developing very rapidly. Satellite communications are no longer used only as a means of international communication, but also in everyday life - satellite dishes are not uncommon in our city. New means of communication, such as fiber technology, can significantly reduce energy losses in the process of transmitting signals over long distances.
Science has not bypassed the sphere of management. As scientific and technological progress develops and the production and non-production spheres of human activity expand, management begins to play an increasingly important role in increasing their efficiency. From a kind of art, which until recently was based on experience and intuition, management today has turned into 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 works of ancient Greek philosophers. However, its rebirth actually occurred in 1948, after the publication of the book “Cybernetics” by the American scientist Norbert Wiener.
Before the start 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 birth to a fundamentally different one - 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 automated control systems (automated control systems), information data banks, automated information databases, computer centers, video terminals, copying and phototelegraph machines, national 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 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 ones;
· turning information into one of the most important factors in 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 for 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 80s, more than 1/3 of all energy consumption in the world was carried out in the form of electrical energy. By the beginning of the next century, this share may increase to 1/2. This increase in electricity consumption is primarily associated with an increase in its consumption in industry. The bulk of industrial enterprises operate on electrical energy. High electricity consumption is typical for energy-intensive industries such as metallurgy, aluminum and mechanical engineering.
Electricity in the home.
Electricity is an essential assistant in everyday life. Every day we deal with her, and, probably, we can no longer imagine our life without her. Remember the last time your lights were turned off, that is, there was no electricity coming to your house, remember how you swore that you didn’t have time to do anything and you needed light, you needed a TV, a kettle and a bunch of other electrical appliances. After all, if we were to lose power forever, we would simply return to those ancient times when food was cooked over fires and we lived in cold wigwams.
A whole poem can be dedicated to the importance of electricity in our lives, it is so important in our lives and we are so accustomed to it. Although we no longer notice that it is coming into our homes, when it is turned off, it becomes very uncomfortable.
Appreciate electricity!
Bibliography.
1. Textbook by S.V. Gromov “Physics, 10th grade.” Moscow: Enlightenment.
2. Encyclopedic dictionary of a young physicist. Compound. V.A. Chuyanov, Moscow: Pedagogy.
3. Ellion L., Wilkons U.. Physics. Moscow: Science.
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: Science.
>> Production and use of electrical energy
§ 39 PRODUCTION and USE OF ELECTRIC ENERGY
Nowadays, the level of energy production and consumption is one of the most important indicators of the development of industrial production forces. The leading role here is played by electricity - the most universal and convenient form of energy to use. If energy consumption in the world doubles in about 25 years, then an increase in electricity consumption by 2 times occurs on average in 10 years. This means that more and more energy-consuming processes are being converted to electricity.
Power generation. Electricity is produced at large and small power plants mainly using electromechanical induction generators. There are two main types of power plants: thermal and hydroelectric. These power plants differ in the engines that rotate the generator rotors.
At thermal power plants, the source of energy is fuel: coal, gas, oil, fuel oil, oil shale. Rotors electric generators driven by steam and gas turbines or internal combustion engines. The most economical are large thermal steam turbine power plants (abbreviated as TPP). Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are consumed. In a steam boiler, over 90% of the energy released by the fuel is transferred to steam. In the turbine, the kinetic energy of the steam jets is transferred to the rotor. The turbine shaft is rigidly connected to the generator shaft. Steam turbogenerators are very fast: the rotor speed is several thousand per minute.
From the 10th grade physics course it is known that the efficiency of heat engines increases with increasing temperature of the heater and, accordingly, the initial temperature of the working fluid (steam, gas). Therefore, the steam entering the turbine is brought to high parameters: temperature - almost 550 ° C and pressure - up to 25 MPa. The efficiency of thermal power plants reaches 40%. Most of the energy is lost along with the hot exhaust steam. Energy transformations are shown in the diagram shown in Figure 5.5.
Thermal power plants - the so-called combined heat and power plants (CHPs) - allow a significant part of the energy from waste steam to be used in industrial enterprises and for domestic needs (for heating and hot water supply). As a result, the efficiency of the thermal power plant reaches 60-70%. Currently in Russia, thermal power plants provide about 40% of all electricity and supply hundreds of cities with electricity and heat.
Hydroelectric power plants (HPPs) use the potential energy of water to rotate generator rotors. The rotors of electric generators are driven by hydraulic turbines. The power of such a station depends on the difference in water levels created by the dam (pressure) and on the mass of water passing through the turbine every second (water flow). Energy transformations are shown in the diagram shown in Figure 5.6.
Hydroelectric power plants provide about 20% of all electricity generated in our country.
Play a significant role in the energy sector nuclear power plants(NPP). Currently, nuclear power plants in Russia provide about 10% of electricity.
Electricity use. The main consumer of electricity is industry, which accounts for about 70% of the electricity produced. Transport is also a major consumer. An increasing number of railway lines are being converted to electric traction. Almost all villages and villages receive electricity from power plants for industrial and domestic needs. Everyone knows about the use of electricity for lighting homes and in household electrical appliances.
Most of the electricity used is now converted into mechanical energy. Almost all machinery in industry is driven by electric motors. They are convenient, compact, and allow for automation of production.
About a third of the electricity consumed by industry is used for technological purposes (electric welding, electric heating and melting of metals, electrolysis, etc.).
Modern civilization is unthinkable without the widespread use of electricity. Power supply disruption big city an accident paralyzes his life.
1. Give examples of machines and mechanisms that would not use electric current at all!
2. Have you been near an electric current generator at a distance not exceeding 100 m!
3. What would the residents of a big city lose in the event of an electrical network failure!
Myakishev G. Ya., Physics. 11th grade: educational. for general education institutions: basic and profile. levels / G. Ya. Myakishev, B. V. Bukhovtsev, V. M. Charugin; edited by V. I. Nikolaeva, N. A. Parfentieva. - 17th ed., revised. and additional - M.: Education, 2008. - 399 p.: ill.
Physics and astronomy for grade 11 free download, lesson plans, preparing for school online
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