Generation of electrical energy. Transformers

History of the world electric power industry

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

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

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

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

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

Theoretical basis

Ether and the theory of relativity

The historical facts that have reached us indicate that the majority of scientists known to science were engaged in the study of ether. The term “ethereal” usually meant a not fully understood field formation such as the Absolute Void, filling all the free space between atoms and molecules. The situation changed somewhat only after A. Einstein published his theoretical research on the special theory of relativity with conclusions about the curvature of space and the relativity of time.

After this, all ideas about the existence of the ether were called into question, since in the light of the latest data it was impossible to imagine a curved space in the absence of a material carrier. In addition, the “Special Theory of Relativity” could in no way explain the effects of transformation of mass and other quantities when the speed of movement of material objects in the ether changes.

Ignoring the conclusions of A. Einstein

Despite long-term disputes between theorists and representatives of the exact sciences, the thoroughly forgotten “ethereal” aspect began to attract the attention of researchers again over time. Only with its help could it be somehow possible to explain the presence of so-called “dark matter”, as well as the notorious torsion fields of Akimov and a number of other carriers of hidden energy

Since a practical justification for all these effects was never given, most amateurs were content with their real manifestations in the form of homemade generators of electromagnetic radiation. The first developments were implemented at one time by the great Serbian scientist Nikola Tesla (the general view of the object of his invention is shown in the photo below).

Tesla and his coils

Thanks to the discoveries of this legendary man, it was possible to achieve certain successes in the creation of free energy generators and the preparation of an appropriate theoretical basis for their functioning.

Explanation of the effects of N. Tesla

There are many explanations of Tesla's e/m effects, which define them as a type of field structure formed when a high-frequency electrical signal passes through a conductor.

When current oscillates in a circuit, for example, energy from the ether is first pumped into it and then pushed out, which causes the propagation of e/m waves. At the same time, it was taken into account that the magnitude of the field created around a conductor carrying current is proportional to the square of its amplitude. From a theoretical point of view, this phenomenon was explained by the fact that the wave-like oscillatory motion of charged particles causes the formation of surface current vortices that induce high-frequency fields.

Additional Information. In fact, their origin is associated with the kinetic nature of the processes occurring (more precisely, with the high frequency of generated oscillations).

Based on the proposed explanations, the theoretical justification can be presented in the form of the following analogy:

• Movement in the ether is in some ways very similar to the movement of liquid in a pipe with outlets not filled with water, due to the rapid movement of which a certain vacuum is created in it;
• The reduced pressure leads to the effect of drawing in foreign particles of liquid from the adjacent outlets (this corresponds to the injection of e/m field energy from the ether);
• With a sharp deceleration of the flow of particles, they will splash out and restore pressure inside the pipe;
• The latter effect corresponds to the spark breakdown of electric current through the spark gap, leading to the formation of a powerful burst of energy with impact properties.

It is the reason for the formation of high-intensity e/m fields with unique characteristics that extend over long distances.

This interpretation can be considered a fairly convincing explanation of the effect that has been observed for many years in Tesla generators and similar devices that provide practically free energy.

History of Russian electric power industry

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

Transmission of electricity over a distance

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

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

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

Territorial structure of electricity production

Technical aspects of connection

Amendments to the Energy Law introduced in the State Duma simplify the connection of microgeneration facilities to the power grid for the purpose of selling excess electricity. For them, approval from Rostekhnadzor is canceled, but this does not mean that you will not have to coordinate the sale of energy with your sales organization. Specific technical details of connection are not specified in the bill; many by-laws will have to be created for them.

Technically, there is nothing complicated about transferring electricity from the client to the network. As a rule, imported models of solar power plants have this function, and for now Russian users have to turn it off. An inverter is used, the frequency of which is adjusted to the frequency of the mains voltage to ensure complete synchronism

It is important that the inverter produces a pure sine wave, and not an approximation of it. To avoid phase imbalance, a three-phase connection to the network is recommended

It is possible that the presence of a three-phase connection in the house (and for modern individual buildings this is quite common) will be indicated by sales companies as a prerequisite for allowing the client to sell excess electricity.

You will also have to change your electricity meters. Most existing models of electric meters equally take into account both the energy received from the network and the energy supplied to it. By the way, this leads to curious cases when, in order to provide backup power, the owner of a solar power plant connects it to the network, forgetting to turn off the function of transferring excess electricity to the network. As a result, the counter begins to spin at double speed.

At first, due to the small number of microgeneration facilities and the low power they supply to the network, there will be no need to make any changes to the power grid management systems. In the longer term (second half of the 2020s), the rapid development of microgeneration will be accompanied by the total digitalization of electrical networks, which completely solves the problem of managing distributed generation.

Basic technological processes in the electric power industry

Determination of power quality by analyzers

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

Three types of electricity generation

Electric power industries

Electricity consumption of household appliances

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

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

Nuclear power

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

Nuclear reactor operation diagram

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

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

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

View of the nuclear power plant

Thermal energy

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

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

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

Hydropower

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

hydroelectric power station

alternative energy

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

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

Generation of electrical energy. Transformers

In this topic we will talk about methods of generating electrical energy. We will also study the structure of a simple transformer.

Electromagnetic induction

– this phenomenon lies in the fact that with any change in the magnetic flux penetrating the circuit of a closed conductor, an electric current arises in this conductor, existing throughout the entire process of changing the magnetic flux.
And the current obtained in this way is called induced current
.

Variable

is called
a current
that changes periodically with time.

In order for a sinusoidal alternating current

, the source in this circuit must create an alternating electric field that changes sinusoidally.
In practice, sinusoidal EMF is created by alternating current generators
operating in power plants.

Generators

- These are electrical machines that
convert mechanical energy into electrical energy
.

Generators include voltaic cells, electrostatic machines, thermopiles, solar panels, etc.

Currently, the possibilities of creating fundamentally new types of generators are also being explored.

. For example, fuel cells are being developed and are already partially used, in which the energy released as a result of the reaction of hydrogen with oxygen is directly converted into electricity.

The scope of application of different generators is different and is determined by their characteristics. For example, electrostatic machines create a high potential difference, but they are not capable of creating any significant current in the circuit. Galvanic elements, on the contrary, can produce a large current, but their duration is short.

In modern energy, induction alternating current generators are used, which use the phenomenon of electromagnetic induction. Such generators make it possible to obtain large currents at a sufficiently high voltage.

In the previous topic, the simplest model of such a generator was considered - a frame with current rotating in a uniform magnetic field around its axis.

induction generators available today

. But they all consist of the same basic parts.

Previously, we considered an example of obtaining an induced current in a flat circuit when it rotates in a magnetic field. An electromechanical alternating current generator operates on this principle. The stationary part of the generator, similar to a magnet, is called the stator, and the rotating part, i.e. the frame, is called the rotor.

Powerful industrial generators use an electromagnet instead of a permanent magnet.

The gap between the stator and rotor cores is made as small as possible to increase the flux of the magnetic induction vector.

In the generator model we considered earlier, a wire frame rotates, playing the role of a rotor.

Of course, one could do the opposite, i.e. rotate the magnet and leave the frame motionless. In large industrial generators, it is the electromagnet that is driven into rotation.

.

Industrial generator stator

It is a cylindrical steel frame (
the bed
is the main load-bearing part of the machine on which various working units, mechanisms, etc. are mounted).
In its inner part, grooves are cut into which a thick copper wire
.
It is in them that an alternating electric current is induced when the magnetic flux penetrating them changes. The magnetic field is created by the rotor
.
It is an electromagnet
: a winding is put on a steel core of complex shape, through which a constant electric current flows. The current strength in the windings of the electromagnet that creates the magnetic field is significantly less than the current supplied by the generator to the external circuit. Therefore, it is more convenient to remove the generated current from stationary windings; and through sliding contacts supply a relatively weak current to a rotating electromagnet. Current is supplied to this winding through brushes and rings from an external DC source called the exciter.

The figure shows the complete circuit of the alternator. When the rotor rotates by any external mechanical force, the magnetic field it creates also rotates. In this case, the magnetic flux penetrating the turns of the stator winding periodically changes, as a result of which an alternating current is induced in them.

In thermal power plants, the generator rotor is rotated by a steam turbine; in hydroelectric power plants, by a water turbine.

Please note that the rotor of a hydrogenerator has not one, but several pairs of magnetic poles. The more pairs of poles, the higher the frequency of the alternating electric current produced by the generator at a given rotor speed

. Since the rotation speed of water turbines is usually low, multi-pole rotors are used to create a current of standard frequency.

Thus, electrical energy is produced in power plants

.
But it must somehow be transmitted to consumers, who are often located very far from the station. power lines are built between the station and the consumer

However, when transmitting electricity, losses associated with heating of the wires are inevitable. The farther the current consumer is from the power plant, the more energy is spent on heating the wires and the less reaches the consumer.

Reducing electricity losses during its transmission from power plants to consumers is an important national economic task. From the Joule-Lenz law

It follows that losses can be reduced either by reducing the resistance of the wires or by reducing the current in them.
The resistance of the wires will be lower, the larger their cross-sectional area and the lower the resistivity of the metal from which they are made.
Wires are made of copper or aluminum, since among relatively inexpensive metals they have the lowest resistivity.
However, increasing the thickness of the wires is not economically profitable
, because this leads to excessive consumption of expensive non-ferrous metal, as well as difficulties in securing wires to poles. Therefore, this method of reducing losses is practically impossible.

Therefore, a significant reduction in losses can only be achieved by reducing the current. But given the power, a decrease in current is possible only with an increase in voltage. Without such conversion of current and voltage, transmitting electricity over long distances becomes unprofitable due to significant losses.

Thus, electricity from the Volzhskaya HPP is transmitted to Moscow at a voltage of 500 kV, and from the Sayano-Shushenskaya HPP - at a voltage of 750 kV. Although at the power plants themselves, generators produce electrical energy at voltages not exceeding 20 kV.

The solution to this most important technical problem became possible only after the invention of the transformer

—
a device used to convert AC power and voltage at a constant frequency
.

The first transformer was invented in 1876 by the Russian scientist Pavel Nikolaevich Yablochkov to power the electric candles he invented - a new light source at that time. And the first technical transformer was first created by Ivan Filippovich Usagin in 1882.

The operation of a transformer is based on the phenomenon of electromagnetic induction.

The simplest transformer consists of two coils isolated from each other (they are also called windings), wound on a common closed core. The converted alternating current is passed through one of the windings (primary), and the secondary winding is connected to the consumer.

Alternating current in the primary winding creates an alternating magnetic flux in the core, which excites an inductive emf in the turns of each winding. A transformer steel core concentrates the magnetic field so that the magnetic flux exists almost exclusively inside the core and is the same in all its sections.

The instantaneous value of the induced emf in all turns of the primary or secondary winding is the same

. According to Faraday's law, it will be determined by the formula

e

= –F'

where Ф' is the derivative of the magnetic induction flux with respect to time.

If the primary winding has N

1 turns, and the secondary
N
2 turns, then
e
1 and
e
2 are induced in the windings (without taking into account losses due to magnetic flux dissipation), respectively, and their ratio will be equal

Those. The induction emf (or self-induction) arising in the coils is proportional to the number of turns in them

.

Typically, the active resistance of the transformer windings is small and can be neglected. In this case, the voltage modulus at the terminals of the primary winding is approximately equal to the modulus of the total induced emf.

When the secondary winding of the transformer is open, no current flows in it, therefore the total induced emf is equal to the voltage at the terminals of the secondary winding.

The change in instantaneous EMF values ​​occurs in such a way that they simultaneously reach a maximum and simultaneously pass through zero, i.e. change in phase. Therefore, their ratios can be replaced by the ratio of the effective values ​​of these emfs or the ratio of the effective voltage values.

The ratio of the number of turns in the primary winding to the number of turns in the secondary is called the transformation ratio
k
.

Depending on the value of the transformation ratio, a step-up and step-down transformer

.

It is usually determined when the transformer is no-load, i.e. with the secondary winding circuit open.

If the transformation ratio is less than one, then the transformer is called a step-up transformer, and if it is more than one, then it is called a step-down transformer.

When any load is connected to the secondary circuit (this is the operating stroke of the transformer), the load current

(it is variable and of the same frequency). This current creates a magnetic flux in the core, directed according to Lenz's rule towards the flux of the primary winding. As a result, the total flux of magnetic induction in the primary coil decreases, the EMF also decreases, and, consequently, the current strength will increase. This increase in current in the primary circuit leads to an increase in magnetic flux, induced emf and current in the secondary circuit. But, as we know, an increase in the current in the secondary circuit is accompanied by an increase in the self-induction current and, consequently, a decrease in the magnetic flux that has just increased.

Ultimately, with a constant load, a certain magnetic flux, induced emf in the secondary circuit and current in the primary circuit are established. It turns out that the transformer itself automatically regulates energy consumption depending on the load in the secondary circuit.

During the operating stroke of the transformer, there is a continuous transfer of energy from the primary circuit to the secondary circuit.

The power consumed in the primary circuit will be determined by the formula

and allocated at the load

The efficiency of the transformer will be determined by the ratio of the power released at the load to the power consumed in the primary circuit.

However, not all the energy generated by the generator is transferred to the consumer. During operation of a transformer, there are losses due to heating of the transformer windings, to the dissipation of the magnetic flux into space, to Foucault eddy currents in the core and its magnetization reversal.

To reduce these losses, the following measures are taken:

1) the low voltage winding is made of a larger cross-section, since a greater current passes through it;

2) the core is made closed, which reduces magnetic flux dissipation;

3) the core is made of insulated plates to reduce Foucault currents.

Thanks to these measures, the efficiency of modern transformers reaches 95-99%

, and
the phase shift
between current and voltage fluctuations
is close to zero
.

If sometimes losses in a transformer can be neglected, i.e. Considering its efficiency equal to 100%, then the power consumed in the primary circuit will be equal to the power allocated to the load. Then the ratio of the current in the primary winding to the current in the secondary winding will be inversely proportional to the corresponding voltages

. This means that by increasing the voltage with the help of a transformer, we will decrease the current strength by the same amount and vice versa.

Currently, transformers are widely used both in technology and in everyday life. For example, to transmit electricity over long distances, both step-up and step-down transformers are used (by the way, we will talk about this in more detail in one of the following lessons). When recharging a cell phone, the transformer in the charger lowers the voltage received from the lighting network up to 5.5V suitable for telephone. The TV has several transformers (both step-down and step-up), since voltage from 1.5 V to 25 kV and so on is required to power its various components.

Main conclusions:

– Alternator

- a device that converts mechanical energy into electrical energy.

– In modern energy, induction generators

, whose operation is based on
the phenomenon of electromagnetic induction
, and allowing one to obtain large currents at a sufficiently high voltage.

the rotor remains unchanged in each of them

- the moving part of the generator, and
the stator
- the stationary part of the generator.

– Transformer

– a device used to convert the power and voltage of alternating current at a constant frequency.

– The transformer is characterized by its transformation ratio

, i.e. the ratio of the number of turns in the primary winding to the number of turns in the secondary winding.

– Depending on the value of this coefficient, there are increasing

and
step-down
transformers.

Types of activities in the electric power industry

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

Operational dispatch control

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

Energosbyt

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

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

Video

Coffee capsule Nescafe Dolce Gusto Cappuccino, 3 packs of 16 capsules

1305 ₽ More details

Coffee capsules Nescafe Dolce Gusto Cappuccino, 8 servings (16 capsules)

435 ₽ More details

CAM modules