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Medium voltage networks in different countries. System Operator of the Unified Energy System
Frequency is measured in Hertz, denoted by the letter "F" (the number of occurrence of an event per second). Well, for example, a person's pulse is 60 beats per minute, which means that the frequency with which the heart beats is F=60/60=1 Hz. When playing a vinyl record, it makes 33 revolutions per minute - F=33/60=0.55 Hz. The refresh rate of a CRT monitor screen is 200 Hz, which means that the electron beam "runs through" the screen 200 times per second.
In relation to energy, frequency is understood as the frequency of alternating electric current in the power system. Or else they say "industrial frequency". We and in Europe have a frequency of 50 Hz. In the USA and Japan 60 Hz. What does it mean? This means that 50 times per second, the electric current flows with increasing-decreasing (according to a sinusoid) in one direction, 50 times in the other. A few words why the industrial frequency is exactly 50 or 60 Hz. It's just that the frequency of the current appears due to the rotation of the generator rotor. If you increase the rotor speed (and, accordingly, the frequency in the power system), you need to make the design of the generator more durable. And it is impossible to increase the strength to infinity, any structural materials have a limit. In short, 50-60 Hz is a balance of many technical limitations.
Paul decides to electrify the Midi network in the German-Swiss system, that is, in high-voltage monophase, until the Pyrenean circuit benefits from some kind of hydroelectric power plant. Everything must be undertaken, which will eventually lead to the creation of high-fall dams in the high valleys of the Pyrenees and the general electrification of the regions of Aquitaine and Languedocien. First World War and the emergence of a new main actor - the state. Under these conditions, the state was asked to intervene in general electrification programs, for example, in the operation of railways.
When there are no problems with the frequency, there is no mention of this value in journalistic materials. But this may not always be the case. What can the frequency deviation from the nominal lead to (we have 50 Hz)? To a serious accident! When the frequency is higher than the nominal 50 Hz, centrifugal forces of greater magnitude act on the rotating rotor of the generator and turbine than are inherent in their design. This can lead to their destruction. Of course there is automation. If F reaches 55 Hz, the unit will automatically disconnect from the mains to prevent damage. If the frequency is below 50 Hz, there is a decrease in the performance of all electric motors (reduction in their rotational speed) connected to the power system - both those that provide the operation of escalators in the supermarket, and those that rotate the conveyor belt in the factory, and those that provide the production process electricity at power plants. The last one is the most dangerous. Frequency decreases, power generation decreases, which leads to an even greater decrease in frequency, as a result - power plants can simply “go to zero” (if the frequency drops to 45 Hz), this is a complete repayment, as they say blackout. Of course, there is automation here too. In order to prevent a deep decrease in frequency, some consumers are automatically turned off, including “household” ones. The above is of course extreme cases of accidents. But the frequency can also deviate by smaller values. This is also bad. And the power system provides automation to avoid this. Here I painted a little how it works, if you are interested, read it.
This is due to the operation of dams and the standardization of the main communication or energy networks, but above all, the conflict has led to industrial mobilization, which is necessary for the needs national defense. coal punishes the French railways, which still get the bulk of their energy resources from them. Thus, the electrification of the rail is connected with the electrification of the general electrical distribution network protected by public works.
It includes the former Minister of Public Works, Louis Louhur, and its reporter is Academician Prof. Maudute of the Faculty of Nancy. The General Staff has deprived its representatives, who express military unwillingness towards women, the possible electrification of the lines of the East and North of France. The first conclusions of the Committee reflect moderate enthusiasm, as there are fragmentary experiments - one thousand electric locomotives in service in the world, compared to three hundred thousand pairs - and, above all, many technical provisions that strengthen some of its members in the conviction of the superiority of steam for great traction. .
A little more theory (be patient, since we have reached here). The frequency in the system, the value of exactly 50 Hz can be only in one case - if at each moment of time exactly as much active power is generated as it is consumed. If this balance is violated, the frequency "leads" to one side or the other, and this leads to an accident. Imagine any other enterprise (furniture factory, bakery, car factory) and the same task - every fraction of a second to produce exactly as much product as consumers need. You can see how complex the production of power engineers is. What is interesting here - if the frequency is higher than 50 Hz, then the generators produce more power than the power of all consumers, well, this is easily treated - the output at power plants is reduced, and that's all. If the frequency is below 50 Hz, the power consumption is greater than the generated power. And if the frequency is always below 50 Hz, then there is a power shortage in the power system. Power plants were not built on time - this is a big problem.
Natalis Mazen, who is then engaged in an extensive plan for the electrification of the suburbs of the western part of Paris. In a conference presented before the French Electrician Company said that electricity has not yet proven its worth in railway traffic. In the United States, this has been mainly a source of technical and economic difficulties; for example, it cannot be better than steam locomotives. Parallel to this administrative investigation, a debate began between locomotive builders and operators.
The first organized a mission of French industrialists in Switzerland, where Georges Darrius was an engineer at the Electromechanical Company, to reconsider alternatives. The operators responded by rushing out of "Central Building and Training", an emanation of the major networks, and they went to visit the British North East, where there was a 1.5 kV electrified line from Dick Kerr. The single-phase alternator is rejected under the pretext of the disturbances it will generate in the telephone network along the railroad tracks.
Today, Russia provides us with a high-quality frequency of 50 Hz. It is there that high-speed frequency regulators with an impact on Russian stations are located. When you turn on the iron, somewhere far away in Russia, the generator is loaded with an additional 1.5 kW, and vice versa (this is a bit simplified, but for the most part it is). Neither in the UES of Kazakhstan, nor in the energy systems of Central Asia, today, there are no systems that allow you to keep the frequency "in tune" at the level of 50 Hz. If we separate from Russia (electrically), our frequency will fluctuate, which is very bad.
Dirigisme and technological chauvinism. Obviously, this decision is tantamount to condemning the first implementations of Midi in AC. Baene - Eshenburg will ask him if he can think that he can produce direct motors operating in single-phase fifty periods, but if direct current is suitable for power commutator motors, it creates large requirements for fixed equipment. motors of machines designed for high-intensity operation, the number of substations must be multiplied, and a copper catheter designed to prevent line losses must be installed.
And one more thing - the frequency is a global factor. It is the same everywhere in the power system. And in Kazakhstan and throughout Russia (the part that is part of the EEC), it is the same at the same time. If in some part the frequency has changed, then this part is electrically disconnected (due to an accident or for other reasons) and is isolated from the main power system.
In short, if it is not disputed that its equipment cost is much higher than that of the alternative, Parodi believes that continuous will not prevent output. railway from those uses where it was limited to this point and mountain lines. Finally, it should be added that after the rejection of the alternative monophase comes the rejection by French engineers of the skills of electricians on the other side of the Rhine. At the end of the First World War, the risk was caused by the compatibility of electrification between the two countries, which would allow revenge on the vanquished with the reacquisition of their locomotives. winning technique, that is direct current used in Anglo-Saxon countries.
Just don’t tell me: “Dad, who were you talking to right now?”. Just kidding, of course :) Let's move on.
EEC - Unified Electric Power System. This is a set of power plants, substations and transmission lines connected by a single common technological mode of operation. In short, everything that works "in parallel" and is interconnected (everything that is interconnected by power lines) constitutes the EEC. And although there is the UES of Kazakhstan and the UES of Russia, in fact it is more of a political division, “electrically” it is all one energy system, which used to be called the UES of the USSR. But, for example, the power system of Australia is not included in our UES, since it is not connected with us by power lines.
Expansion of the "Parodi" system. However, while the rectifier locomotives caused significant disruption, harmonics were sent to the grid, direct drive machine switching was never satisfactory, and it assured the reliability of a direct drive, the most logical way to use AC, he said. However, this type of engine has certain disadvantages besides its foreign origin, such as subtle shifting, which raises the fear of costly maintenance.
Another solution seems to be to use rectifiers. Immediately after the war, European unification began with the normalization of Franco-German relations. French Economy Minister André Philippe presented to the Consultative Assembly of the Council of Europe a project to coordinate the main sectors of industry and transport in the Ruhr-Sarre-Lorraine region. Thus, the Annecy Congress brings together builders, operators and representatives of public authorities from the point of view of European construction. German State Secretary for Transport Dr. Speech is about the unification of Europe by removing electrical boundaries between rail networks.
CL - cable line power transmission - a cable is laid underground, of course with powerful insulation. The cost of cable lines is much more expensive than overhead lines, therefore in the USSR, it was customary to lay cable lines only inside settlements so as not to disfigure the appearance. Such savagery, as in other countries, when all the intestines are unwound through the streets, you will not find here.
In his opening speech, Louis Armand recalled the economic advantages of railway electrification in industrial currents and proposed nothing less than a merging of European railways around new railway electrification technology: "all means of transport will have to contribute to the constitution of a united Europe".
In this regard, it is, however, about the elimination of rail transport, which in itself can fulfill the obligations of a great public service, he said. However, the project to combine the electrification of Western European railways into single-phase 50 Hz is facing serious restraint. Indeed, in both Switzerland and Germany, farmers show little interest in moving away from their special frequency electrical systems. Thus, despite some final discussions, especially regarding the electrification of the Ruhr lines, the Germans will not return to their position.
The very first cable line was designed not to transmit electricity, but to transmit signals. In 1843, the US Congress announced a tender for the construction of an experimental telegraph line, which was won by Morse (known to us by the "Morse code"), so they decided to lay the line underground. However, due to the fact that Morse's companion decided to save money on insulation for wires, instead of a line, there was one continuous short circuit (such situations still happen today, when merchants begin to control techies). And more than enough money has already been spent. Engineer Cornell, participating in the project, suggested such a way out of the situation - to place poles along the route, and hang bare telegraph wires directly on these poles, using the necks of glass bottles as insulators. This is how an overhead telegraph line appeared, an electric overhead line is practically its copy, and even today the design has not fundamentally changed.
In the near future, electrification along the industrial current, therefore, concerns only the artery of Valenciennes Thionville, then shortly after the Luxembourg railway. The power supply of the northeast cross section is provided by coal-fired power plants, as will be known, but later.
However, the success of electrification in the northeast does not lead to a Franco-German debate. Even at this level, the situation gets worse, as 50 Hz requires special catheters and transformers, so simplified solutions for spartan electrification. Also the first cousins pretend to see only "deceit" in the arguments of their Gallic neighbors! Universal technologies and national industries.
VL - overhead power line. Serves for the transmission of electricity through wires that are suspended from the support by means of insulators. The higher the operating voltage of the overhead line, the higher the supports and the greater the number of insulators in the garland. There is only one insulator on the 6.10 kV overhead line, 2 insulators on the 35 kV overhead line, 6 insulators on the 110 kV overhead line, 12 insulators on the 220 kV overhead line, 24 insulators on the 500 kV overhead line, so in appearance it is not difficult to determine the operating voltage of the overhead line.
This story also shows that innovation comes from a tradition of technical fields found in other areas such as nuclear energy, aerospace or telecommunications. From time to time the question arises: who is the greatest hacker of all time? Others still claim that the biggest is Richard Stallman of the Massachusetts Institute of Technology.
Let me therefore introduce you, he and his great black. The story begins some time ago: a scientist moves to the city and opens a laboratory on Hill Street, on the southern outskirts. So Tesla moved to Colorado Springs and started working. But people didn't know it was just a joke! The laboratory man was simply fine-tuning his instrument, preparing to make this experiment one of the greatest and most impressive of all time.
hydroelectric power station - a hydroelectric station (it can also stand for a hydraulic power station, try not to use the colloquial "hydro station" - in my opinion, it sounds vulgar). A hydroelectric power station is a power plant where electricity is obtained by converting the energy of water (the flow of water turns a turbine). There are not many large hydroelectric power stations in Kazakhstan. If compared in terms of capacity, then all HPPs will make up no more than 10% of all generating capacities in the UES. This is bad. In order for the energy system to be self-sufficient, it is necessary to have at least 20-30% of hydroelectric power stations in the system, but what can you do - water resources are not enough. The advantage of a hydroelectric power station is its high maneuverability. Such stations can quickly pick up the load and also quickly dump it (this is necessary for accurate frequency control at the level of 50 Hz). What hydroelectric power plants do we have?
It was called Nikola Tesla, an immigrant from what is now Yugoslavia. In Belgrade he also built a museum in his honor and his works. And those who, like him, fail are slowly disappearing from the public eye. Moreover, this is what happens every day in the IT industry! Edison, who was not Tesla's friend but a great businessman, is remembered as the inventor of the incandescent lamp and his General Electric.
To give you an idea of his talent, let me list some other discoveries. He is the father of the AC motor and transformers. He invented three-phase electricity and spread alternating current as well as the system. Dosing is used all over the world. Now he is also recognized as the inventor of the modern radio: the Supreme Court accepted the patent in Marconi and gave it to him.
The movement of electrons in a wire first in one direction and then in the other is called one alternating current oscillation. The first oscillation is followed by the second, then the third, and so on. When the current fluctuates in the wire, a corresponding oscillation of the magnetic field occurs around it.
The time of one oscillation is called a period and is denoted by the letter T. The period is expressed in seconds or in units that make up fractions of a second. These include: a thousandth of a second - a millisecond (ms), equal to 10 -3 s, a millionth of a second - a microsecond (μs), equal to 10 -6 s, and a billionth of a second - a nanosecond (ns), equal to 10 -9 s.
In a nutshell, Tesla invented most of the equipment that drives miles and miles into your homes every day, but also invented many of the tools that the current one consumes! His inventions made George Westinghouse a wealthy man. Did you know that the unit of magnetic flux is "tesla"? Understand that these are a few differences: we are not talking about a completely unfamiliar, but about an inevitable electronic engineer!
As a young man, Tesla made an amazing amount of discoveries, but he was really resonant, especially electromagnetic. Thus was born his sensational discovery: he notices that really strange things happen when electrical circuit undergoes resonance. Tesla, at the same resonant frequency as the primary and secondary, obtained in an electric field, which is evident in a mechanical field, that is, a huge amplification of the output current, which leads to high-frequency frequencies of 000 Hz and extraordinary voltages that can reach values of a million volts Voltage exits from the top of the coil, forming what is known as the "crown" or "bow" effect.
An important quantity that characterizes is the frequency. It represents the number of oscillations or the number of periods per second and is denoted by the letter f or F. The unit of frequency is the hertz, named after the German scientist G. Hertz and abbreviated as Hz (or Hz). If one complete oscillation occurs in one second, then the frequency is one hertz. When ten vibrations are made within a second, the frequency is 10 Hz. Frequency and period are reciprocals:
Relatively low volumes, on the order of 000 volts, produce sparks of six inches, the highest, 000 volts, sparks several feet long. Tesla was able to attract sparks to his fingers without being injured, and this is because the high frequency does not cross the conductors, but passes through the outer surface. Since then, Tesla began to think about resonant applications on a larger scale. He was the pioneer of the power distribution system we use today, and it's not just stuff! When you think of Tesla, think big!
Answer: Earth is a good electrical conductor! Let me explain how it works and you will understand too. Many people think that the earth is not a good conductor. Indeed, the earth is capable of absorbing large amounts of electricity, and therefore all appliances that transmit electrical current are discharged to earth: the third terminal, the center one of the AC sockets, has a wiring harness directly to earth.
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At a frequency of 10 Hz, the period is 0.1 s. And if the period is 0.01 s, then the frequency is 100 Hz
AT electrical network AC frequency is 50 Hz. The current flows fifty times per second in one direction and fifty times in the opposite direction. One hundred times per second, it reaches the amplitude value and becomes equal to zero a hundred times, i.e., changes its direction a hundred times when passing through the zero value. The lamps connected to the network dim a hundred times per second and flash brighter the same number of times, but the eye does not notice this due to visual inertia, i.e., the ability to store the impressions received for about 0.1 s.
In calculations with alternating currents, the angular frequency ω is also used, it is equal to 2πf or 6.28f. It should be expressed not in hertz, but in radians per second (a radian is an angle 2π times smaller than 360 °).
Alternating currents are usually divided by frequency. Currents with a frequency of less than 10,000 Hz are called low frequency currents (LF currents). These currents have a frequency corresponding to the frequency of various sounds of the human voice or musical instruments, and therefore they are otherwise called audio frequency currents (with the exception of currents below 20 Hz, which do not correspond to audio frequencies). In radio engineering, low-frequency currents are of great use, especially in radiotelephone transmission.
However, the main role in radio communication is played by alternating currents with a frequency of more than 10,000 Hz, called high-frequency currents, or radio frequencies (HF currents). To measure the frequency of these currents, units are used: kilohertz (kHz), equal to a thousand hertz, megahertz (MHz), equal to a million hertz, and gigahertz (GHz), equal to a billion hertz. Otherwise, kilohertz, megahertz and gigahertz denote kHz, MHz, GHz. Currents with a frequency of hundreds of megahertz and above are called superhigh or ultrahigh frequency currents (UHF and UHF).
Radio stations operate using high-frequency alternating currents with a frequency of hundreds of kilohertz and higher. In modern radio engineering, for special purposes, currents with a frequency of billions of hertz are used, and there are devices that make it possible to accurately measure such ultrahigh frequencies.
