What is the tension in America. System Operator of the Unified Energy System
The movement of electrons in a wire first in one direction and then in the other is called one oscillation. alternating current. 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.
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:
And
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
In an AC electrical network, the 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 communications 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.
Household appliances from Korea or any other foreign-made appliances are often designed to operate from an electrical network with an alternating current frequency of 60 Hz. Naturally, the owners of such devices have a reasonable question - can they be used in Russia or other countries with a power supply frequency of 50 Hz? The answer is as simple as the multiplication table: you can! But given that the equipment is designed to be powered by a network with a voltage of 220-230 volts. For example, if the nameplate of a Korean juicer has an operating frequency of 60 Hz and a voltage of 220-230V, then the device will work properly.
Where did they even come from?
The world began to electrify in the late 19th and early 20th centuries. In America, Edison and Westinghouse stood at its origins, Europe was “accustomed” to the electric power industry mainly by the engineers of the German company Siemens. Standard frequencies of 50 and 60 Hz were chosen, in general, relatively randomly from the range of 40...60 Hz. Here the range boundaries were not chosen by chance: at a frequency below 40 Hertz they could not work arc lamps, which at that time were the main electrical source artificial lighting, and at a frequency above 60 Hz - did not work asynchronous electric motors designs of Nikola Tesla, the most common in that period ...
In Europe, the 50 Hz standard was chosen (" golden mean”!”), the Americans adopted the 60 Hz standard - arc lamps worked more stable at this frequency. More than a century has passed, arc lamps have become a rarity, but the standards have remained - and this difference of 10 Hz has practically no effect on the performance of electrical equipment. Much more important is the voltage in the electrical network - in many countries it is about half as much as in Russia! And the frequency... in Japan, for example, a third of the prefectures have a standard of 60Hz, and the remaining two-thirds have a standard of 50Hz.
Can? Can!
We can safely say that the performance of household appliances does not depend on the frequency of the power supply. From the point of view of physics in general and electrical engineering in particular, this is quite obvious: at the shaft of a 60 Hz AC electric motor connected to a 50 Hz network, the rotational speed will decrease by only a few percent; slightly reduce the power of the electric motor itself. In other words, it will work in a gentle mode - in the same, for example, cold-pressed screw juicers, this is only for the better.
In devices with motors direct current the frequency of the power supply does not play any role at all - the rectifier diodes installed in the power supply can handle voltage of any shape and "hertz". The difference in the magnitude of the rectified voltages arising due to a change in the frequency of the supply network will be simply scanty; in addition, the rectified voltage is usually stabilized by the electronic "stuffing" of the device.
All of the above is absolutely true for household appliances that have a built-in or external switching power supply. The situation is even simpler if the power supply includes a conventional step-down transformer - its output characteristics change slightly from changes in the voltage frequency in the primary winding. The performance of another type of device - heating - does not at all depend on the frequency of the supply network, for such devices the magnitude of the mains voltage is much more important ...
Can! Just ... carefully!
Appliances designed to be powered by a 60 Hz mains supply can be safely connected to a 50 Hz mains supply. This, by the way, is confirmed by one not too well-known fact: if you open some rather old device with an electric motor - a vacuum cleaner, a hair dryer, a mixer, a cold-pressed juicer - and carefully read the inscriptions on the nameplate of the engine, you can see: "mains frequency ... 50-60 Hz"! The frequency of 60 Hz is used in technology from Korea, USA, Japan and some other countries. Therefore, if you ordered, for example, a juicer from Korea, now you know that even though its operating frequency differs from our networks, you can connect the device!
In fairness, it should be noted that there is still a type of electrical appliances that it is better not to include in the domestic electrical network - this is electrical equipment that uses a single-phase asynchronous motor. And the point here is not even that for such electric motors, the rotation speed does not depend on the frequency of the supply network, but on the load applied to the shaft - the fact is that, due to the principle of their operation, asynchronous electric motors are very sensitive to the frequency of the network at start-up. Designed for 60 Hz, the "asynchronous" at 50 Hz simply will not start ... For example, the same juicer from Korea may have the same 60 Hz in its characteristics, but if it has a different type of engine, then be prepared for the fact that the device will not turn on. The same applies to any equipment from Korea, Japan, USA.
Here's what else you need to pay attention to when choosing equipment from Korea, Japan, Taiwan, the USA and a number of other countries - the requirements for the magnitude of the supply voltage! In many countries that produce equipment (Korea, Japan, etc.), the power grids have an operating voltage of 110 V, and not 220, as we have. You can turn on a device designed for 110 V without a transition transformer only once - the first and last ... at best, the device will “burn out”, at worst, it will explode right in your hands! Therefore, if the juicer is from Korea or another country, and has an operating voltage of 110V, then such a device is not suitable for our networks. When choosing a cold-pressed juicer, pay attention to the operating voltage of the device - it must be 220V!
Equipment for Russian networks
For those for whom our article did not seem convincing, there are analogues of the most popular equipment on the market, created specifically for Russian conditions. This technique is represented by a brand with a large assortment of innovative technologies for life. High power, new generation cold pressed, and more can be purchased without fear that there will be a mismatch with the local power grid. The products of this brand have the best value for money, and also offer solutions for the private segment and for small businesses.
Hz (Hertz)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 50 times per second electricity 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.
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.
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.
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.
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.
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.
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.
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 necks from glass bottles. 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.
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 appearance it is not difficult to determine the operating voltage of the overhead line.
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 HPPs in the system, but what can you do - water resources 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?
