How does the voltage change in the nominal voltage. Nominal voltage of electric wires

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p align="justify"> When designing the development of the electric line, the power supply for the choice of the nominal voltage is violated at the same time with the power supply for the configuration of the electric line. Nominal line voltage scale electrical tethers GOST 721-77 was installed and the next row was set:

0.38; 3; 6; 10; twenty; 35; 110; 150; 220; 330; 500; 750; 1150 kV.

When choosing a nominal voltage, the wires are insured so global recommendations:

voltages of 6 ... 10 kV are used for industrial, small, and rural support projects; the largest width of such fencing was achieved by a voltage of 10 kV; stosuvanya voltage 6 kV for new objects is not recommended, and may be broken during the reconstruction of the main electrical system due to the presence of high-voltage motors for such a voltage;

Ninі at zv'yazku zі zrostannjam navantazhen of the communal-by-button sector є tendency to increase the voltage of rozpodіlnyh merezh at places up to 20 kV;

the voltage of 35 kV is widely used for the establishment of food centers for rural distribution of 10 kV; at the connection with the increase in tensions of the strong people, the voltage of 110 kV begins to stagnate;

voltages of 110 ... 220 kV are to be installed for the creation of regional distribution networks of wire ropes and for the out-of-town electricity supply of great residents;

voltages of 330 kV and more vicorous for molding system-forming connections with EEC and for proving tension by great power plants.

Historically, our country was formed by two systems of electric voltage lines (110 kV and output). One system 110 (150), 330, 750 kV is typical mainly for Pivnіchny Sunset and partly in the Center and Pivnіchny Caucasus. Another system 110, 220, 500 kV in most of the territory of the region. Here, as an offensive rіven, a voltage of 1150 kV was taken. Electricity transmission of such a voltage was in the 80s of the last century and was intended for the transmission of electricity from Siberia and Kazakhstan to the Urals. In Denmark, the electricity transmission lines of 1150 kV are operated at a voltage of 500 kV. The transfer of power lines to a voltage of 1150 kV will be done later.

Nominal voltage for power transmission lines and the main function of two parameters: tension R, which is transmitted along the line, that line L on yaku tsya tension is transmitted. At the link with cim є kіlka empirical formulas for the choice of the nominal stress of the line, suggested by different authors.

Still's formula

U nom = , kV,

de R, kW, L, km, give acceptable results with values L 250 km ta R 60 MW.

Ilarionov's formula

U nom = ,

de R, MW; L, Km, giving satisfactory results for all scales of nominal voltages from 35 to 1150 kV.

The choice of the nominal voltage of the electric line, which is composed of the main number of lines and substations, is the task of the technical and economic equipment of the various options. Here, ring out, it is necessary to guard the guards both on the power lines, and at the substation. Let us explain with a simple example.

Electric framing is being designed, which is made up of two planters L1і L 2 (Fig. 4.1, but). A previous assessment of the nominal voltage showed that for the main plot, a voltage of 220 kV should be taken, and for the other plot, 110 kV. In this case, it is necessary to equalize two options.

In the first variant (Fig. 4.1, b) the entire treadmill is wired for a voltage of 220 kV. In another option (Fig. 4.1, in) the main yard of the merezha runs on a voltage of 220 kV, and the other yard - on a voltage of 110 kV.

Have another option line W 2 voltage 110 kV and substation 110/10 kV with transformer T be cheaper, lower line W 2 voltage 220 kV and substations 220/10 kV with transformer T 2 first option. Prote substation 220/110/10 kV with autotransformer AT another option would be more expensive, lower substation 220/10 kV with transformer T 1 first option.

a B C)

Rice. 4.1. Scheme ( but) and two options ( b) and ( in) strain gauge

Residual selection of the voltage of the measure will be shown in the result of the adjustment of these variants of voltage. If the vitrate is less than 5% lower, then the next option with a higher rated voltage should be given.

Rated voltage electrical tethers infamous confession snake struma the Russian Federation has established a chinny standard (Table 4.1). Table 4.1

The International Electrical Commission (IEC) recommends standard voltages greater than 1000 for systems with a frequency of 50 Hz, which are listed in Table. 4.2. Table 4.2

Vіdomy a number of tests to design economical zones for blocking power transmission of different voltages. The satisfactory results for the entire scale of the nominal voltage in the range from 35 to 1150 kV are given by an empirical formula, proponed by G. A. Ilarionov:

de L - length of the line, km, P - intensity, which is transmitted, MW. In Russia, two systems of electric voltages have been installed for the electric current of the wind tunnel (110 kV and more): 110-330-750 kV - in the UES of Pivnichny Zakhod and part of the Center - and 110-220-500 kV - in the UES of the central and similar regions of the country ( also item 1.2). For CIC OES, as an offensive rіven, a voltage of 1150 kV was adopted, introduced in GOST 1977. A number of motivated 1150 kV power transmission lines operate on a 500 kV voltage. At the last stage of the development of the EES of Russia, the role of system-operated lines is played by lines 330, 500, 750, for a number of energy systems - 220 kV. The first slab of rozpodіlny merezha zagalnogo koristuvannya є merezі 220, 330 and partly 500 kV, the other stage - 110 and 220 kV; Then the electricity is distributed through the electricity supply to the next few contributors (Div. pp. 4.5–4.9). The smartness of the underlay on the system-forming and rozpodіlnі over the nominal voltage field is due to the fact that with the increase in the width of the tension, the intensity of the power plants and the suffocation of the territory by the electric girders, the stress of the rozpodіlny ryadzhі is increased. Tse means, sho measures, scho to change the functions of the system-creating ones, with the appearance in the energy systems of the most important voltage, step by step “transfer” them to the functions, transforming them into separate ones. Rozpodіlna zagalnogo zagalennya zavzhdya will be behind the step-partial principle of the path of the subsequent "imposition" of the militias kіlkoh naprug. The appearance of an advancing stress level is due to the increase in tension of power plants and to the increase in high voltage. Reworking the borders on the rozpodіlna to bring up to the shortest time the last few lines for the rahunok to the border of the new PS, as well as to change the value of that direct flow of tightness along the lines. When they arena, the ilnias of the enectriculty. Failely Ta Delivine Merozі 500 sq. Vіdmova Vіd Clastical Society Niznalo Sockets Blizzard Blisko Two (500/220/110 kV). Such a trend is confirmed by the state of the art in the technical world of foreign countries, if the lines of the intermediate voltage (220–275 kV) are separated by their own development. Most consequently, such a technical policy is carried out in the energy systems of Great Britain, Italy, Germany and other countries. So, in Great Britain, the transformation of 400/132 kV is becoming wider and wider (the 275 kV line is being conserved), in Nіmechchyna - 380/110 kV (it is being separated at the 220 kV line development), in Italy - 380/132 kV (the 150 kV line is being conserved) and d. The largest width as a rozpodіlnі nabula merezhі 110 kV yak in the UES from the system voltage 220–500 kV, so і 330–750 kV. Pitoma rail line 110 kV to become close to 70% of the total length of the submarine 110 kV and more. At this voltage, there is an electric supply of industrial enterprises and energy hubs, districts, electrification of railroad and pipeline transport; the stench of the upper slab was used to supply electricity to the agricultural sector. A voltage of 150 kV has become more popular in the Kola energy system and is not recommended for use in other regions of the country. Voltages of 6-10–20-35 kV are recognized for rozpodіlnyh merezh at the places industrial undertakings. More important than the width of the voltage is 10 kV; 6 kV strands save their value for their length, but, as a rule, they do not develop and, if possible, are replaced by 10 kV strands. Up to this class, the current in GOST is 20 kV, which has a large width (in one of the central districts of the Moscow metropolitan area). A voltage of 35 kV is to be changed for a 10 kV central heating unit in a strong power supply (more often, a 35 / 0.4 kV transformation is required).

The electric leather mesh is characterized by a nominal voltage, so that it can be installed. The rated voltage ensures the normal operation of electric switches (EP), which can give the greatest economic effect and is determined by the transmitted active sweating that old power transmission line.

GOST 21128-75 introduced the scale of the nominal interphase voltage of electric strings and receivers up to 1000 V in a replacement stream: 220.380, 660 V.

GOST 721-77 introduced the scale of the nominal interphase voltage of the electric wires of the zminny stream over 1000 V:

0,38, 3, 6, 10, 20, 35, 110, 150, 220, 330, 500, 750, 1150.

At the table 2.1. the classification of electric tethers is presented, it is shown rozpodil on the tether of lower (PN), middle (SN), higher (VN), supra-high (SVN) and ultra-high (UNN) voltages.

Navalanthum EP is not imposed by postіnuyu, but Zmіnіnuyuzhev's tricky Vіd Zmіni regimen of the Roboti (thoughts, Vіdpovyuyu before passing the technologian process of the virginity), this dummy at the Meriazhi postіino, schilyu) of the nominal value, Scho Znyuє Yakіst Elektroenergії one Sprichiny. The investigations showed that for the largest electric receivers, the zone is surrounded by the values of the voltage difference

The investigations showed that for a large number of electric receivers, the zone is surrounded by the values of the voltage

As a rule, the voltage on the cob of the line more voltage in the end and depends on the amount of voltage input

For approximating the voltage of the voltage reducer U 2 to the nominal voltage of the electric circuit and the safety of the rated energy of the generator, the voltage of the circuit is set by GOST by 5% more than the nominal one.

Since the primary windings move the transformers without a middle fault, but the same connections are made before the generators are pressed, then their rated voltage

The primary windings of the step-down transformers are 100% slower, such stinks live, so the mind can be beaten

In the rest of the hour, the industrial company releases step-down transformers with a voltage of 110-220 kV with a primary winding that is 5% more than the nominal voltage of the wire.

The secondary windings are like step-down ones, and move the transformers with the help of cords that are completely alive with them. Rated voltage secondary windings may be 5-10% more for the nominal voltage of the gauge

Tse to fight in order to compensate for the drop in tension in the fence. On fig. 2.1 shows the voltage diagram, as a clear illustration of what was said above.

2.2. Electric neutral modes

The zero point (neutral point) of three-phase electric lines can be tightly grounded (Fig. 2.2, a), grounded through a high-resistance support (Fig. 2.2, b) or insulated from the ground (Fig. 2.2, c).

The neutral mode in electric lines up to 1000 V is indicated by the safety of maintenance of the line, and in the lines above 1000 V - uninterrupted power supply, economy and reliability of the operation of electrical installations. According to the rules, I will attach electrical installations (PUE) to a robot of electrical installations with a voltage of up to 1000 V, it is allowed both from a dead-earthed and from an insulated neutral.

Kіnets roboti -

This topic should be divided:

LECTURE 1. GENERAL CHARACTERISTICS OF TRANSMISSION SYSTEMS AND REPAIR OF ELECTRIC ENERGY. MODELING OF ELEMENTS OF ELECTRIC SYSTEMS

Plan ... Basic understanding of that purpose ...

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All topics of which I divided:

Characteristics of the transmission system of electrical energy
The basis of the transmission system of electrical energy from electrical stations, which is being developed, to the great areas of electrical supply and the EEC's sub-station hubs, is composed of

Characteristics of systems for distribution of electrical energy
Appointment of separate measures - delivery of electricity without interruption to people with a voltage of 6-10 kV, distribution of electricity between substations 6-110 / 0.38-35 kV district

Transmission system and distribution of electrical energy
In clause 1.3, a characteristic of transmission systems and a subdivision of EE was introduced. Let's take a look at the relationship between these systems and the butt. Like a butt of a razglyadno simple principle

Neutral mode up to 1000 V with dead-earthed neutral
The largest width - chotiriprovidnі merezhi three-phase struma 380/220, 220/127, 660/380 (fig. 2.3)

Low-voltage wires from insulated neutral
All three wires, yakі know zastosuvannya for living, especially in long-term spozhivachіv for small razgaluzhennosti girders with safety in the girders control of phase isolation. Tse

High-voltage wires from insulated neutral
Spozhivach inclusions line voltage, neutral and ground in symmetrical mode run away. The voltage, as far as the insulation can be seen, is the voltage between the phase and the earth

High-voltage lines with compensated neutral
Tsі merezhi also carry up to the tether from a small struma zamikannya on the ground (Fig. 2.9).

High-voltage wires with dead-earthed neutral
Before such a line, one can see a line with a rated voltage of 110 kV and more great strum ground flicker (&g

Nutrition for self-verification
1. What is the nominal voltage? 2. What is the nominal range of voltages of electrical wires? 3. What is the classification of electric lines with voltage, hoarding of the territory, recognition

LECTURE 3. PRINCIPLES OF STRUCTURAL POWER LINES
Plan 1 repeated lines power transmission. 2. Structural vikonannya repeated lines. 3. Support PL. 4. Provid PL. 5. Thunderstorm

Check power lines
Lines are called lines, which are designated for transmission and distribution of HER by wires, we will lay them on the open air and support them for additional support and insulators. Povіtryanі

Cable lines of power transmission
cable line(CL) - power transmission line, which is from one chi kilkoh parallel cables, vikonana in the way of laying (Fig. 3.12). Chi cable

Nutrition for self-verification
1. How are power transmission lines classified according to the constructive design? 2. What factors determine the choice of the type of LEP? 3. To satisfy all the helpers

Active Opir
Obumovlyuє heating wires (thermal losses) and laying in the material of the strum-conducting conductors and their peretina. For lines with wires of a small cut, wired with colored metal

LEP with steel wires
The main advantage of steel wires is their high mechanical power. Zokrema, timchasovy opir for the development of steel darts 600-700 MPa (60-70 kg/mm2)

Nutrition for self-verification
1. What are the purposes of substitution schemes? Name the advantages and shortcomings of these schemes. 2. Yaka physical reality active support LEP? 3. Yak i do

LECTURE 5. PARAMETERS AND SUBSTITUTION SCHEMES OF TWO-WINDING TRANSFORMER
Plan 1. Appointment, smart designation, winding circuits vector diagrams transformer voltage. 2. Double winding transformers.

Double winding transformers
When switching modes in three-phase electric lines with equal phases, transformers in switching circuits are replaced by a single-phase replacement circuit.

See that recognition of outbuildings
Outbuildings are being looked at to compensate reactive tension Key words: static capacitor banks, shunt reactors, static thyristor compensators (STK) and synchronous.