Technological features of power systems

Rated voltage (U nom) is the effective value of the linear voltage at which electrical installations can operate normally and develop the power indicated in the passport (rated power).

The rated voltage of the network is the voltage that is necessary for normal operation of electrical receivers, it coincides with the rated voltage of the receivers. The rated voltage of the generators, as well as for the secondary windings of transformers, is 5% higher than the rated voltage of the network. This is due to the need to take into account voltage losses caused by the flow of current through the wires of the network and to maintain the nominal voltage at the consumer.

The rated voltages are set to coordinate the operation modes of all elements of the power supply systems, starting from the generators of power stations and ending with the most distant receivers. For the same voltage produce electrical equipment.

According to PUE, there are two voltage categories.before andover 1000 V . The scale of nominal line voltages of electrical installations over 1000 V is determined by GOST 721-77, up to 1000 V - GOST 21128-83 (see tables 1.1 - 1.3).

Table 1.1 - Scale of rated voltages of electrical installations up to 1000 V

Table 1.2 - Scale of rated voltages of electrical installations above 1000 V

Networks and receivers Generators and synchronous compensators Transformers and autotransformers
without RPN with RPN
primary windings secondary windings primary windings secondary windings
(3) (3,15) (3); (3,15) * (3,15); (3,3) - (3,15)
6,3 6; 6,3 * 6,3; 6,6 6; 6,3 * 6,3; 6,6
10,5 10; 10,5 * 10,5; 11 10; 10,5 * 10,5; 11
20; 21 *
- 38,5 35; 36,75 38,5
- - 110; 115 115; 121
(150) - - (165) (158) (158)
- - 220; 230 230; 242
-
- -
- -
- -

Table 1.3 - Classification and application of stresses

Increasing the rated voltage of the network increases the cost of electrical equipment. On the other hand, when the voltage decreases, the power and energy losses increase, as the current increases at the same transmitted power. The approximate dependence of reduced costs on voltage is shown in Figure 1.4.

The voltage at which costs have a minimum is calledrational . Rational voltage depends on the length of the lines and the transmitted power and can be determined:

According to special tables;

By nomogram;

By empirical formulas.

When determining the rational non-standard voltage by empirical formulas (in kV), you can use, for example, the Still formula:

WhereP - the transmitted calculated active power per chain, MW;

L - line length, km.

This formula gives acceptable results whenL ≤ 250 km andP ≤ 60 MW.

AtL ≤ 1000 km andP p ≥ 60 MW in the calculations of the rational voltage can use the formula Zaleski

Also, the Illarionov formula, which gives satisfactory results for a voltage scale from 35 to 1150 kV with large line lengths and considerable powers, especially forP ≥ 1000 MW:

Usually a rational mains voltage is determined for the longest section and (or) the section of the highest power.

The result of the calculation according to the above formulas is a non-standard rational voltage, therefore, after the calculation, two nearest standard voltages are usually scheduled (more and less rational). Finally, the rated voltage of the electrical network is selected by means of a technical and economic comparison. In educational design, it is allowed to round off a rational stress to the nearest standard.

It should be noted that in real design the choice of nominal voltage is very limited.As a rule, the electrical network is not designed from scratch, but is a dynamically developing object. Therefore, the design is reduced to the development of the network when new individual areas need to be tied to an existing network. Under these conditions, the nominal voltage of new sections is largely predetermined by the voltages already present in the area.

STANDARD VOLTAGES

(IEC 60038: 2009, MOD)

Official publication

Standard and Forms 2015

Foreword

The objectives, the basic principles and the order of work on interstate standardization are established by GOST 1.0-92 “Interstate standardization system. The main provisions "and GOST 1.2-2009" Interstate system of standardization. Interstate standards, rules and recommendations on interstate standardization. Rules for the development, acceptance, application, renewal and cancellation "

Standard Information

1 PREPARED BY All-Russian Research Institute of Certification Open Joint-Stock Company (VNIIS OJSC)

2 INTRODUCED by the Federal Agency for Technical Regulation and Metrology.

3 ACCEPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes dated September 30, 2014 Ue 70-P)

The short name of the country on MK (EC0 3166) 004-97

Country code for MK (IS0 3166) 004-97

Abbreviated name of the national standardization body

Ministry of Economy of the Republic of Armenia

Belarus

State Standard of the Republic of Belarus

Kazakhstan

Gosstandart of the Republic of Kazakhstan

Kyrgyzstan

Kyrgyzstandard

Moldova Standard

Rosstamdart

Goslotrebstandart of Ukraine

4 By order of the Federal Agency for Technical Regulation and Metrology dated November 25, 2014 No. 1745-st, the interstate standard GOST 29322-2014 was put into effect as the national standard of the Russian Federation from October 1, 2015.

5 This standard is modified in relation to the international standard IEC 60038: 2009 IEC standard voltages. At the same time, additional and amended provisions, taking into account the needs of the national economy of the above-mentioned states, are indicated in the text in italics, as well as a vertical line located in the margins of this text.

International Standard developed by the International Electrotechnical Commission (IEC).

The name of this standard has been changed relative to the name of the international standard due to the peculiarities of building an interstate standardization system.

Translation from English (a).

Compliance - Modified (MOD)

6 VZAMEN GOST 29322-92

Information about changes to this standard is published in the annual information guide “National Standards”. and the text of the amendment and amendments is the monthly information index “National Standards”. In case of revision (replacement) or cancellation of this standard, the corresponding notice will be published in the monthly information index “National Standards”. Relevant information, notification and texts are also posted in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet

© Standard and Form. 2015

In the Russian Federation, this standard cannot be fully or partially reproduced, replicated and distributed as an official publication without permission from the Federal Agency for Technical Regulation and Metrology.

Introduction

This standard establishes the nominal voltage for electrical systems, networks, circuits and equipment of AC and DC, which are used in the countries - members of the International Electrotechnical Commission.

This standard by construction, the sequence of statement of requirements, the numbering of sections and subsections fully complies with IEC 60038: 2009. Compared to the IEC 60038: 2009 standard, this standard has been updated with updated references to international standards and definitions of terms.

The lowest voltage used in Table A.1 of Appendix A of this standard is defined for the maximum voltage drop between the input to the user's electrical installation and electrical equipment, which is 4%. Such a maximum voltage drop in electrical circuits of electrical installations was indicated in the previously existing standard - 8 Table G.52.1 of the currently valid standard for electrical installations connected to public electric networks, set different values ​​for the maximum voltage drop:

for electric lamps - 3%: for other electrical receivers - 5%.

Requirements in this standard are in plain type, notes are in small straight type. Updated links, as well as additional and modified provisions are in italicized text.

INTERSTATE STANDARD

STANDARD VOLTAGES

Standard voltages

Introduction Date - 2015-10-01

1 area of ​​use

This standard applies to:

On electrical AC systems with a rated voltage of more than 100 V and a standard frequency of 50 Hz or 60 Hz, used for the transmission, distribution and consumption of electricity, and electrical equipment used in such systems:

For AC and DC traction systems:

AC electrical equipment with a rated voltage of less than 120 6 and a frequency (usually, but not only) of 50 or 60 Hz, DC electrical equipment with a rated voltage of less than 750 8. Such equipment includes batteries (from cells or batteries), other power sources AC or DC, electrical equipment (including industrial and communications) and household appliances.

This standard does not apply to voltages used to receive and transmit signals or during measurements. The standard does not apply to standard voltages of components or parts used in electrical devices or electrical equipment.

This standard establishes the standard voltage valueswhich are intended for use as:

Preferred values ​​for the rated voltage of electrical power systems:

Reference values ​​for electrical equipment and designed electrical systems.

Notes

1 Two main reasons resulted in the values ​​specified in this standard:

The values ​​of the nominal voltage (or the highest voltage for electrical equipment) established in this standard are mainly based on the historical development of electrical power systems throughout the world, since these values ​​turned out to be the most common and have received worldwide recognition:

The voltage ranges specified in this standard were recognized as the most suitable as the basis for the development and testing of electrical equipment and systems.

2 However, the determination of appropriate test values, test conditions and acceptance criteria is the task of product standards and standards systems.

2 Terms and definitions

8 of the present standard the following terms are applied with the corresponding definitions. For AC voltages, the effective values ​​are listed below.

nominal system voltage: The corresponding approximate voltage value used to indicate or identify the system.

[section 601-01. article 21] _

Official publication

2.5 supply voltage (supply voltage): Voltage between phases or voltage between phase and neutral at the supply terminals.


2.4 supply terminals: A point in a transmission or distribution electrical network, designated as such and defined by a contract in which the parties to the contract exchange electrical energy.


Note - Equivalent definition: voltage between lines or voltage between line and neutral at the clamp terminals.

2.6 supply voltage range (supply voltage): The voltage range at the power terminals.

2.7 utilization voltage: Voltage between phases or voltage between phase and neutral at receptacles or at points of fixed electrical installations to which receptacles must be connected.

Note - Equivalent definition: voltage between lines or voltage between line and neutral at receptacles or at points of fixed electrical installations to which receptacles must be connected.

2.8 utilization voltage range: The voltage range at the receptacles or at the points of fixed electrical installations to which electrical receivers should be connected.

Note - In some standards for electrical equipment (for example, in IEC 60335-1 and IEC 60071). The term “voltage range” has a different meaning.

2.9 highest voltage for electrical equipment (highest voltage for equipment): The highest voltage for which electrical equipment is described relative to:

a) isolation:

b) other characteristics that may be associated with this highest voltage in the appropriate recommendations for electrical equipment.

Note - Electrical equipment can only be used in electrical systems with the highest voltage that is less than or equal to its highest voltage for electrical equipment.




3 Standard Voltages

3.1 Systems and electrical equipment of alternating current with rated voltage from 100 to 1000 V inclusive

The rated voltage of the AC system in the range from 100 to 1000 V should be chosen from the values ​​given in Table 1.

Table 1 - Systems and electrical equipment of alternating current with rated voltage from 100 to 1000 V inclusive

Rated voltage three-phase three-conductor or three-conductor systems. AT

Rated voltage of single-phase three-wire systems. AT

“The 230/400 V value is the result of the evolution of the 220/330 V and 240/415 V. systems that have completed use in

Europe and in many other countries. However, the 220/360 V and 240/415 V systems are still in use.

* "The 400/690 V value is the result of the 360/660 V. system eooption, which was completed to be used in Europe and in many other countries. However, the 380/660 V system is still in use.

° The value of 200 or 220 V is also used on some countries.

4 ’Values ​​of 100/200 V are also used in some countries in systems with a frequency of 50 or 60 Hz.

8 Table 1 three-phase four-wire systems and single-phase three-wire systems include single-phase electrical circuits connected to these systems.

Smaller values ​​in the first and second columns are the voltages between the phase and the neutral, larger values ​​are the voltages between the phases. If a single value is specified, it refers to three-phase three-wire systems and sets the voltage between the phases. The smaller value in the third column is the voltage between the phase and the neutral, the larger the voltage between the phase conductors.

Stresses greater than 230/400 V.designed for use in heavy industry and in large commercial enterprises.

Under normal operating conditions, the supply voltage should not differ from the nominal system voltage by more than ± 10%.

The range of voltage used depends on the voltage change at the power terminals and the voltage drop, which may be in a consumer electrical installation, for example, the electrical installation of a building. For more information, see. This range of voltage used should be taken into account by the technical committees on standardization.

Note - The highest and lowest voltage values ​​at the power terminals and at the terminals of the power receiver are given in Appendix A for information. They can be calculated as indicated above and on.

3.2 DC and AC traction systems

The voltages of a dc or ac system should be chosen from the values ​​given in Table 2.

Table2 - Traction systems of direct and alternating current * "

In vain not, В_ Nominal frequency for

I smallest

Nominal

The greatest

systems variable g wasp. Hz

DC systems

Single phase systems

alternating current

The values ​​indicated on the brackets are considered as pre-casting and values ​​These values ​​are not recommended for new systems built in the future. In particular, for single-phase AC systems, a voltage of 62SO V should be used only when local conditions do not allow the use of a rated voltage of 25,000 V.

The values ​​indicated in the table are the values ​​adopted by the International Committee on Equipment for Technical Spectacles and Technical Committee 9 of the IEC “Electrical Equipment and Systems for Others *.

* In some European countries, this voltage can reach 4,000 volts. Electrical Equipment: Reds involved in international communication with these countries, must withstand this maximum value “for short periods of time up to S min.

3 3 Three-phase systems and electrical equipment of alternating current with rated voltage from above 1 up to 35 kV inclusive

The voltages for a three-phase AC system with a rated voltage in excess of 1 to 35 kV inclusive should be selected from the values ​​given in Table 3.

Table 3 - Three-phase systems and electrical equipment of alternating current with a nominal voltage in excess of 1 to 35 kV inclusive - "

Highest voltage for

Rated system voltage.

Highest voltage for

Rated voltage

electrical equipment, kV

system. kV


2 in the normal system of row I, the largest and smallest voltages do not differ more than BUT U> approximately) from the system nominal voltage. In a normal system of series II, the highest voltage does not differ by more than 5 5%. and the lowest voltage is more than - 10% of the rated voltage of the system

* "These systems are usually three-way systems, unless otherwise indicated. The values ​​indicated are voltages between phases.

The values ​​indicated in parentheses are considered non-addictive values. These values ​​are not recommended for new systems being built in the future.

** These values ​​should not be used for new general purpose distribution systems.

^ These systems are usually four-wire systems, and the indicated values ​​are voltages between the phases. The voltage between the phase and the neutral is the specified value divided by 1.73.

41 Unification of these values ​​under consideration

“The values ​​of 22.9 kV for the rated voltage and 24.2 or 25.8 kV for the highest voltage for the equipment are also used in some countries

3.4 Three-phase systems and electrical equipment of alternating current with a nominal voltage in excess of 35 to 230 kV inclusive

The voltages for a three-phase AC system with a rated voltage of over 35 kV to 230 kV inclusive should be selected from the values ​​given in Table 4.

Table 4 - Three-phase systems and electrical equipment of alternating current with a nominal voltage in excess of 35 to 230 kV inclusive *

Highest voltage for

Rated system voltage. kV

"Values ​​in brackets are not considered to be preferred terms. These values ​​are not recommended for new systems constructed in the future. Values ​​are voltages and Phases

The above are two kinds of nominal system voltages. In any country, it is recommended to use only one of two rows.

In any country, as the highest voltage for electrical equipment, it is recommended to use only one value from the following groups:

123 or 145 kV;

245 or 300 kV (seetable 5) or 362 kV (see Table 5).

3.5 Three-phase alternating current systems with the highest voltage for electrical equipment over 245 kV

The highest voltage for electrical equipment for a three-phase AC system, exceeding 245 kV, should be chosen from the values ​​given in Table 5.

Table 5 - Three-phase AC systems with the highest voltage for electrical equipment more than 245 kV *:

The highest voltage dpya electrical equipment, kV


"Rolling brackets, about brackets, are considered to be yellow wire rollers. These values ​​are not recommended for new ones: they are used in the future. Values ​​are voltages between phases.

"The value of 526 sq.

A value of 7–5 kV is also used. The voltage values ​​used by the three electrical tests should be those that established the IEC for 765 kV.


In any geographic region, it is recommended to use only one value from the following groups as the highest voltage for electrical equipment:

245 (see Table 4) or 300 or 362 k8:

362 or 420 kV:

420 or 550 kV:

1100 or 1200 kV.

Note - The term “geographic region” can indicate one country, a group of countries that agree to accept the same voltage level, or part of a very large country.

3.6 AC electrical equipment with a rated voltage less than 120 V and DC with a rated voltage less than 750 V

Rated voltage less than 120 and 750 V for electrical equipment, respectively, AC and DC should be selected from the values ​​given in Table 6.

Table 6 - AC electrical equipment with a rated voltage of less than 120 V and DC with a rated voltage of less than 750 V

D.C

Preferred, in

Preferred. AT

Notes

1 Since the voltage of cells or batteries is less than 2.4 V and the choice of the type of the applied> battery or battery for various applications is based on different criteria than is used. these voltages are not listed in the table. The relevant technical committees of the IEC can be gans of cells or batteries and the corresponding voltages for specific trimenenias.

2 For technical and economical reasons, other voltages may be required for specific applications.

Appendix A

(reference)

The largest and smallest values ​​of the voltage at the terminals of power supply and electrical receivers for alternating current systems with a nominal voltage of 100 to 1000 V inclusive

Table A.1 shows the largest and smallest voltages at the power and consumer terminals. They can be calculated according to the data in Table 1, Section 4 of this standard and the instructions given in

Notes

1 The values ​​in Table A.1 are based on a note to section 525. which states: “In the absence of other considerations, it is recommended that in practice the voltage drop between the input to the user's electrical installation and electrical equipment should not exceed 4% of the nominal electrical installation voltage. Section 525 is pending. In the future, the values ​​for the lowest voltage used may be modified in accordance with the revision.

2 Standard replaced by standard. in Table C. 52.1 of Appendix G of which, for electrical installations connected to public electric networks, the following maximum voltage drops are set: for electric luminaires - 3 96. for other electrical devices - 5%.

Table A.1 - The highest and lowest voltage values ​​at the terminals of power supply and consumers for alternating current systems with a rated voltage from 100 to 1000 V inclusive

Voltage

Rated frequency. Hz

Highest supply voltage or

voltage. AT

Rated voltage. AT

The smallest litany. AT

The lowest voltage used. AT

Three phase four wire or

three-way systems

Ediofaea sinprovodiye systems

* The 230/400 V value is the result of the evolution of the 220/360 V and 240/415 V. systems. “The latter have been used in Europe and in many other countries. However, the 220/380 V and 240/415 V systems are still in use.

The value of 400/690 V is the result of the evolution of the 380/660 V. system, which was completed to be used on Europe and


In other countries. However, the 380/660 V system is still being used.

“A value of 200 or 220 V is also used for some countries.

Values ​​of 100/200 V are also used for some countries in systems with a frequency of SO or 60 Hz.


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