GOST current transformers general technical specifications. Current transformers general technical specifications. General technical conditions
Page 1 of 7
GOST 7746-2001
UDC 621.314.224:006.354 Group E64
INTERSTATE STANDARD
CURRENT TRANSFORMERS General technical conditions
ISS 17.220.20
OKP 34 1440
Current transformers. General specifications
Date of introduction 2003-01-01
Preface
1 DEVELOPED by Open Joint Stock Company OJSC Sverdlovsk Current Transformer Plant
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 20 of November 1, 2001)
The following voted for adoption:
State name |
Name of the national standardization body |
|
Azerbaijan Republic Republic of Armenia Republic of Belarus Republic of Georgia Republic of Kazakhstan Kyrgyz Republic Republic of Moldova Russian Federation Republic of Tajikistan Turkmenistan Republic of Uzbekistan Ukraine |
Azgosstandart Armgosstandart Gosstandart of Belarus Gruzstandart |
3 This standard meets the requirements of the international standard IEC 44-1:1996 “Measuring transformers. Part 1. Current transformers"
4 By Decree of the State Committee of the Russian Federation for Standardization and Metrology dated March 13, 2002 No. 92-st, the interstate standard GOST 7746-2001 was put into effect directly as the state standard of the Russian Federation from January 1
2003
5 INSTEAD GOST 7746-89
1 area of use
This standard applies to electromagnetic current transformers (hereinafter referred to as transformers) with a rated voltage from 0.66 to 750 kV inclusive, intended for transmitting a signal of measurement information to measuring, protection, automation, signaling and control devices in alternating current electrical circuits with a frequency of 50 or 60 Hz .
Additional requirements for certain types of transformers in connection with the specifics of their design or purpose (for example, for cascade transformers, transformers designed to operate with standardized accuracy in transient modes, for installation in complete switchgears (switchgear), phase-shielded current conductors) should be established in the standards , technical specifications, agreements or contracts (hereinafter referred to as standards) for specific types of transformers.
The standard does not apply to laboratory, zero-sequence, summing, blocking, and saturable transformers.
2 Normative references
This standard uses references to the following standards:
GOST 2.601-95 Unified system of design documentation. Operational documents GOST 8.217-87 State system for ensuring the uniformity of measurements. Current transformers. Verification method
GOST 12.2.007.0-75 System of occupational safety standards. Electrical products. General safety requirements
GOST 12.2.007.3-75 System of occupational safety standards. Electrical devices for voltages above 1000 V. Safety requirements
GOST 12.3.019-80 System of occupational safety standards. Electrical tests and measurements. General safety requirements
GOST 15.001-881) System for developing and putting products into production. Products for industrial and technical purposes
1) GOST R 15.201-2000 is in force in the Russian Federation.
GOST 15.309-98 System for developing and launching products into production. Testing and acceptance of manufactured products. Basic provisions
GOST 27.003-90 Reliability in technology. Composition and general rules for specifying reliability requirements
GOST 403-73 Electrical devices for voltages up to 1000 V. Permissible heating temperatures for parts of devices
GOST 1516.1-76 AC electrical equipment for voltages from 3 to 500 kV. Requirements for electrical insulation strength
GOST 1516.2-97 Electrical equipment and electrical installations of alternating current for voltage 3 kV and higher. General test methods for electrical insulation strength
GOST 1516.3-96 AC electrical equipment for voltages from 1 to 750 kV. Requirements for electrical insulation strength
GOST 2933-931) Low-voltage electrical devices. Test methods
1) GOST 2933-83 is in force in the Russian Federation.
GOST 3484.1-88 Power transformers. Electromagnetic Test Methods
GOST 3484.5-88 Power transformers. Tank leak testing
GOST 6581-75 Liquid electrical insulating materials. Electrical Test Methods
GOST 8024-90 Apparatus and electrical devices for alternating current voltage
over 1000 V. Heating rate during continuous operation and test methods
GOST 9920-89 (IEC 694-80, IEC 815-86) AC electrical installations for voltage
from 3 to 750 kV. External insulation creepage distance
GOST 10434-82 Electrical contact connections. Classification. General technical
requirements
GOST 13109-97 Electrical energy. Electromagnetic compatibility of technical equipment. Standards for the quality of electrical energy in general-purpose power supply systems
GOST 14192-96 Marking of cargo
GOST 15150-69 Machines, instruments and other technical products. Versions for different climatic regions. Categories, operating, storage and transportation conditions regarding the impact of environmental climatic factors
GOST 15543.1-89 Electrical products. General requirements regarding resistance to climatic external influences
GOST 15963-79 Electrical products for areas with tropical climates. General technical requirements and test methods
GOST 16504-81 System of state testing of products. Testing and quality control of products. Basic terms and definitions
GOST 16962.1-89 (IEC 68-2-1-74) Electrical products. Test methods for resistance to climatic external influences
GOST 16962.2-90 Electrical products. Test methods for resistance to mechanical external influences
GOST 17516.1-90 Electrical products. General requirements regarding resistance to mechanical external influences
GOST 18425-73 Filled transport containers. Free fall impact test method
GOST 18685-73 Current and voltage transformers. Terms and Definitions
GOST 19880-74 Electrical engineering. Basic concepts. Terms and Definitions
GOST 20074-83 Electrical equipment and electrical installations. Method for measuring partial discharge characteristics
GOST 20690-75 AC electrical equipment for voltage 750 kV. Requirements for electrical insulation strength
GOST 21130-75 Electrical products. Grounding clamps and grounding signs. Design and dimensions
GOST 21242-75 Flat and pin contact terminals for electrical devices. Main Dimensions
GOST 23216-78 Electrical products. Storage, transportation, temporary anti-corrosion protection, packaging. General requirements and test methods
RMG 29-99 State system for ensuring the uniformity of measurements. Metrology. Basic terms and definitions
3 Definitions
The terms used in this standard and their corresponding definitions are according to RMG 29, GOST 16504, GOST 18685, GOST 19880, as well as the following:
3.1 nominal safety factor of devices: The ratio of the rated safety current of the devices to the rated primary current of the transformer.
3.2 rated safety current of devices: The minimum value of the transformer primary current at which the total error is at least 10% at the rated secondary load.
3.3 type approval test: A type of state metrological control of a newly developed transformer, carried out in order to ensure the uniformity of measurements, approve the type of transformer and enter it into the State Register of Measuring Instruments.
3.4 type approval test: A type of state metrological control carried out periodically in order to determine the conformity of transformers released from production to the approved type.
3.5 permissible error range: The area beyond which transformer errors should not extend.
4 Classification
4.1 Transformers are divided according to the following main characteristics:
4.1.1 By type of installation (location category and climatic version) according to GOST 15150. When placing transformers inside the shells of complete products, the placement categories must correspond to those indicated in Table 1.
Table 1 - Categories of placement of transformers installed inside the shells of complete products
4.1.2 By design principle: support, walk-through, busbar, built-in, detachable. A combination of several of the listed features in the design of a transformer is allowed, and
also a special design.
4.1.3 By type of insulation: with cast insulation, with a porcelain cover, in a plastic case, with solid insulation (except porcelain and cast) or with a polymer cover, oil-filled, gas-filled.
4.1.4 According to the number of transformation stages: single-stage, cascade.
4.1.5 By the number of secondary windings: with one secondary winding, with several secondary windings.
4.1.6 According to the purpose of the secondary windings: for measurement and metering, for protection 1-1, for measurement and protection, for operation with standardized accuracy in transient modes.
1- Hereinafter, the word “protection” means protection, automation, control and alarm.
4.1.7 By the number of transformation ratios: with one transformation ratio, with several transformation ratios obtained by changing the number of turns of the primary and/or secondary windings, as well as by using several secondary windings with different numbers of turns, corresponding to different values of the rated secondary current.
4.1.8 Features according to 4.1.2, 4.1.3, 4.1.4, 4.1.6 and their designations are given in tables 2 - 4.
table 2
Transformer design |
Symbol |
|
Passage | |
|
Built-in | |
|
Sectional | |
|
Single stage | |
|
Cascade |
Table 3
Type of insulation |
Symbol |
|
With porcelain cover | |
|
With solid and air insulation, with polymer cover Back |
UDC 621.314.224:006.354 Group E64
INTERSTATE STANDARD
CURRENT TRANSFORMERS
General technical conditions
Current transformers. General specifications
ISS 17.220.20
Date of introduction 2003-01-01
Preface
1 DEVELOPED by Open Joint Stock Company OJSC Sverdlovsk Current Transformer Plant
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Minutes No. 20 of November 1.)
|
State name |
Name of the national standardization body |
|
The Republic of Azerbaijan |
Azgosstandart |
|
Republic of Armenia |
Armgosstandard |
|
Republic of Belarus |
State Standard of Belarus |
|
Republic of Georgia |
Gruzstandart |
|
The Republic of Kazakhstan |
Gosstandart of the Republic of Kazakhstan |
|
Republic of Kyrgyzstan |
Kyrgyzstandard |
|
The Republic of Moldova |
Moldovastandard |
|
Russian Federation |
Gosstandart of Russia |
|
The Republic of Tajikistan |
Tajikstandard |
|
Turkmenistan |
Main State Service "Turkmenstandartlary" |
|
The Republic of Uzbekistan |
Uzgosstandart |
|
State Standard of Ukraine |
3 This standard meets the requirements of the international standard IEC 44-1:1996 “Measuring transformers. Part 1. Current transformers"
4 Resolution of the State Committee of the Russian Federation for Standardization and Metrology dated March 13. No. 92-st interstate standard GOST 7746-2001 came into force directly as a state standard of the Russian Federation on January 1.
5 INSTEAD GOST 7746-89
1 area of use
This standard applies to electromagnetic current transformers (hereinafter referred to as transformers) with a rated voltage from 0.66 to 750 kV inclusive, intended for transmitting a signal of measurement information to measuring, protection, automation, signaling and control devices in alternating current electrical circuits with a frequency of 50 or 60 Hz .
Additional requirements for certain types of transformers in connection with the specifics of their design or purpose (for example, for cascade transformers, transformers designed to operate with standardized accuracy in transient modes, for installation in complete switchgears (switchgear), phase-shielded current conductors) should be established in the standards , technical specifications, agreements or contracts (hereinafter referred to as standards) for specific types of transformers.
The standard does not apply to laboratory, zero-sequence, summing, blocking, and saturable transformers.
GOST 2.601-95 Unified system of design documentation. Operational documents
GOST 8.217-87 State system for ensuring the uniformity of measurements. Current transformers. Verification method
GOST 12.2.007.0-75 System of occupational safety standards. Electrical products. General safety requirements
GOST 12.2.007.3-75 System of occupational safety standards. Electrical devices for voltages above 1000 V. Safety requirements
GOST 12.3.019-80 System of occupational safety standards. Electrical tests and measurements. General safety requirements
GOST 15.001-881) System for developing and putting products into production. Products for industrial and technical purposes
1) GOST R 15.201-2000 is in force in the Russian Federation.
GOST 15.309-98 System for developing and launching products into production. Testing and acceptance of manufactured products. Basic provisions
GOST 27.003-90 Reliability in technology. Composition and general rules for specifying reliability requirements
GOST 403-73 Electrical devices for voltages up to 1000 V. Permissible heating temperatures for parts of devices
GOST 1516.1-76 AC electrical equipment for voltages from 3 to 500 kV. Requirements for electrical insulation strength
GOST 1516.2-97 Electrical equipment and electrical installations of alternating current for voltage 3 kV and higher. General test methods for electrical insulation strength
GOST 1516.3-96 AC electrical equipment for voltages from 1 to 750 kV. Requirements for electrical insulation strength
GOST 2933-931) Low-voltage electrical devices. Test methods
1) GOST 2933-83 is in force in the Russian Federation.
GOST 3484.1-88 Power transformers. Electromagnetic Test Methods
GOST 3484.5-88 Power transformers. Tank leak testing
GOST 6581-75 Liquid electrical insulating materials. Electrical Test Methods
GOST 8024-90 AC apparatus and electrical devices for voltages above 1000 V. Heating rate for continuous operation and test methods
GOST 9920-89 (IEC 694-80, IEC 815-86) AC electrical installations for voltages from 3 to 750 kV. External insulation creepage distance
GOST 10434-82 Electrical contact connections. Classification. General technical requirements
GOST 13109-97 Electrical energy. Electromagnetic compatibility of technical equipment. Standards for the quality of electrical energy in general-purpose power supply systems
GOST 14192-96 Marking of cargo
GOST 15150-69 Machines, instruments and other technical products. Versions for different climatic regions. Categories, operating, storage and transportation conditions regarding the impact of environmental climatic factors
GOST 15543.1-89 Electrical products. General requirements regarding resistance to climatic external influences
GOST 15963-79 Electrical products for areas with tropical climates. General technical requirements and test methods
GOST 16504-81 System of state testing of products. Testing and quality control of products. Basic terms and definitions
GOST 16962.1-89 (IEC 68-2-1-74) Electrical products. Test methods for resistance to climatic external influences
GOST 16962.2-90 Electrical products. Test methods for resistance to mechanical external influences
GOST 17516.1-90 Electrical products. General requirements regarding resistance to mechanical external influences
GOST 18425-73 Filled transport containers. Free fall impact test method
GOST 18685-73 Current and voltage transformers. Terms and Definitions
GOST 19880-74 Electrical engineering. Basic concepts. Terms and Definitions
GOST 20074-83 Electrical equipment and electrical installations. Method for measuring partial discharge characteristics
GOST 20690-75 AC electrical equipment for voltage 750 kV. Requirements for electrical insulation strength
GOST 21130-75 Electrical products. Grounding clamps and grounding signs. Design and dimensions
GOST 21242-75 Flat and pin contact terminals for electrical devices. Main Dimensions
GOST 23216-78 Electrical products. Storage, transportation, temporary anti-corrosion protection, packaging. General requirements and test methods
RMG 29-99 State system for ensuring the uniformity of measurements. Metrology. Basic terms and definitions
3 Definitions
The terms used in this standard and their corresponding definitions are according to RMG 29, GOST 16504, GOST 18685, GOST 19880, as well as the following:
3.1 rated safety factor of devices: The ratio of the rated safety current of devices to the rated primary current of the transformer.
3.2 rated safety current of devices: The minimum value of the primary current of a transformer at which the total error is at least 10% at the rated secondary load.
3.3 test for type approval: Type of state metrological control of a newly developed transformer, carried out in order to ensure uniformity of measurements, approve the type of transformer and enter it into the State Register of Measuring Instruments.
3.4 test for compliance with the approved type: A type of state metrological control carried out periodically in order to determine the conformity of transformers released from production to the approved type.
3.5 permissible error range: The area beyond which transformer errors should not extend.
4 Classification
4.1 Transformers are divided according to the following main characteristics:
4.1.1 By type of installation (location category and climatic version) according to GOST 15150.
When placing transformers inside the shells of complete products, the placement categories must correspond to those indicated in Table 1.
4.1.2 By design principle: support, walk-through, busbar, built-in, detachable.
A combination of several of the listed features in the transformer design, as well as a special design, is allowed.
4.1.3 By type of insulation: with cast insulation, with a porcelain cover, in a plastic case, with solid insulation (except porcelain and cast) or with a polymer cover, oil-filled, gas-filled.
4.1.4 According to the number of transformation stages: single-stage, cascade.
4.1.5 By the number of secondary windings: with one secondary winding, with several secondary windings.
4.1.6 According to the purpose of the secondary windings: for measurement and metering, for protection1), for measurement and protection, for operation with standardized accuracy in transient modes.
4.1.7 By the number of transformation ratios: with one transformation ratio, with several transformation ratios obtained by changing the number of turns of the primary and/or secondary windings, as well as by using several secondary windings with different numbers of turns, corresponding to different values of the rated secondary current.
4.1.8 Features according to 4.1.2, 4.1.3, 4.1.4, 4.1.6 and their designations are given in tables 2 - 4.
table 2
Table 3
Table 4
5 Basic parameters
5.1 Transformer ratings:
a) rated voltage of the transformer Unom (except for built-in transformers);
b) rated primary current of the transformer I1nom;
c) rated secondary current of the transformer I2nom;
d) nominal transformer ratio nnom, determined by the formula
e) rated secondary load S2nom with power factor cos ??2 = 1 or cos ??2 = = 0.8| - |S2nom (secondary load designation Z2nom is allowed);
f) accuracy class of the transformer (for a transformer with one secondary winding) or secondary windings (for a transformer with several secondary windings);
g) rated maximum factor of the secondary winding intended for protection, Knom
i) the nominal safety factor of devices of the secondary winding intended for measurement, -KBnom;
GOST 7746-2001
INTERSTATE STANDARD
CURRENT TRANSFORMERS
General technical conditions
INTERSTATE COUNCIL
ON STANDARDIZATION, METROLOGY AND CERTIFICATION
Minsk
Preface
1 DEVELOPED by Open Joint Stock Company OJSC Sverdlovsk Current Transformer Plant
INTRODUCED by Gosstandart of Russia
2 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 20 of November 1, 2001)
|
State name |
Name of the national standardization body |
|
The Republic of Azerbaijan |
Azgosstandart |
|
Republic of Armenia |
Armgosstandard |
|
Republic of Belarus |
State Standard of Belarus |
|
Republic of Georgia |
Gruzstandart |
|
The Republic of Kazakhstan |
Gosstandart of the Republic of Kazakhstan |
|
Republic of Kyrgyzstan |
Kyrgyzstandard |
|
The Republic of Moldova |
Moldovastandard |
|
Russian Federation |
Gosstandart of Russia |
|
The Republic of Tajikistan |
Tajikstandard |
|
Turkmenistan |
Main State Service "Turkmenstandartlary" |
|
The Republic of Uzbekistan |
Uzgosstandart |
|
Ukraine |
State Standard of Ukraine |
3 This standard meets the requirements of the international standard IEC 44-1:1996 “Measuring transformers. Part 1. Current transformers"
4 By Decree of the State Committee of the Russian Federation for Standardization and Metrology dated March 13, 2002 No. 92-st, the interstate standard GOST 7746-2001 was put into effect directly as the state standard of the Russian Federation on January 1, 2003.
5 INSTEAD GOST 7746-89
Content
INTERSTATE STANDARD
CURRENT TRANSFORMERS
General technical conditions
Current transformers.General specifications
date introduction 2003-01-01
1 area of use
This standard applies to electromagnetic current transformers (hereinafter referred to as transformers) with a rated voltage from 0.66 to 750 kV inclusive, intended for transmitting a signal of measurement information to measuring, protection, automation, signaling and control devices in alternating current electrical circuits with a frequency of 50 or 60 Hz .
Additional requirements for certain types of transformers in connection with the specifics of their design or purpose (for example, for cascade transformers, transformers designed to operate with standardized accuracy in transient modes, for installation in complete switchgears (switchgear), phase-shielded current conductors) should be established in the standards , technical specifications, agreements or contracts (hereinafter referred to as standards) for specific types of transformers.
The standard does not apply to laboratory, zero-sequence, summing, blocking, and saturable transformers.
2 Normative references
This standard uses references to the following standards:
GOST 2.601-95 Unified system of design documentation. Operational documents
GOST 8.217-87 State system for ensuring the uniformity of measurements. Current transformers. Verification method
GOST 12.2.007.0-75 System of occupational safety standards. Electrical products. General safety requirements
GOST 12.2.007.3-75 System of occupational safety standards. Electrical devices for voltages above 1000 V. Safety requirements
GOST 12.3.019-80 System of occupational safety standards. Electrical tests and measurements. General safety requirements
GOST 15.001-88 1) System for developing and putting products into production. Products for industrial and technical purposes
____________
1) GOST R 15.201-2000 is in force in the Russian Federation.
GOST 15.309-98 System for development and production of products. Testing and acceptance of manufactured products. Basic provisions
GOST 27.003-90 Reliability in technology. Composition and general rules for specifying reliability requirements
GOST 403-73 Electrical devices for voltages up to 1000 V. Permissible heating temperatures for parts of devices
GOST 1516.1-76 AC electrical equipment for voltages from 3 to 500 kV. Requirements for electrical insulation strength
GOST 1516.2-97 Electrical equipment and electrical installations of alternating current for voltage 3 kV and higher. General test methods for electrical insulation strength
GOST 1516.3-96 AC electrical equipment for voltages from 1 to 750 kV. Requirements for electrical insulation strength
GOST 2933-93 1) Low-voltage electrical devices. Test methods
__________
1) In the Russian Federation, GOST 2933-83 is in force.
GOST 3484.1-88 Power transformers. Electromagnetic Test Methods
GOST 3484.5-88 Power transformers. Tank leak testing
GOST 6581-75 Liquid electrical insulating materials. Electrical Test Methods
GOST 8024-90 AC apparatus and electrical devices for voltages above 1000 V. Heating rate for continuous operation and test methods
GOST 9920-89 (IEC 694-80, IEC 815-86) AC electrical installations for voltages from 3 to 750 kV. External insulation creepage distance
GOST 10434-82 Electrical contact connections. Classification. General technical requirements
GOST 13109-97 Electrical energy. Electromagnetic compatibility of technical equipment. Standards for the quality of electrical energy in general-purpose power supply systems
GOST 14192-96 Marking of cargo
GOST 15150-69 Machines, instruments and other technical products. Versions for different climatic regions. Categories, operating, storage and transportation conditions regarding the impact of environmental climatic factors
GOST 15543.1-89 Electrical products. General requirements regarding resistance to climatic external influences
GOST 15963-79 Electrical products for areas with tropical climates. General technical requirements and test methods
GOST 16504-81 System of state testing of products. Testing and quality control of products. Basic terms and definitions
GOST 16962.1-89 (IEC 68-2-1-74) Electrical products. Test methods for resistance to climatic external influences
GOST 16962.2-90 Electrical products. Test methods for resistance to mechanical external influences
GOST 17516.1-90 Electrical products. General requirements regarding resistance to mechanical external influences
GOST 18425-73 Filled transport containers. Free fall impact test method
GOST 18685-73 Current and voltage transformers. Terms and Definitions
GOST 19880-74 Electrical engineering. Basic concepts. Terms and Definitions
GOST 20074-83 Electrical equipment and electrical installations. Method for measuring partial discharge characteristics
GOST 20690-75 AC electrical equipment for voltage 750 kV. Requirements for electrical insulation strength
GOST 21130-75 Electrical products. Grounding clamps and grounding signs. Design and dimensions
GOST 21242-75 Flat and pin contact terminals for electrical devices. Main Dimensions
GOST 23216-78 Electrical products. Storage, transportation, temporary anti-corrosion protection, packaging. General requirements and test methods
RMG 29-99 State system for ensuring the uniformity of measurements. Metrology. Basic terms and definitions
3 Definitions
The terms used in this standard and their corresponding definitions are according to RMG 29, GOST 16504, GOST 18685, GOST 19880, as well as the following:
3.1 nominal safety factor of devices : The ratio of the rated safety current of the appliances to the rated primary current of the transformer.
3.2 rated safety current of devices : The minimum value of the transformer primary current at which the total error is at least 10% at the rated secondary load.
3.3 type approval test: A type of state metrological control of a newly developed transformer, carried out in order to ensure the uniformity of measurements, approve the type of transformer and enter it into the State Register of Measuring Instruments.
3.4 type approval test: A type of state metrological control carried out periodically in order to determine the conformity of transformers released from production to the approved type.
3.5 permissible error range: The area beyond which transformer errors should not extend.
(ST SEV 2733-80,
MPEI 44-4 (1980),
IEC 185 (1987)
Official publication
USSR STATE COMMITTEE ON STANDARDS Moscow
UDC 621.314.224:006.354 Group E64
STATE STANDARD OF THE USSR UNION
CURRENT TRANSFORMERS General technical conditions
Current transformers. General specifications
(ST SEV 2733-80, IEC 44-4 (1980), IEC 185 (1987)
Valid from 01/01/90 to 01/01/95
Failure to comply with the standard is punishable by law
This standard applies to electromagnetic current transformers (hereinafter referred to as transformers) with a rated voltage from 0.66 to 750 kV inclusive, intended for transmitting a signal of measuring information to measuring instruments and (or) protection and control devices in alternating current installations with a frequency of 50 or 60 Hz , manufactured for the needs of the national economy and export.
The standard does not apply to laboratory, reference, zero-sequence, summing, blocking and saturable transformers.
The terms used in this standard are in accordance with GOST 18685, GOST 16504.
Official edition E
Reproduction is prohibited
© Standards Publishing House, 1989
rated current 5 A, intended for commercial electricity metering.
2. Accuracy classes Q.2S and 0.55 may be used by agreement between the manufacturer and the consumer for transformers, the technical specifications for which were approved after the introduction of this standard.
Errors should not go beyond the boundaries of broken lines consisting of segments drawn through the points of permissible errors.
For transformers with secondary load ratings greater than 60 VA, the lower secondary load limit shall be 15 VA, with secondary load ratings of 1; 2; 2.5; 3; 5 and 10 V-A lower limit of secondary loads - 0.8; 1.25; 1.5; 1.75; 3.75 and 3.75 VA respectively.
3.4.3. The permissible error limits of the secondary windings for protection under operating conditions of use according to clause 3.4.1 in steady state must correspond to those indicated in the table. 4.
Table 4
3.4.4. Metrological characteristics of transformers (secondary windings of transformers) for protection, designed to operate with standardized accuracy in transient modes, and methods for testing them should be established in the standards for specific types of transformers.
3.4.5. By agreement between the consumer and the manufacturer, the operational documentation for transformers must indicate the dependence of the errors on the influencing factors of the primary current, secondary load, frequency and temperature, as well as dynamic characteristics. Dependences of errors on each influencing factor are given at the nominal value of all other influencing factors and are provided with an indication of the accuracy of their determination.
3.5. Heating Requirements
3.5.1. With regard to heating during continuous operation of the flow of the highest operating primary currents (rated currents of long-term operation), transformers (with the exception of built-in ones operating in transformer oil) for rated voltages St. 0.66 kV must meet the requirements of GOST
1. CLASSIFICATION
S. 2 GOST 7746-“9
1.1. Transformers are divided according to the following main characteristics.
1.1.1. By type of installation:
for work in enclosed spaces (location categories 3 and 4 according to GOST 15150);
for work inside electrical equipment enclosures (placement categories - in accordance with Table 1).
Characteristics of the environment inside the shell
1.1.2. According to the design principle: support (O), pass-through (P), busbar (W), built-in (B), detachable (P).
A combination of several of the listed principles in the design of a transformer is allowed, as well as a special design that does not fall under the listed characteristics.
1.1.3. By type of insulation: with cast insulation (L), with porcelain cover (F), with solid insulation (except porcelain and cast) (T), oil-filled (M), gas-filled (G).
1.1.4. According to the number of transformation stages: single-stage, cascade.
1.1.5. According to the number of secondary windings: with one secondary winding, with several secondary windings.
1.1.6. According to the purpose of the secondary windings: for measurement, for protection, for measurement and protection, for operation with standardized accuracy in transient modes.
1.1.7. According to the number of transformation ratios: with one transformation ratio, with several transformation ratios obtained by changing the number of turns of the primary
GOST 7746-8" P. 3
nal and/or secondary windings, as well as by using several secondary windings with different numbers of turns corresponding to different values of the rated secondary current.
2. BASIC (NOMINAL) PARAMETERS
2.1. The nominal parameters of the transformer include:
1) rated voltage of the transformer U Nom (except for built-in ones);
2) rated primary current of the transformer /vol/
3) rated secondary current of the transformer / 2 „ ohm;
4) rated transformation ratio of the transformer
** nom- T~ 1 >
5) rated secondary load with power factor cos 6) nominal accuracy class of the transformer (for a transformer with one secondary winding) or secondary winding (for a transformer with several secondary windings); 7) nominal maximum multiplicity of the secondary winding intended for protection, /Snom/ 8) the nominal safety factor of the devices of the secondary winding intended for measurement, /(in nominal, if a nominal maximum multiplicity is not established for it (for transformers, the technical specifications for which were approved after the introduction of this standard); 9) nominal frequency /nom = 50 or 60 Hz. Note. The rated safety factor of devices is the ratio of the rated safety current of devices to the rated primary current of the transformer. The rated safety current of devices is the primary current at which the total error is at least 10% at the rated secondary load. 2.2. The values of the nominal parameters specified in clause 2.1 should be selected from those given in table. 2. table 2 S. A GOST 7746-“9 Continuation of the table. 2 Parameter name Parameter value 3 Rated primary current of the transformer Lnom, A 1; 5; 10; 15; 20; 30; 40; 50; 75; 80; 100; 150; 200; 300; 400; 500; 600; 750; 800; 1000; 1200; 1500; 2000; 3000; 4000; 5000; 6000; 8000; 10000; 12000; 14000; 16000; 18000; 20000; 25000; 28000; 30000; 32000; 35000; 40000 4. Rated secondary current* /gnome, A 5. Maximum operating primary current**, / !n p, A See table. 5 6. Rated secondary load 5 2N ohm with cos power factor<р 2 = 1, В А 7. Rated secondary load* S 2H0M, with power factor cos f 2 ^0.8 (inductive), VA** 3; 5; 10; 16; (20): (25); 30; (40); (50); 60; (75); (100) 8. Nominal accuracy class of transformer or secondary winding: for measurement for protection 0.1; 0.2; 0.2S; 0.5; 0.5S 1; 3; 5; 10*** 9. Nominal maximum factor of secondary windings for protection /Snom From 5 to 30. At the request of the consumer, it is allowed to set other values in the standards for specific types of transformers Yu Nominal safety factor of DEVICES K ynom Established in standards for specific types of transformers * The values indicated in brackets should not be used in transformers for which the technical specifications (TOR) were approved after the introduction of this standard. ** The corresponding values of the rated secondary load (Z 2H o M) in ohms are determined from the expression 2NOM That ‘ * ** *** ***Only for built-in transformers with rated primary current Up to 100 A. 2.3. Transformer symbol structure*. T X X x-x x-x-x/x - X/X XX Rated secondary current, A Rated primary current. A (if the transformer has several primary currents, indicate all values through a dash) Nominal accuracy class (if a transformer has several secondary windings, indicate the accuracy class of each of them in the form of a fraction) Design option, if there are several of them (Arabic or Roman numerals) Rated voltage, kV M (only for upgraded products) Designation according to clause 1.1.3 Designation according to clause 1.1.2 Product designation * For transformers for which the technical specifications were approved before the introduction of this standard, it is allowed to use the previously existing designation structure. An example of the designation of the first design version of a reference, oil-filled current transformer for a rated voltage of 330 kV, category B along the length of the leakage distance of external insulation, with five secondary windings of accuracy classes 0.2 and YUR, for a rated primary current of 3000A, rated secondary current of 1A, climatic version U, placement category 1: TOM ZZOB-1-0.2/YUR/lOP/lOPfYUR-3000/1U1 Notes: 1. The letter part of the symbol represents the series; a combination of letter designation, rated voltage value, external insulation category along the creepage distance and design option - type; The above designation in general is the type of transformer. 2. For built-in transformers, a simplified symbol may be used. 3. In the standards for transformers of specific types, it is allowed to introduce additional letters into the letter part, exclude or replace individual letters (except T) to indicate the features of a particular transformer, for example, for transformers designed to operate with standardized accuracy in transient modes. 3. TECHNICAL REQUIREMENTS 3.1. Transformers should be manufactured in accordance with the requirements of this standard, standards or technical specifications for transformers of specific series or types (standards for transformers of specific types) according to working drawings approved in the prescribed manner. Additional requirements for certain types of transformers, for example, for transformers for complete switchgears (KRU), for transformers for phase-shielded current conductors, etc., as well as special requirements for explosion-proof, seismic-resistant, resistant to chemically active environments, etc. transformers for vehicles, for special thermal installations, with gas insulation are indicated in the standards for specific types of transformers. The list of additional reference data for transformers, which, at the customer’s request, should be provided in information materials, is listed in Appendix 1. 3.2. General requirements 3.2.1. Transformers should be manufactured in climatic versions U, UHL, KHL, T or O in accordance with GOST 15150 and GOST 15543. Placement categories in accordance with GOST 15150: 1, 2, 3, 4 - for oil transformers; 1, 2, 3, 4, 5 - for dry transformers. The type of climatic modification and placement category according to GOST 15150 are indicated in the standards for specific types of transformers. Transformers must meet the requirements of GOST 15150 and GOST 15543. In addition, transformers of climatic versions UHL and KhL must meet the requirements of GOST 17412 and regulatory and technical documentation approved in the prescribed manner, and transformers of T and O versions must meet the requirements of GOST 15963. 3.2.2. Transformers must be designed to operate at an installation altitude above sea level of up to 1000 m, with the exception of transformers with a rated voltage of 750 kV, which which must be designed to operate at installation heights of up to 500 m. It is allowed, by agreement between the consumer and the manufacturer, to produce transformers for operation at a height of St. 1000 m, but not more than 3500 m. 3.2.3. Transformers for rated voltage up to 35 kV incl. must be designed for both grounded and grounded electrical systems. and with isolated neutral. Transformers with rated voltages of 110 kV and higher must be designed only for systems with a grounded neutral (with a ground fault factor of 1.4 according to GOST 1516.1). 3.3. Insulation requirements 3.3.1. Insulation of the primary winding (primary circuit) of transformers for rated voltages from 3 to 500 kV inclusive. must meet the requirements of GOST 1516.1, and for a rated voltage of 750 kV - the requirements of GOST 20690. The insulation of the primary winding (primary circuit) of transformers with a rated voltage of 0.66 kV must withstand a test voltage of 3 kV * frequency 50 Hz for 1 min. Additional insulation requirements for placement category 2 transformers that have their own primary winding, determined by moisture condensation (dew), should be specified in the standards for specific types of transformers. 3.3.2. For transformers of placement category 1, the leakage distance of external insulation is established according to GOST 9920. The transformer category, depending on the length of the creepage path (A, B or C), is indicated in the standards for specific types of transformers. 3.3.3. Intersectional insulation of sections of primary and secondary windings intended to change the transformation ratio of transformers must withstand a test voltage of 3 kV* at a frequency of 50 Hz for 1 minute. 3.3.4. The insulation of the secondary windings of transformers relative to grounded parts, and for transformers with several secondary windings, also relative to each other, must withstand a test voltage of 3 kV* at a frequency of 50 Hz for 1 minute. 3.3.5. The interturn insulation of the transformer windings must withstand, without breakdown or damage for 1 min, the voltage induced in them when a current flows through the primary winding, the value of which must be equal to the rated current. * For transformers, the technical specifications for which were approved before the introduction of this standard - 2 kV. mu current, if the voltage amplitude between the terminals of the open secondary winding does not exceed 4.5 kV* or less than the rated current, while the voltage amplitude between the terminals of the open secondary winding must be 4.5 kV*. During presentation and acceptance tests for transformers for rated voltages up to 10 kV inclusive. and rated primary current up to 6000 A inclusive. It is allowed to reduce the time of exposure to the test voltage to 5 s, if this is specified in the standards for specific types of transformers. 3.3.6. Requirements for the insulation of intermediate windings of cascade transformers are established in the standards for specific types of transformers. 3.3.7. Capacitor paper-oil insulation of the primary windings of transformers must meet the following requirements: intensity of partial discharges at a test voltage of 1.1 -D==: should not exceed 1-10“ p C or at a voltage of 1.3 D== should not exceed 5‘10 -11 C; dielectric loss tangent at temperature (25± ±10)°С and voltage 1.0 should not exceed 0.0035, and its increase at voltage from 0.5 to 1.0 should not exceed embroider 0.0003. For transformers with solid and cast insulation for voltages of 6 kV and higher, the standards for specific types of transformers establish standards for the intensity of partial discharges. 3.4. Metrological characteristics 3.4.1. Operating conditions for the use of transformers: 1) alternating current frequency (50±0.5) Hz or (60±0.5) Hz; 2) primary current - in accordance with clause 3.4.2; 3) the value of the secondary load - in accordance with clause 3.4.2; 4) ambient temperature - in accordance with the standards for specific types of transformers; 5) installation height of transformers above sea level according to clause 3.2.2. 3.4.2. Limits of permissible errors of secondary windings for measurement under operating conditions of use according to clause 3.4.1 with us- * For transformers, the technical specifications for which were approved before the introduction of this standard - 3.5 kV. The current mode must correspond to those indicated in the table. 3. Table 3 Permissible error limit Primary current. Secondary load limit, % of nominal % of nominal They don’t standardize They don’t standardize I They don’t standardize I Notes: 1. Accuracy classes 0.2S and 0.55 only for transformers with secondary
