Transformers. GOST

•   GOST 8.217-2003   State system for ensuring the uniformity of measurements. Current transformers. Verification procedure
• GOST R 52719-2007   Power transformers. General specifications
• GOST R 51559-2000   Power oil transformers of voltage classes of 110 and 220 kV and autotransformers with a voltage of 27.5 kV for electric railways of alternating current. General specifications
• GOST 23873-79   Transformers electronic-magnetic multifunctional. Main settings
• GOST 23871-79   Transformers electronic-magnetic multifunctional. Terms and Definitions
• GOST 23871-79   Transformers electronic-magnetic multifunctional.
• GOST 22756-77   Transformers (power and voltage) and reactors. Methods for testing the electrical strength of insulation
• GOST 10458-81   Transformers for induction electrothermal installations at a frequency of 500 to 10,000 Hz. Main settings
• GOST 9879-76   Transformers power ship. Main settings
• GOST 9680-77   Power transformers with a capacity of 0,01 kVA and more. A number of nominal capacities
• GOST 8008-75   Power transformers. Test methods for switching devices of winding branches
• GOST 3484.5-88   Power transformers. Tanks for leaks
• GOST 3484.4-88   Power transformers. Test tanks for mechanical strength
• GOST 3484.3-88   Power transformers. Methods for measuring dielectric insulation parameters
• GOST 3484.2-88   Power transformers. Heating tests
• GOST 3484.1-88   Power transformers. Methods of electromagnetic testing
• GOST 20938-75   Low power transformers. Terms and Definitions
• GOST 20243-74   Power transformers. Test methods for short-circuit resistance
• GOST 20247-81   Transformers and electric power transformer power transformers. General specifications
• GOST 26649-85   Transformers hydrodynamic for building and road machines. Acceptance rules and test methods
• GOST 26216-84   Transformers hydrodynamic for building and road machines. Main settings
• GOST 25783-83   Transformers hydrodynamic for building and road machines. Technical requirements
• GOST 24687-81   Power transformers and electric reactors. Degrees of protection
• GOST 19294-84   Low power transformers for general use. General specifications
• GOST 18630-73   Transformers pulse. Main settings
• GOST 18628-73   Single-phase power supply transformers for voltage from 1000 to 35000 V and power up to 4000 V x A.
• GOST 17596-72   Transformers matching low-frequency power up to 25W. Main settings
• GOST 16772-77   Transformers and reactors. General specifications
• GOST 16555-75   Transformers power three-phase hermetic oil. Technical specifications
• GOST 16110-82   Power transformers. Terms and Definitions
• GOST 15542-79   Transformers mine explosion-proof. General specifications
• GOST 14209-85   Power oil transformers of general purpose. Permissible loads
• GOST 11983-81   Transformers signal output horizontal scan for television receivers. General specifications
• GOST 12.2.024-87   Occupational safety standards system. Noise. Power oil transformers. Norms and methods of control
• GOST 12.2.007.2-75 Occupational safety standards system. Power transformers and electric reactors. Safety requirements
• GOST 8.216-88   State system for ensuring the uniformity of measurements. Voltage transformers. Verification procedure
• GOST 4.375-85   System of product quality indicators. Converters, amplifiers, stabilizers and transformers measuring analog. Nomenclature of indicators
• GOST 4.316-85   System of product quality indicators. Transformers power, zero size, measuring. Substations complete transformer. Inputs high-voltage. Nomenclature of indicators
• GOST 21023-75   Power transformers. Methods for measuring the characteristics of partial discharges during tests with a voltage of an industrial frequency

FEDERAL AGENCY
  ON TECHNICAL REGULATION AND METROLOGY
   NATIONAL
  STANDARD
  RUSSIAN
  FEDERATIONS GOST R
52719-2007
  POWER TRANSFORMERS
  General specifications
   Moscow
  Standardinform
2007
  Foreword
  The goals and principles of standardization in the Russian Federation are established by Federal Law No. 184-FZ of December 27, 2002 "On Technical Regulation", and the rules for the application of national standards of the Russian Federation - GOST P 1.0-2004 "Standardization in the Russian Federation. Basic provisions »
  About the standard
  1. DEVELOPED by the Branch of JSC "NTTs Elektroenergetika" - VNIIE, the Federal State Unitary Enterprise "All-Russian Electrotechnical Institute named after I. IN AND. Lenin "(FSUE VEI)
  2. It was introduced by the Technical Committee for Standardization of TC 37 "Electrical Equipment for Transmission, Transformation and Distribution of Electric Power"
  3. APPROVED AND ENABLED The Order of the Federal Agency for Technical Regulation and Metrology of April 9, 2007 No. 60-st
  4. This standard is developed taking into account the main regulations of the following international standards:
  IEC 60076-1 (in terms of basic concepts and definitions);
  IEC 60076-2, IEC 60076-3 and IEC 60076-5 (in terms of technical requirements for heating, electrical strength and short-circuit resistance)
  5. INTRODUCED FOR THE FIRST TIME
  Information on changes to this standard is published in the annually published information index "National Standards", and texts of changes and amendments - in the monthly published information indexes "National Standards". In case of revision (replacement) or cancellation of this standard, the relevant notice will be published in the monthly published information index "National Standards". The 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
  Content
  1 area of ​​use
  2. Normative references
  3. Terms and definitions
  4. Classification
  5 Basic Parameters
  6 Technical requirements
  6.1. Heating Requirements
  6.2. Loading capacity
  6.3. Requirements for dielectric strength of insulation
  6.4. Requirements for durability in case of short circuits and shock shocks
  6.5. Requirements for components
  6.6. Cooling System Requirements
  6.7. Reliability requirements
  6.8. Completeness
  6.9. Marking and packaging
  7. Safety requirements
  8. Environmental protection requirements
  9. Acceptance rules
  10 Methods of control
  11 Transportation and storage
  12. Instructions for use
  13. Manufacturer's warranties
  Appendix A (mandatory) Conditional designation of transformers
  Appendix B (mandatory) Schemes and groups for connecting windings of transformers
  Annex B (compulsory) Protective coatings
  Appendix D (mandatory) Components of transformers
  Appendix D (mandatory) Cooling systems for oil transformers
  Appendix E (compulsory) List of technical data and characteristics specified in the passport of the transformer
  Appendix G (mandatory) Marking of terminals and branches of power transformers
Annex I (mandatory) Testing of oil sample from the oil transformer tank and the on-load tap-changer contactor having arc quenching in oil
  Bibliography
GOST R 52719-2007
  NATIONAL STANDARD OF THE RUSSIAN FEDERATION
  POWER TRANSFORMERS
  General specifications
  Power transformers.
  General specifications
  Date of introduction - 2008-01-01
  1 area of ​​use
  This standard applies to general purpose power transformers, including autotransformers, auxiliary transformers for power plants and transformers for complete transformer substations (KTP), three-phase power not less than 5 kVA and single-phase power of at least 1 kVA of voltage classes up to and including 1150 kV , designed for the needs of the country's economy.
  The standard applies to equipment developed after January 1, 2008.
  The standard does not apply to low-power transformers and special transformers (transformer, electric furnace, traction, starting, welding, etc.), as well as transformers with more than three windings. The requirements of this standard can be fully or partially applied to these transformers, if they do not have separate regulatory documents (hereinafter - ND).
  For those of the specified power transformers, for which there are separate LPs, this standard is only applied to the extent specifically specified in the ND for these transformers.
  NOTE The number of windings of a three-winding transformer is determined from the number of its main windings, i. without regard to the adjusting and compensating windings.
  2. Normative references
  Normative references to the following standards are used in this standard:
  Rail rails. GOST R 51685-2000 Railway rails. General specifications
  Quality management systems. GOST R ISO 9001-2001. Requirements
  Unified system of design documentation. Operational documents
  GOST 9.014-78 Unified system of protection against corrosion and aging. Temporary anticorrosive protection of products. General requirements
  The system of labor safety standards. Fire safety. General requirements
  Occupational safety standards system. Electrotechnical products. General safety requirements
  The system of labor safety standards. Power transformers and electric reactors. Safety requirements
  Occupational safety standards system. Noise. Power oil transformers. Norms and methods of control
  GOST 721-77 Power supply systems, networks, sources, converters and receivers of electrical energy. Rated voltages above 1000 V
  GOST 982-80 Oils transformer. Technical specifications
  Electrical equipment of alternating current for voltage from 1 to 750 kV. Requirements for dielectric strength of insulation
  GOST 3484.1-88 Power transformers. Methods of electromagnetic testing
  GOST 3484.2-88 Power transformers. Heating tests
  Power transformers. GOST 3484.3-88. Methods for measuring dielectric insulation parameters
  GOST 3484.4-88 Power transformers. Test tanks for mechanical strength
  GOST 3484.5-88 Power transformers. Tanks for leaks
  Current transformers. General specifications
  Electrical insulation systems. Evaluation of heat resistance and classification
  GOST 9680-77 Power transformers with a capacity of 0,01 kVA and more. A number of nominal capacities
  GOST 9920-89 (IEC 694-80, IEC 815-86) Electrical installations of alternating current for voltage from 3 to 750 kV. Distance of external insulation leakage path
  Contact electrical connectors. Classification. General technical requirements
  GOST 10693-81 Condensing watertight entries for rated voltages of 110 kV and higher. General specifications
  Electrical energy. Compatibility of technical means is electromagnetic. Norms of quality of electric energy in general-purpose power supply systems
  GOST 14192-96 Marking of goods
  GOST 14209-97 (IEC 354-91) Guidelines for the load of power oil transformers
GOST 14254-96 (IEC 529-89) Degrees of protection provided by enclosures (IP code)
  GOST 15150-69 Machines, devices and other technical products. Versions for different climatic regions. Categories, operating conditions, storage and transportation in terms of the impact of environmental climatic factors
  GOST 15543.1-89 Electrotechnical products. General requirements regarding the resistance to climatic external factors
  GOST 16110-82 Power transformers. Terms and Definitions
  GOST 17516.1-90 Electrotechnical products. General requirements regarding the resistance to mechanical external factors
  GOST 18620-86 Electrotechnical products. Marking
  GOST 20243-74 Power transformers. Test methods for short-circuit resistance
  GOST 21023-75 Power transformers. Methods for measuring the characteristics of partial discharges during tests with a voltage of an industrial frequency
  GOST 21128-83 Power supply systems, networks, sources, converters and receivers of electrical energy. Rated voltages up to 1000 V
  GOST 21130-75 Electrotechnical products. Earthing clamps and grounding marks. Design and dimensions
  GOST 22756-77 Transformers (power and voltage) and reactors. Methods for testing the electrical strength of insulation
  GOST 23216-78 Electrotechnical products. Storage, transportation, temporary anticorrosion protection, packaging. General requirements and test methods
  GOST 23865-79 Condensing watertight entries for rated voltages from 110 kV and higher. Types and sizes
  GOST 24126-80 Devices for regulating the voltage of power transformers under load. General specifications
  GOST 30830-2002 (IEC 60076-1-93) Power transformers. Part 1. General provisions
  NOTE - When using this standard it is advisable to check the operation of reference standards in the public information system - on the official website of the Federal Agency for Technical Regulation and Metrology on the Internet or on the annually published informational index "National Standards", which was published as of January 1 of the current year , and on the corresponding monthly published information signs published this year. If the reference standard is replaced (modified), then when using this standard should be guided by a replacement (modified) standard. If the reference standard is canceled without replacement, then the provision referring to it is applied in the part not affecting this reference.
  3. Terms and definitions
  3.1. In this standard terms are used in accordance with GOST 30830.
  3.2. In this standard, the term "regulatory document" is a document that establishes rules, general principles or characteristics relating to transformers, and includes the concepts: standard, technical conditions, terms of reference, technical specifications and other documents for the supply of products.
  4. Classification
  4.1. Power transformers are classified according to the following characteristics:
  - for working conditions - for transformers intended for operation under normal and special conditions;

Page 3 of 12

3. TECHNICAL REQUIREMENTS

3.1. Transformers must be manufactured in accordance with the requirements of this standard, standards or technical conditions for specific groups and types of transformers according to the working drawings approved in accordance with the established procedure.
   3.2. Design Requirements
   3.2.1. Requirements for heating and load capacity
   3.2.1.1. The excess of the temperature of individual elements of an oil transformer or a transformer with a liquid dielectric above the temperature of the cooling medium (air or water) during the heating tests on the main branch must not exceed the values ​​indicated in Table. eleven.
   Table 11

Notes:
   1. The excess of the temperature of the windings is determined by the method of measuring their resistance to direct current (mean excess of the temperature of the windings).
2.   (Excluded, Amend No. 1).

For triple-wound regimes of transformers, the calculated temperature rise of individual elements should not exceed the values ​​indicated in Table. 11, taking into account the note to paragraph 3.9.3.3. In this case, the excess of the temperature of the upper layers of the oil or other liquid dielectric of the triple winding transformer should be calculated for combining the loads with the greatest total losses, and exceeding the temperature of the windings, the surface of the magnetic system and the elements of the metal structures - for combining the loads that are the most stringent for the element of the transformer under consideration.

3.2.1.2. For oil transformers at a normalized temperature of the cooling water at the inlet to the cooler of more than 25 ° C (but not more than 33 ° C), the average temperature rise of the windings indicated in Table. 11, should be reduced by the difference between the normalized temperature and 25 ° C.
   3.2.1.3. For transformers at certain points of the magnetic system and elements of metal structures, it is allowed to exceed the surface temperature that does not come into contact with solid insulation above the temperature of the cooling medium to 85 ° C, unless this excess exceeds in other operating modes, including non-main branches.

3.2.1.4. For oil transformers with the bolted connection of the contacts of the removable inputs, the temperature of the contacts above the ambient temperature should not exceed:
   85 ° C - for contacts in oil;
   65 ° C - for contacts in the air.
   3.2.1.5. The excess of the temperature of the individual elements of the dry transformer above the temperature of the cooling medium during the heating tests on the main branch must not exceed those indicated in Table. 12.

Table 12

Notes:
   1. The excess of the temperature of the windings (the average excess of the temperature of the windings) is determined by the method of measuring their resistance to direct current.
   2. It is allowed to use separate insulating parts of a lower heat resistance class than the class of heat resistance of windings in general, if it is proved by tests that the temperature of the most heated points of insulating parts of lower classes does not exceed the values ​​admissible for these classes in accordance with GOST 8865.

(Changed edition, Amendment No. 1).

3.2.1.6. With steady short-circuit currents in accordance with paragraph 3.3.1, the temperature of the windings, calculated from the initial temperature equal to the sum of the maximum temperature of the cooling medium in accordance with paragraphs 1.2, 1.3 and the winding temperature exceeding Table 3. 11, should not exceed the values ​​indicated in Table. 13.

Table 13

3.2.1.7. Under the load capacity is understood the property of the transformer to carry a load in excess of the nominal under certain operating conditions - the previous load of the transformer, the temperature of the cooling medium.
   3.2.1.8. Allowable systematic and emergency overloads must be established:
   for oil transformers with a capacity up to 100 MVA · A inclusive - in accordance with GOST 14209, unless otherwise specified in the standards or technical conditions for specific groups or types of transformers;
   for transformers with a capacity exceeding 100 MVA · A - in the operating instructions;
   for dry transformers and transformers with a non-combustible liquid dielectric - in standards or technical conditions for specific groups or types of transformers.
Note. All elements of the transformer, including component parts, must meet these requirements.

(Changed edition, Amendment No. 4).

3.2.2. Requirements for dielectric strength of insulation
   3.2.2.1. Requirements for electrical insulation strength of transformers of voltage classes 3-500 kV - according to GOST 1516.1; transformers of voltage class 750 kV - according to GOST 20690. The requirements for electrical insulation strength of transformers of voltage class 1150 kV should be specified in the technical specifications for these transformers. In this case, the test voltage insulation of oil transformers must comply with the norms adopted for electrical equipment with normal insulation; the test voltages of dry transformers and transformers with a non-combustible liquid dielectric must not be lower than the norms adopted for electrical equipment with lightweight insulation.
   Notes:
   1. According to the agreement between the manufacturer and the consumer, in case of application of surge arresters, it is allowed to manufacture transformers for reduced test voltages in comparison with the requirements specified.
   2. Test insulation of the elements of control, interlocking and signaling circuits, as well as the circuits themselves for transformers sent from the manufacturer without their installation, not conduct.

3.2.2.2. For transformers designed to work at altitudes exceeding 1000 m (but not more than 3,500 m) above sea level, the external insulation must be calculated in accordance with GOST 1516.1:
   at installation height from 1000 to 2400 m inclusive - according to the norms for the installation height of 2400 m;
   at installation height from 2400 to 3500 m inclusive - according to the norms for the installation height of 3500 m.

3.2.2.1, 3.2.2.2. (Changed edition, Amendment No. 1).

3.3. Requirements for resistance to external influences
   3.3.1. Requirements for the resistance of transformers in case of short circuits
   3.3.1.1. Transformers must withstand external short-circuits in operation (test in accordance with GOST 20243) on any branch winding for any combination of supply sides corresponding to the operating modes of the transformer specified in the standards or technical specifications for this transformer, with the short-circuit current and its duration indicated below.
   3.3.1.2. The highest steady-state short-circuit current in two-winding regimes is determined as follows:
   for single-phase transformers and autotransformers connected between phase and neutral according to the formula
, (1)
   Where Ito.   - the highest steady-state short-circuit current of the branch, kA;
Unominee   - rated tapping voltage (phase), kV;
zyear   - short-circuit resistance, referred to the winding (side) and branch, ohm;
zfrom   - short circuit resistance of the network, Ohm;
   for three-phase transformers according to the formula
, (2)
   Where Ito.   - the highest steady-state linear short-circuit current of the branch, kA;
Unominee   - The nominal line voltage of the branch, kV.
   The highest steady-state short-circuit current in three-winding regimes is determined by a three-beam replacement scheme, each beam of which consists of the short-circuit resistance introduced by the transformer and the short-circuit impedance of the corresponding network z.

(Changed edition, Amendment No. 4).

3.3.1.3. Short-circuit resistance of the transformer zt.v., Om, are determined by the formula
, (3)
  Where Uto.   - design value of the short-circuit voltage of the tapping, reduced to the rated power of the transformer at the main branch,%;
Snom   - rated power of the transformer at the main branch, MV · A.
  When testing, it is allowed to take the measured short-circuit resistance value of the transformer.
  3.3.1.4. Short Circuit Resistance zfrom, Om, are determined by the formula
, (4)
  Where Uwith.   - rated line line voltage, kV;
Sc   - network short-circuit power, MV · A.
  Notes:
  1. For transformers with a power less than 1 MVA (for transformers with a power less than 3.15 MVA, developed after 01.01.91), the short-circuit impedance of the network is not taken into account (in formulas (1) and (2) zc = 0), if it is not more than 5% of the short-circuit resistance of the transformer.
  2. For transformers of voltage classes up to 35 kV inclusive. own needs of power plants, the short-circuit resistance of the network is not taken into account.

(Changed edition, Amendment No. 4).

3.3.1.5. The power of the three-phase short-circuit of the network should be taken from Table. 14.

Table 14

Note. In agreement with the consumer, it is allowed to take the short-circuit power of the network, which differ from the ones indicated in the table.

For three-winding autotransformers, the short-circuit power of the network on the LV side is:
   600 MVA - for a network with a nominal voltage of NN up to 20 kV and a power of autotransformers up to 63 MVA, inclusive;
   1000 MVA - for a network with a nominal voltage of 20 kV and above autotransformers of 220 kV;
   2000 MV · A - for windings of three-winding autotransformers of voltage classes 330, 500 and 750 kV.
   For three-winding autotransformers of voltage class 1150 kV, the short-circuit power is taken according to technical specifications for these transformers.

3.3.1.6. For three-winding transformers, excluding autotransformers, in any two- or three-winding mode, the multiplicity of the longest steady-state short-circuit current, determined in accordance with paragraph 3.3.1.2, with respect to the rated current of the winding should be limited in accordance with Table. 15 provided that the capacities of all the windings are equal. In the case of different winding capacities, the limiting multiplicities of the highest steady-state short-circuit current must be established in standards or technical conditions for such transformers.

Table 15

(Changed edition, Amendment No. 4).

3.3.1.7. (Excluded, Amendment No. 4).
   3.3.1.8. The greatest shock current of short circuit Iud, kA, is determined by the formula
, (5)
   Where Ito.   - the highest steady-state short-circuit current, kA;
  - coefficient, determined from Table. 17.

Table 17 *

_____________
   * Table. 16. (Excluded, Amend No. 4).

Note. For intermediate values ​​from 1 to 14, not specified in the table, the coefficient is allowed to be determined by linear interpolation.
   Designation: Up, Ua   - reactive and active components of the short-circuit voltage of the transformer, respectively.

(Changed edition, Amendment No. 4).

3.3.1.9. The maximum duration of a short circuit ( tk. max) at the terminals of transformers are taken with a short circuit on the sides with a rated voltage of 35 kV and below - 4 s, with a short circuit on the sides with a rated voltage of 110 kV and above - 3 seconds.
   3.3.1.10. Allowable duration of external short circuit tk, s, when the short-circuit current is less than the maximum steady-state one is determined by the formula
, (6)
   Where tk. max   - the permissible duration of a short circuit during the occurrence of the highest steady-state short-circuit current according to paragraph 3.3.1.9, c;
Ito.   - the highest steady-state short-circuit current, A;
Ito   - The steady-state short-circuit current is less than the highest steady-state, A.
   The maximum permissible duration of an external short circuit tto   is 15 seconds.
   3.3.2. Requirements for the resistance of transformers to impact shocks
   3.3.2.1. Oil transformers and transformers with a non-combustible liquid dielectric, other than those specified in 3.3.2.4, shall be able to withstand shock shocks in operation. In this case, the ratio of the current value to the nominal value (multiplicity) should not exceed the values ​​indicated in Table. 18.

Table 18.

Note. The permissibility of impact shocks by the current indicated in Table. 18, is provided by tests for short-circuit resistance in accordance with Sec. 6. For transformers with a power of more than 100 MVA, systematic shock shocks with a current of more than rated current must be agreed between the consumer and the manufacturer.

(Changed edition, Amendment No. 1).

3.3.2.2. For dry transformers, the permissible impact shocks are set in the standards or technical conditions for specific groups and types of dry transformers.
   3.3.2.3. With the number of shocks with a current of more than 100 per day, or with a duration of more than 15 s, a computational check of the load capacity should be carried out according to the manufacturer's method agreed with the consumer.
   3.3.2.4. Oil transformers of auxiliary needs of power plants must be able to withstand, during operation, impact shocks with a current of no more than 15 seconds each. In this case, the ratio of the current value to the nominal value (multiplicity) should not exceed the values ​​indicated in Table. 19.

Table 19

3.4. Reliability requirements
   For power transformers, the following reliability indicators are established:
   established reliable uptime - at least 25,000 hours;
   the probability of failure-free operation for an operating time of 8800 hours is not less than 0.995;
   service life to the first major overhaul - not less than 12 years;
   full service life - at least 25 years.

(Changed edition, Amendment No. 1).

3.5. Requirements for components
   3.5.1. Inputs of voltage classes 110-750 kV, installed on transformers, must be hermetic execution in accordance with GOST 10693 and GOST 23865.
   3.5.2. The clamps of dry transformers must be made in accordance with the requirements of GOST 10434.
   3.5.3. In two-winding transformers with a capacity of 32 MVA and more, three-winding autotransformers with a capacity of 63 MVA and more and transformers for the needs of power plants with a capacity of 10 MVA and more, it shall be possible to connect shielded current leads of LV inputs to the transformer tank or current transformer installations. In transformers of auxiliary needs of power stations of voltage classes up to 35 kV inclusive with a capacity of 10 MVA and more, additionally it shall be possible to connect shielded current leads of VN inputs to the transformer tank or current transformer installations.
   For these transformers, developed after 01.01.87, the main connecting dimensions for the inputs must be coordinated with the consumer.

(Changed edition, Amendment No. 1).

The specified capacity limits can be specified in standards or technical conditions for specific groups and types of transformers.
   3.5.4. Upon agreement between the manufacturer and the consumer, it shall be possible to secure the shielded current leads according to paragraph 3.5.3 to the cover or top of the transformer tank.
   3.5.5. In transformers with a capacity of 25 kVA and more voltage classes up to 330 kV inclusive, the design of the bushings and transformers must allow for the dismantling and installation of the input (or its external insulator) without removing the lid or the upper part of the tank, extracting the active part from the tank and draining the oil below the pressing rings .
   Note. The requirements of clause 3.5.5 do not apply to transformers for KTP.

3.5.6. By order of the consumer, the transformers are manufactured with inputs for II, IV pollution levels according to GOST 9920.

(Changed edition, Amendment No. 4).

3.5.7. Upon agreement between the consumer and the manufacturer, transformers of voltage classes of 35 kV and higher are manufactured with cable entries.
   3.5.8. Upon agreement between the consumer and the manufacturer, transformers of voltage classes of 110 kV and higher are manufactured with inputs for connection to gas-insulated equipment.
3.5.9. The location of the inputs of oil transformers and transformers with a non-flammable liquid dielectric and clamps of dry transformers should be specified in standards or technical conditions for transformers of specific groups and types.
   3.5.10. The on-load tap-changers must comply with the requirements of GOST 24126 or technical specifications for on-load tap-changers that are compatible with the consumer.

(Changed edition, Amendment No. 1).

3.5.11. Oil transformers should be equipped with built-in current transformers in accordance with GOST 7746 in accordance with the requirements of standards or technical conditions for transformers of specific groups and types.
   3.5.12. All branches from the current transformers must be disconnected to allow the cables to be connected. Cables must be placed in the terminal box to use one branch.

(Changed edition, Amendment No. 1).

3.5.13. The capacity of the expander must ensure the constant presence of oil in it under all operating conditions of the transformer from the de-energized state to the rated load and with variations in the ambient air temperature specified in clauses 1.2 or 1.3, and with the overloads established in Sec. 3, the oil should not pour out.
   The oil indicator or expander must be marked with reference marks for the following oil temperatures:
   minus 45, 15, 40 ° C - for climatic modification of U;
   minus 60, 15, 40 ° C - for climatic modifications of CL, UHL.
   Note. For specific conditions of the cooling medium, which differ from the limiting ones specified in subparagraphs 1.2 or 1.3 (internal installation, etc.) the capacity of the expander is selected based on the temperature limits normalized for these specific conditions.

(Changed edition, Amendment No. 4).

3.5.14. Oil transformers and transformers with a non-combustible liquid dielectric with a capacity of 25 kVA or more must be equipped with an expander or other protection that protects the oil or non-flammable liquid dielectric in the tank from direct contact with the surrounding air.
   The expander must be equipped with an air drier with an oil seal or other device to protect the oil or other non-flammable liquid dielectric in the expander from direct contact with the surrounding air.
   The design of the air dryer should provide the possibility of monitoring the state of the sorbent during operation of the transformer.

(Changed edition, Amendment No. 1).

3.5.15. The expander design should exclude the possibility of oil residues from the expander entering the tank.
   3.5.16. At the bottom of the expander there must be a stopper for draining the oil.
   In transformers with a gas relay, a locking device with a position indicator must be installed between the expander and the tank.

(Changed edition, Amendment No. 4).

3.5.17. In transformers with a capacity of up to 1 MVA, the expander must be equipped with an oil filling device, and in transformers of higher power, with a shut-off device.
   3.5.18. Tanks of oil transformers and transformers with a non-combustible liquid dielectric must withstand the tests for mechanical strength in accordance with Table. 20 and item 3.5.19. Tests of transformers with a capacity of up to 6.3 MVA. for voltage up to 35 kV inclusive. and with corrugated tanks - according to the standards or technical conditions for these transformers.
   Table 20

(Changed edition, Amendment No. 4).

3.5.19. Tanks of transformers with nitrogen blanket without expander must withstand the tests for mechanical strength under vacuum according to the norms indicated in Table. 20, at an overpressure of 75 + 5 kPa.
   3.5.20. In transformers with an active part mass of more than 25 grams, the tanks must have a bottom connector.
   3.5.21. By agreement between the manufacturer and the consumer, the transformer tanks can be made of an all-in-one design (with a welded connector).
   3.5.22. Oil transformers and transformers with a non-combustible liquid dielectric, except sealed with a corrugated tank, must be equipped with an oil indicator (liquid level indicator).
3.5.23. In transformers with a capacity of 10 MVA and more, the oil indicator should be of the switch type and include sensors for minimum and maximum oil levels.
   3.5.24. The design of the oil indicator with a glass tube should ensure the replacement of the tube without draining the oil from the expander.
   3.5.25. Oil transformers with a capacity of 1 MVA and more, as well as hermetically sealed oil transformers, except transformers with corrugated tanks, and transformers with a non-combustible liquid dielectric with a capacity of 160 kVA and more must have a thermometer with two adjustable signal contacts.
   Oil transformers and transformers with a non-combustible liquid dielectric of all types of cooling systems, except types M and H, should be equipped with manometric thermometers for measuring the temperature of the upper oil layers and for automatic control of the cooling system.
   The temperature error of manometric thermometers should not exceed ± 5 ° С.

(Changed edition, Amendment No. 1).

3.5.26. Signal contacts of manometric thermometers should work in control and monitoring circuits with a voltage of 220 V DC or AC.
   3.5.27. The body of the manometric thermometer should be reinforced at a height of not more than 1.6 m from the foundation level.
   3.5.28. Oil transformers and transformers with a non-flammable liquid dielectric must be equipped with fittings for pouring, sampling, draining and filtering oil or a non-flammable liquid dielectric and connecting the vacuum pump in accordance with the requirements of standards or technical conditions for specific groups or types of transformers.
   3.5.29. Sealed transformers without expanders must be equipped with a manometer.
   Sealed transformers with corrugated tanks must be equipped with a vacuum gauge according to the customer's order.
   3.5.30. In transformers with a voltage of 110 kV and above, the oil sampling arm must be in the lower part of the tank and the on-load tap-changer tank and must:
   allow to take an oil sample at a height of no more than 10 mm from the bottom of the tank;
   allow the possibility of attaching a rubber hose and a smooth control of the jet.
   For other transformers, the requirements for the oil sampling arm are in accordance with the standards or specifications for specific groups or types of transformers.
   3.5.31. A transformer whose radiators or coolers are dismantled for the time of transportation must have a shut-off valve that allows the radiators or coolers to be removed without draining the tank.
   3.5.32. Radiators and coolers dismantled for the time of transportation should be provided with stoppers in the lower and upper parts.
   3.5.33. Cranes and gates installed on the transformer must have marks indicating their position.
   3.5.34. The shut-off valve must be removable.
   3.5.35. Shut-off valves of transformers with the types of cooling systems DC, NDC, C, NC should provide vacuuming of the tank, cooling system and its individual elements.
   3.5.36. Oil transformers with a capacity of 1.6 MVA and more with an expander must be equipped with a gas relay. Transformers with a capacity of 0,4-1 МВ · А with the expander are supplied with a gas relay at the request of the consumer.
   The relay must be adapted for visual control of the evolved gas, as well as for sampling the gas.

(Changed edition, Amendment No. 4).

3.5.37. The expander of the on-load tap-changer must be equipped with a jet protective relay and an element indicating a low oil level.
   3.5.38. By order of the customer, transformers with a capacity of 400 and 630 kVA with an expander designed to supply auxiliary power to stations and substations for installation inside buildings must be equipped with a gas relay.
   3.5.39. In transformers with a gas relay, the cavities in which gases can accumulate must be connected to a manifold that removes gas into the gas relay.
   3.5.40. The installation of a gas relay on the transformer must ensure that there are no false alarms when the transformer is operating.
3.5.41. Transformers, except sealed transformers with corrugated tanks, shall be equipped with devices to protect the tank from damage when the internal pressure rises in accordance with the requirements of GOST 12.2.007.2.
   3.5.42. Transformers with a capacity of 1 MVA and more, hermetic transformers for complete transformer substations with a capacity of 160 kVA and more with a manovacuum meter, as well as transformers specified in 3.5.38, shall be equipped with a terminal box and wiring in a protective enclosure connecting devices alarm, protection, as well as built-in current transformers with terminal box.

(Changed edition, Amendments No. 1, 3).

3.5.43. Transformers with a capacity of 125 MVA and more must be equipped with a device for sampling gas from the gas relay from the level of installation of the transformer.

(Changed edition, Amendment No. 1).

3.5.44. Transformers with the capacity of 63 MVA and more must provide for the possibility of installing thermal detectors for a fire detection device.
   3.5.45. Transformers with an LV winding voltage of 0.69 kV or less shall be fitted with a break-through fuse at the customer's request.
   3.5.46. Transformers with a capacity of 1 MVA and more voltage classes of 6 kV and higher must be equipped with a device for rolling in the longitudinal and transverse directions.
   Dry transformers must be made on a sled, designed for both longitudinal and transverse movements.
   The way of movement of the remaining transformers and transformers for the KTP must be installed in standards or technical conditions for these transformers.
   3.5.47. The width of the track and the distance between the middle lines of the rollers for transformers weighing less than 200 tons shall be as indicated in Fig. 1 and in Table. 21, and for transformers of 200 tons or more - in Fig. 2-4 and in Table. 22.

Transformers weighing less than 200 g

Table 21

Notes:
   1. Application of a specific type of roller with a flange or smooth rollers, as well as those indicated in Table. 21, 22 and in Fig. 1-4 distances between rollers should be installed in standards or technical conditions for transformers of specific groups and types.
   2. The connection between the mass of the transformers and the track is recommended.
   3. Relationship between dimensions in Fig. 2-4 and the seats of the carriages on the transformer must correspond to the dimensions of the rails in accordance with GOST 7174.
   4. By agreement between the manufacturer and the user, the use of track widths for transverse rolling of transformers, as well as the number of rollers, other than those indicated in Fig. 2-4.

Transformers with a mass of 200-255 tons

Transformers with a mass of 255-300 tons

Table 22

(Changed edition, Amendment No. 4).

Transformers with a mass of 300-700 t



   Heck. 4

3.5.48. In transformers with a total mass of more than 0.05 tons, it shall be possible to move them during installation.
   Transformers with a total mass of more than 5 tons should have a device for broaching during rolling.
   Components of the transformer with a mass of more than 0.05 tons should have devices for slinging during lifting.
   3.5.49. Transformers with a total mass of more than 25 tons should be equipped with devices located in the lower part of the tank for stopping the jacks, which provide the installation of jacks, supplied for the transformer.
   3.5.50. Oil transformers and transformers with a non-combustible liquid dielectric must have hooks or other devices to lift a fully assembled and oil filled transformer.

3.5.51. (Excluded, Amend No. 1).

3.5.52. In oil transformers of voltage classes of 220 kV and above, the oil must be completely protected from contact with the surrounding air.
   3.5.53. The oil in the on-load tap-changer tank or expander must be protected from direct contact with the ambient air by an air-drying dryer with an oil seal or other device.

(Changed edition, Amendment No. 1).

3.5.54. Oil transformers with an oil mass of more than 1000 kg should be equipped with filters: thermosyphon - for types of cooling systems M and D, adsorptive - for other types of cooling systems and filters for oil purification from mechanical impurities - for types of cooling systems DC, NDC, Ц, НЦ.

(Changed edition, Amendment No. 4).

3.6. Requirements for cooling systems for oil transformers
   3.6.1. General requirements for construction
   3.6.1.1. The cooling system should be designed to remove the heat generated in the transformer into the cooling medium and ensure its thermal regime in accordance with the requirements of paragraph 3.2.1.
   3.6.1.2. With the exception of hermetic transformers with corrugated tanks, the cooling system must be mounted on the tank or removed.

(Changed edition, Amendment No. 4).

3.6.1.3. Cooling systems of types D, DC, NDC, C and NC should have automatic control cabinets.
   Cabinets for automatic control of cooling systems of DC, NDC, C and NC types should be installed separately from the transformer tank.
   3.6.1.4. Cooling systems for DC, NDC, C and NC types should include reserve coolers.

3.6.1.5. (Excluded, Amendment No. 4).

3.6.1.6. Fan motors and electric pumps must have circuit breakers to protect against short circuit currents. In this case, the electric motors of the cooling systems of the DC, NDC, C, and NC types should have protection against operation in two phases.
   3.6.1.7. The supply voltage of electric motors of fans and electric pumps is 380 V AC, control circuits - 220 V DC or AC.
   On the order of the consumer in the cooling system of the type D transformers of the voltage class 110 kV or less, electric motors with a voltage of 220 V AC can be used.

3.6.1.8. (Excluded, Amendment No. 4).

3.6.1.9. Cooling systems of NDC and NC types should be provided with devices for connecting oil consumption monitoring devices.

3.6.1.10. (Excluded, Amendment No. 4).

3.6.1.11. Coolers of the removed cooling systems of types Ц and НЦ should be established in premises with air temperature not less than 5 ° С.
   3.6.1.12. In cooling systems of types C and NC, the hydrostatic pressure of the oil above the water pressure (at any point of the coolant) must be exceeded by at least 10 kPa with the minimum oil level in the transformer expander.
   3.6.1.13. In cooling systems of types C and N, each electric pump must be equipped with a pressure gauge and each cooler with manometers and thermometers to measure the pressure and temperature of the oil and water at the inlet and outlet connections of the cooler.
   3.6.2. Requirements for the functioning of the cooling system type D
   3.6.2.1. Automatic control of the cooling system of type D should provide:
   the activation of the electric motors of the fans when the temperature of the upper layers of the oil reaches 55 ° C or when a current equal to 1.05 nominal is reached, regardless of the temperature of the upper oil layers;
   switching off the fan motors when the temperature of the upper oil layers drops to 50 ° C, if the load current is less than 1.05 nominal.
   3.6.3. Requirements for the functioning of cooling systems of DC, NDC, C, NC types
   3.6.3.1. Automatic control of cooling systems of DC, NDC, C and NC types should ensure:
   inclusion of electric pumps and electric motors of fans (for cooling systems of DC and NDC types);
   the inclusion of electric pumps and fan motors (for cooling systems of DC and NDC types) of the backup cooler in exchange for any automatically disconnected worker;
   the inclusion of backup power in case of inadmissible decrease or disappearance of voltage in the main circuit, as well as reverse switching to the main circuit while restoring the permissible voltage in it;
   switching on and off heaters of the automatic control cabinet for cooling systems of the DC and NDC types.

(Changed edition, Amendment No. 1).

3.6.3.2. Automatic control of cooling systems of NDC, C, NC types should provide the following work of electric pumps:
   at the temperature of the upper oil layers in the tank equal to 15 ° C or more, all working electric pumps must work;
At the temperature of the upper oil layers in the tank less than 15 ° C, only the starting electric pump should work.
   3.6.3.3. Automatic control of cooling systems of DC and NDC types should ensure the operation of electric motors of fans and electric pumps for the cooling system of the type of DC and fan motors for the cooling system of the NDC type in the following groups:
   the first - in the idle mode or at a load of not more than 40% of the rated current;
   the first and second - with the load of the transformer more than 40% of the rated current;
   first, second and third - with a transformer load of more than 75% of the rated current.
   With a small number of coolers, the number of groups can be reduced.
   Fan motors should only work at the temperature of the upper oil layers in the tank over 40 ° C in groups, depending on the load of the transformer.

(Changed edition, Amendment No. 4).

3.6.3.4. In cooling systems of types C and N, the circulation of water through the oil coolers should be automatically carried out after switching on the working electric oil circulation pumps and turn off when the temperature of the upper oil layers in the tank drops below 15 ° C or when the voltage is removed.
   3.6.3.5. Automatic control of cooling systems of DC, NDC, C, and NC types should provide the signals for the following signaling:
   a) on the inclusion of a cooling system:
   when starting the electric pump;
   when the working electric pumps are switched on;
   b) about the malfunction of the cooling system:
   emergency shutdown of the starting electric pump;
   at emergency disconnection of any working electropump;
   emergency shutdown of the backup electric pump;
   when the backup electric pump is switched on;
   when the starting electric pump is not switched on while the working electric pumps are running;
   when the backup power source of the cooling system is switched on;
   c) to turn off the cooling system:
   when the working and backup power sources of the cooling system are disconnected;
   at switching-off of starting and all working electropumps;
   d) on switching on and off the heater (for cooling systems of DC and NDC types).
   3.6.4. Notes on the operation of transformers when the cooling system is interrupted should be stated in the operating documentation.
   3.6.5. Introductory devices for protection against short-circuit currents of cabinets for automatic control of the cooling system must be resistant to the effect of short-circuit currents with an amplitude current value of 16 kA.

3.6.6. (Excluded, Amend No. 1).

3.6.7. Cooling systems must allow manual control.
   3.7. Requirements for protective coatings
   3.7.1. For oil transformers, the metal surfaces of the active part elements, the inner surfaces of the tank, the expander and the protective device (exhaust pipe) must have an oil resistant coating protecting the oil from contact with them and not adversely affecting the oil.
   It is allowed not to protect the end surfaces of the magnetic system, magnetic screens, aluminum tires, parts of switching devices, fasteners, as well as other parts and components of the active part that do not have an active catalytic effect on the oil.
   3.7.2. Chillers of cooling systems must be cleaned and rinsed with transformer oil.
   Pipes of oil lines of cooling systems connecting the transformer tank with coolers should be corrosion-resistant and oil resistant or have corrosion-resistant and oil-resistant internal coating.

(Changed edition, Change No. 1, 4).

3.7.3. For transformers with a non-flammable liquid dielectric and oil transformers with corrugated tanks, the requirements for the protection of internal surfaces must be specified in the standards or technical conditions for these transformers.
   3.7.4. The outer surfaces of the transformer of non-corrosive materials must have weatherproof coatings. The paint and varnish coatings used for this purpose must be gray, light gray or dark gray.
For dry transformers, the requirements for the color of coatings on external surfaces must be specified in the technical conditions for these transformers.
   Surfaces of threaded joints, joints of a tank with an articulated conveyor, skating surfaces of skating rinks, grounding surfaces are allowed not to be protected by coatings. In this case, these surfaces are subject to conservation.

(Changed edition, Change No. 1, 4).

3.7.5. Transformers for KTP with the capacity of St. 250 kV · A and KRU must be painted in the same color as their cabinets.

(Changed edition, Change No. 3).

3.8. Grounding Requirements
   3.8.1. The earthing of the transformer tanks must be carried out in accordance with the requirements of GOST 12.2.007.0 with the following additions:
   when used for grounding a threaded connection, the thread diameter shall be M12 for transformers with a capacity of 25 kVA and more and M8 for transformers with a power of less than 25 kVA;
   the surface of the grounding contact must be sufficient to connect a steel bar section of at least 40 x 4 mm;
   the earthing contact must be located in an accessible location at the bottom of the tank on the LV side, and in transformers with cooling type C - in an accessible location of the core.
   3.8.2. The magnetic system of the transformer and the massive metal components must have a reliable metallic connection to the tank.
   3.9. Load and external mechanical stress requirements
   3.9.1. For dry transformers with insulation classes of heat resistance F, H, C according to GOST 8865, designed to operate at an altitude exceeding 1000 m (but not more than 3500 m) above sea level, the rated power should be reduced depending on the height of the installation and specified in standards or technical conditions for these transformers.
   For other transformers designed to operate at altitudes exceeding 1000 m (but not more than 3,500 m) above sea level, the rated power must be maintained regardless of the height of the installation.
   3.9.2. The power of the windings at all branches must be nominal, except for the negative branches of the windings below minus 5% of the rated voltage.
   When operating at branches below minus 5% of the rated voltage, the winding power must correspond to a current that is equal to the rated tapping current minus 5%, and in the absence of such a tap, to the nearest larger current (for example, at a range of ± 8 x 1.5% - the rated tapping current minus 4 x 1.5%).
   3.9.3. Oil transformers and transformers with a non-combustible liquid dielectric must be designed for the following long-term operation modes.
   3.9.3.1. For all transformers - for a continuous load of one or two windings with a current exceeding by 5% the rated branch current, to which the corresponding winding is included, if the voltage on either winding does not exceed the nominal voltage of the corresponding branch. At the same time, the load current should not exceed 1.05 of the rated winding current, in the autotransformer the current in the common winding should not exceed the longest permissible current of this winding, and the power of the transformer should not be more than nominal.
   3.9.3.2. For a three-winding transformer, any distribution of continuous loads along its windings, provided that none of the three windings is loaded with a current that exceeds the permissible value in accordance with paragraph 3.9.3.1, and the transformer's losses do not exceed the sum of its idling loss and the largest of the losses of a short windings of windings.
   3.9.3.3. For a three-winding autotransformer, any distribution of continuous loads along its windings, provided that none of the three windings is loaded with a current exceeding the permissible value in accordance with paragraph 3.9.3.1., And the losses of the autotransformer will not exceed the sum of its idling losses and maximum load losses.
Note. For a winding loaded with a current exceeding its rated current, as well as for the upper layers of the oil or other liquid dielectric and for other windings, the calculated temperature rise may be higher than specified in this section, but not more than 5 ° C. This also applies to the calculated temperature elevations corrected by the results of the heating tests.

3.9.4. Permissible continuous loads of dry transformers must be installed in standards or technical conditions for transformers of specific groups and types.
   3.9.5. In transformers with a HN winding split into two parts, the nominal power of each of its parts must be equal to 50% of the rated power of the transformer.
   3.9.6. The inputs and outlets of the neutral of the winding of the LV must be selected for a continuous load with the current equal to:
   for transformers with a winding connection scheme U / Un - 25%, for transformers with winding connection schemes U / Zn and D / Un - 75% of the rated current of the winding HH.
   3.9.7. Inputs and outlets of VN neutral of transformers of voltage classes 6 - 35 kV with a circuit for connecting Un / D windings of all transformers of voltage classes of 110 kV and higher must be selected for a continuous load with a current equal to the rated current of the VN winding.
   Inputs and outlets of the neutral of the MV triple-winding transformers of voltage classes of 110 kV and higher should be selected for a continuous load with a current equal to the rated current of the winding HV.

(Changed edition, Amendment No. 1).

3.9.8. The shape of the voltage curve applied to the transformer must be practically sinusoidal, and the system of phase voltages is practically symmetrical.
   Note. The concepts "almost sinusoidal" and "practically symmetrical" - according to GOST 3484.1-GOST 3484.5.

3.9.9. (Excluded, Amendment No. 4).

3.9.10. Layout categories for oil transformers, transformers with a non-flammable liquid dielectric and dry sealed transformers - 1 - 4, for dry leaky transformers - 3, 4 according to GOST 15150.