This document is Part 11 of GB/T 1094 Power Transformers. The following parts of GB/T 1094 have been issued:
— Part 1: General;
— Part 2: Temperature Rise for Liquid-immersed Transformers;
— Part 3: Insulation Levels, Dielectric Tests and External Clearances in Air;
— Part 4: Guide to the Lightning Impulse and Switching Impulse Testing — Power Transformers and Reactors;
— Part 5: Ability to Withstand Short Circuit;
— Part 6: Reactors;
— Part 7: Loading Guide for Oil-immersed Power Transformers;
— Part 10: Determination of Sound Levels;
— Part 10.1: Determination of Sound Levels—Application Guide;
— Part 11: Dry-type Transformers;
— Part 12: Loading Guide for Dry-type Power Transformers;
— Part 14: Liquid-immersed Power Transformer Using High-temperature Insulation Materials;
— Part 15: Gas-filled Power Transformers;
— Part 16: Transformers for Wind Turbine Applications;
— Part 18: Measurement of Frequency Response;
— Part 23: DC Magnetic Bias Suppression Devices.
This document replaces GB/T 1094.11-2007 Power Transformers — Part 11: Dry-type Transformers.
Power Transformers — Part 11: Dry-type Transformers
1 Scope
This document specifies the terms and definitions, service conditions, ratings and general requirements, tappings, connections, ability to withstand short circuit, rating plate, temperature-rise limits, insulation levels, climatic, environmental and fire behaviour classes, seismic performance, tests, tolerances, protection against direct contact, degrees of protection provided by enclosures, earthing terminal, information required with enquiry and order, and installation and safety of dry-type transformers.
This document is applicable to dry-type power transformers (including auto-transformers, hereinafter referred to as “transformers”) having values of highest voltage for equipment up to and including 72.5 kV and at least one winding operating at greater than 1.1 kV.
This document is not applicable to:
— gas-filled dry-type transformers (where the gas is not air);
— single-phase transformers rated at less than 5 kVA;
— polyphase transformers rated at less than 15 kVA;
— instrument transformers;
— starting transformers;
— testing transformers;
— traction transformers mounted on rolling stock;
— flameproof and mining transformers;
— welding transformers;
— voltage regulating transformers;
— small power transformers in which safety is a special consideration.
Where standards do not exist for the transformers mentioned above or for other special transformers, this document may be applicable as a whole or in parts.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 311.1 Insulation Co-ordination — Part 1: Definitions, Principles and Rules (GB/T 311.1-2012, IEC 60071-1:2006, MOD)
GB/T 311.2 Insulation Co-ordination — Part 2: Application Guide (GB/T 311.2-2013, IEC 60071-2:1996, MOD)
GB/T 1094.1-2013 Power Transformers — Part 1: General (eqv IEC 60076-1:2011, MOD)
GB/T 1094.2 Power Transformers — Part 2: Temperature Rise for Liquid-immersed Transformers (GB/T 1094.2-2013, IEC 60076-2:2011, MOD)
GB/T 1094.3-2017 Power Transformers — Part 3: Insulation Levels, Dielectric Tests and External Clearances in Air (IEC 60076-3:2013, MOD)
GB/T 1094.5 Power Transformers — Part 5: Ability to Withstand Short Circuit (GB/T 1094.5-2008, IEC 60076-5:2006, MOD)
GB/T 1094.10 Power Transformers — Part 10: Determination of Sound Levels (GB/T 1094.10-2003, IEC 60076-10:2001, MOD)
GB/T 1094.12-2013 Power Transformers — Part 12: Loading Guide for Oil-immersed Power Transformers (IEC 60076-12:2008, MOD)
GB/T 2424.25 Environmental Testing for Electric and Electronic Products — Part 3: Test Guidance — Seismic Test Methods (GB/T 2424.25-2000, IEC 60068-3-3:1991)
GB/T 2900.95 Electrotechnical Terminology — Transformers, Voltage Regulators and Reactors (GB/T 2900.2900.95-2015, IEC 60050-421:1990, NEQ)
GB/T 4208 Degrees of Protection Provided by Enclosure (IP Code) (GB/T 4208-2017, IEC 60529:2013, IDT)
GB/T 4797.7-2008 Classification of Environmental Conditions — Environmental Conditions of Nature — Earthquake Vibration and Shock (IEC 60721-2-6:1990, IDT)
GB/T 4798.4 Environmental Conditions Existing in the Application of Electric and Electronic Products — Section 4: Stationary Use at Non-weather-protected Locations (GB/T 4798.4-2007, IEC 60721-3-4:1995 and Amd 1:1996, MOD)
GB/T 7354 High-voltage Test Techniques — Partial Discharge Measurements (GB/T 7354-2018, IEC 60270:2000, MOD)
GB/T 11021 Electrical Insulation — Thermal Evaluation and Designation (GB/T 11021-2014, IEC 60085:2007, IDT)
GB/T 17467 High-voltage/Low-voltage Prefabricated Substation (GB/T 17467-2020, IEC 62271-202:2014, MOD)
GB/T 18380.31 Tests on Electric and Optical Fibre Cables under Fire Conditions — Part 31: Test for Certical Flame Spread of Vertically-mounted Bunched Wires or Cables — Apparatus (GB/T 18380.31-2008, IEC 60332-3-10:2000, IDT)
GB/T 18494.1 Converter Transformers — Part 1: Transformers for Industrial Applications (GB/T 18494.1-2014, IE C61378-1:2011, MOD)
GB/T 26218.1 Selection and Dimensioning of High-voltage Insulators Intended for Use in Polluted Conditions — Part 1: Definitions, Information and General Principles (GB/T 26218.1-2010, IEC/TS 60815-1:2008, MOD)
GB/T 30790.6 Paints and Varnishes — Corrosion Protection of Steel Structures by Protective Paint Systems — Part 6: Laboratory Performance Test Methods (GB/T 30790.6-2014, ISO 12944-6:1998, MOD)
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.95 and the following apply.
3.1
dry-type transformer
transformer of which the magnetic circuit and windings are not immersed in an insulating liquid
3.2
totally enclosed dry-type transformer
transformer in an un-pressurised enclosure cooled by the circulation of the internal air having no intentional exchange with external air
3.3
enclosed dry-type transformer
transformer in a ventilated enclosure cooled by the circulation of the external air
Foreword III
Introduction VII
1 Scope
2 Normative References
3 Terms and Definitions
4 Service Conditions
5 Rating and General Requirements
6 Tappings
7 Connections
8 Ability to withstand short circuit
9 Rating Plate
10 Temperature-rise Limits
11 Insulation Level
12 Climatic, Environmental and Fire Behaviour Classes
13 Seismic Performance
14 Test
15 Tolerances
16 Protection against Direct Contact
17 Degrees of Protection Provided by Enclosures
18 Earthing Terminal
19 Information Required with Enquiry and Order
20 Installation and Safety
Annex A (Informative) Structural Changes between This Document and ISO 60076-11:2018
Annex B (Informative) Technical Deviations between This Document and IEC 60076-11:2018 and Their Justifications
Annex C (Nominative) Cooling of Transformer in Naturally Ventilated Room
Annex D (Nominative) Environmental Test for Evaluation of Outdoor Transformers without Enclosure
Annex E (Nominative) Seismic Performance and Seismic Test
Annex F (Nominative) Calculation of the Losses with Different Reference Temperatures and/or Winding Material
Annex G (Informative) Installation and Safety of Dry-type Transformers
Bibliography
Figure 1 Basic measuring circuit for the partial discharge test for a single-phase transformer
Figure 2 Basic measuring circuit for the partial discharge test for a three-phase transformer
Figure 3 Voltage application for routine partial discharge test
Figure 4 Example of back-to-back method — Single phase
Figure 5 Example of back-to-back method — Three-phase
Figure 6 Voltage application for special partial discharge test
Figure 7 Test chamber
Figure 8 Test chamber details
Figure C.1 Heat dissipation in a natural ventilated room
Figure D.1 Salt fog multi-parameter ageing cycle
Table 1 Letter symbols
Table 2 Winding temperature-rise limits
Table 3 Insulation level
Table 4 Applied voltage level correction factor
Table 5 Sequence of tests
Table 6 Climatic class features
Table 7 Environmental classes
Table 8 Size and Mass of Test Package
Table A.1 Comparison of clause and subclause numbers between this standard and IEC 60076-11:2018
Table A.2 Comparison of figure/table numbers between this document and IEC 60076-11:2018
Table B.1 Technical deviations between this document and IEC 60076-11:2018 and their justifications
Table D.1 Outdoor environmental classes
Table E.1 Approximate acceleration level and performance level
Table E.2 Ground acceleration level (AG)
Table E.3 Recommended super elevation factors (K)
Table E.4 Direction factors (D)
