Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
In this part, Clause 2, Clause 3, 11.2~11.12, Clause 12, Clause 13, Annex A ~Annex F, Annex H and Annex I are recommendatory and the rest are mandatory.
GB 1094 consists of the following parts under the general title Power Transformers:
——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: Design and Application of Liquid-immersed Transformers Using High-temperature Insulation Material;
——Part 16: Wind Power Transformer.
This is part 1 of GB 1094.
This part is drafted in accordance with the rules given in the GB/T 1.1-2009.
This part supersedes GB 1094.1-1996 Power Transformers Part 1: General and has the main technical changes as follows compared with GB 1094.1-1996:
——Definition of harmonic content is added;
——Transport clause is added;
——Functional specification is added;
——Connection symbol of single-phase transformer is added;
——Safety and environmental requirements are added;
——The requirements of liquid preservation system are added;
——The clause on DC currents in neutral circuits is added;
——Test items are adjusted;
——Leak testing with pressure for liquid immersed transformers, vacuum deflection test for liquid immersed transformers, pressure deflection test for liquid immersed transformers and vacuum tightness test on site for liquid immersed transformers are added;
——Informative annexes on facilities for future fitting of condition monitoring systems to transformers and environmental and safety considerations are added.
This part is modified in relation to ISO 60076-1:2011 Power Transformers Part 1: General.
There are technical differences between this part and IEC 60076-1:2011,and the technical differences has been indicated by (｜) in the outer side page margin; see Annex A for list of technical differences and reasons.
The following editorial changes are made in this part:
——"Ei" and "Ii" in the keys of equation, in 3.13.3 of IEC 60076-1:2011 are changed to "E2i" and "I2i";
——Figure la), Figure 1b) and Figure 1c) in IEC 60076-1:2011 are combined into one figure;
——Information in "note" of 7.1.2 in IEC 60076-1:2011 is removed;
——Examples under 7.2.4 in IEC 60076-1:2011 are moved to 7.2.5;
——Structural form of Table 1 in IEC 60076-1:2011 is adjusted;
——Tap positions in Table B.2 and Table B.3 of IEC 60076-1:2011 are modified;
——Informative annex A is added, in which the technical differences between this part and IEC 60076-1:2011 and reasons are listed;
——Informative Annex B is added, in which the vacuum deflection test for liquid immersed transformers, pressure deflection test for liquid immersed transformers not included in IEC 60076-1:2011 are listed;
——Annex A, Annex B, Annex C, Annex D, Annex E, Annex F and Annex G in IEC 60076-1:2011 are renamed as Annex D, Annex E, Annex F, Annex C, Annex G, Annex H and Annex I.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. Issuing authority shall not be held responsible for identifying any or all such patent rights.
This part is proposed by the China Electrical Equipment Industry Association.
This part is under the jurisdiction of National Technical Committee on Transformer of Standardization Administration of China (SAC/TC 44).
Drafting organizations of this part: Shenyang Transformer Research Institute, State Grid Electric Power Research Institute, Baoding Tianwei Baobian Electric Co., Ltd., Sunten Electric Equipment Co., Ltd., TBEA Shenyang Transformer Co., Ltd., Xi'an XD Transformer Co., Ltd., Jilin Electric Power Research Institute, TBEA Hengyang Transformer Co., Ltd., Pearl Electric Co.,Ltd., Wujiang transformer Co., Ltd., Guangdong Julong Electric Power Equipment Co., Ltd., East China Grid Company Limited, China Electric Equipment (Jiangsu) Co., Ltd., Chint Electric Inc., Junfa Electric, Wolong Electric Yinchuan Transformer Co., Ltd.
Chief drafting staff of this part: Zhang Xianzhong, Zhang Zhongguo, Wu Zhirong, Hu Zhenzhong, Liu Yan, An Zhen, Qi Yingshi, Mi Chuanlong, Zhang Dong, Ao Ming, Sun Shubo, Cai Dingguo, Lin Canhua, Wang Wenguang, Jiang Yimin, Xu Zihong, Li Jinbiao, Fan Jianping, Lu Wei.
The previous editions of standard superseded by this part are listed as follows:
——GB 1094.1-1985, GB 1094.1-1996.
NATIONAL STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
中华人民共和国国家标准
GB 1094.1-2013
Power Transformers - Part 1: General
电力变压器 第1部分: 总则
1 Scope
This part of GB 1094 applies to three-phase and single-phase power transformers (including auto-transformers) with the exception of certain categories of small and special transformers such as:
——single-phase transformers with rated power less than 1 kVA and three-phase transformers less than 5 kVA;
——transformers, which have no windings with rated voltage higher than 1000 V;
——instrument transformers;
——traction transformers mounted on rolling stock;
——starting transformers;
——testing transformers;
——welding transformers;
——explosion-proof and mining transformers;
——transformers for deep water (submerged) applications.
When some standards do not exist for such categories of transformers (in particular transformer having no winding exceeding 1000V for industrial applications), this part may still be applicable either as a whole or in part.
This part does not address the requirements that would make a transformer suitable for mounting in a position accessible to the general public.
For those categories of power transformers and reactors which have their own standards, this part is applicable only to the extent in which it is specifically called up by cross-reference in the other standard. Such standards exist for:
——reactors (GB/T 1094.6);
——dry-type transformers (GB 1094.11);
——self-protected transformers (IEC 60076-13);
——gas-filled power transformers (IEC 60076-15);
——transformers for wind turbine applications (GB 1094.16);
——traction transformers and traction reactors (GB/T 25120);
——converter transformers for industrial applications (GB/T 18494.1);
——converter transformers for HVDC applications (GB/T 18494.2).
At several places in this part it is specified or recommended that an 'agreement' should be reached concerning alternative or additional technical solutions or procedures. Such agreement is made between the manufacturer and the purchaser. The matters should preferably be raised at an early stage and the agreements included in the contract specification.
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 1094.2 Power Transformers Part 2: Temperature Rise for Liquid-immersed Transformers (GB 1094.2-2013, IEC 60076 - 2: 2011, MOD)
GB 1094.3 Power transformers - Part 3: Insulation Levels, Dielectric Tests and External Clearances in Air (GB 1094.3-2003, IEC 60076-3: 2000, MOD)
GB 1094.5 Power Transformers - Part 5: Ability to Withstand Short Circuit (GB 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 1094.11 Power Transformers - Part 11: Dry-type Transformers (GB 1094.11-2007, IEC 60076-11: 2004, MOD)
GB/T 2521 Cold-rolled Grain-oriented and Non-oriented Magnetic steel Strip (Sheet) (GB/T 2521-2008, IEC 60404-8-7: 1998 and IEC60404-8-4: 1998, MOD)
GB 2536 Fluids for Electrotechnical Applications - Unused Mineral Insulating oils for Transformers and Switchgear(GB 2536-2011, IEC 60296: 2003, MOD)
GB/T 2900.15 Electrotechnical Terminology - Transformer, Instrument Transformer, Voltage Regulator and Reactor (GB/T 2900.15-1997, neq. IEC 60050-421: 1990 and IEC 60050-321: 1986)
GB/T 4798.4 Environmental Conditions Existing in the Application of Electric and Electronic Products - Part 4: Stationary Use at Non-weather-protected Locations (GB/T 4798.4-2007, IEC 60721-3-4: 1995, MOD)
GB 10230.1 Tap-changers - Part 1: Performance Requirements and Test Methods (GB 10230.1-2007, IEC 60214-1: 2003, MOD)
GB/T 19001 Requirements for Quality Management System (GB/T 19001-2008, ISO 9001: 2008, IDT)
3 Terms and Definitions
For the purposes of this document, the terms and definitions specified in GB/T 2900.15 and the following ones apply. Some are listed more than once and some are changed.
3.1 General
3.1.1
Power transformer
A static piece of apparatus with two or more windings which, by electromagnetic induction, transforms a system of alternating voltage and current into another system of voltage and current usually of different values and at the same frequency for the purpose of transmitting electrical power.
Note: GB/T 2900.15-1997, 3.1.1, modified.
3.1.2
Auto-transformer
A transformer in which at least two windings have a common part.
[GB/T 2900.15-1997, 3.1.15]
Note: Where there is a need to express that a transformer is not auto-connected, use is made of terms such as separate winding transformer, or double-wound transformer.
3.1.3
Series transformer
A transformer, other than an autotransformer, of which one winding is intended to be connected in series with a circuit in order to alter its voltage and/or shift its phase. The other winding is an energizing winding.
Note 1: GB/T 2900.15-1997, 3.1.8, modified.
Note 2: Series transformers were called booster transformers in earlier editions of this part.
3.1.4
Liquid-immersed type transformer
A transformer in which the core and windings are immersed in liquid.
[GB/T 2900.15-1997, 3.1.4]
3.1.5
Dry-type transformer
A transformer in which the core and windings are not immersed in an insulating liquid
[GB/T 2900.15-1997, 3.1.5]
3.1.6
Liquid preservation system
System in a liquid-filled transformer by which the thermal expansion of the liquid is accommodated.
Note: Contact between the liquid and external air may sometimes be diminished or prevented.
3.1.7
Specified value
The value specified by the purchaser at the time of order.
3.1.8
Design value
The expected value given by the number of turns in the design in the case of turns ratio or calculated from the design in the case of impedance, no-load current or other parameters.
3.1.9
Highest voltage for equipment applicable to a transformer winding
Um
The highest r.m.s. phase-to-phase voltage in a three-phase system.
[GB 1094.3-2003, 3.1]
3.2 Terminals and neutral point
3.2.1
Terminal
A conducting element intended for connecting a winding to external conductors.
3.2.2
Line terminal
A terminal intended for connection to a line conductor of a network.
[GB/T 2900.15-1997, 5.5.1]
3.2.3
Neutral terminal
Neutral terminal includes:
a) for three-phase transformers and three-phase banks of single-phase transformers: the terminal or terminals connected to the common point (the neutral point) of a star- connected or zigzag connected winding
b) for single-phase transformers: the terminal intended for connection to a neutral point of a network.
Note: GB/T 2900.15-1997, 5.5.2, modified.
3.2.4
Neutral point
The point of a symmetrical system of voltages which is normally at zero potential.
3.2.5
Corresponding terminal
Terminals of different windings of a transformer, marked with the same letter or corresponding symbol.
[GB/T 2900.15-1997, 2.1.28]
3.3 Windings
3.3.1
Winding
The assembly of turns forming an electrical circuit associated with one of the voltages assigned to the transformer
Note 1: GB/T 2900.15-1997, 4.3.1, modified.
Note 2: For a three-phase transformer, the 'winding' is the combination of the phase windings (see 3.3.3).
3.3.2
Tapped winding
A winding in which the effective number of turns can be changed in steps.
3.3.3
Phase winding
The assembly of turns forming one phase of a three-phase winding.
Note 1: GB/T 2900.15-1997, 4.3.16, modified.
Note 2: The term 'phase winding' shall not be used for identifying the assembly of all coils on a specific leg.
3.3.4
High-voltage winding; HV winding
The winding having the highest rated voltage
[GB/T 2900.15-1997, 4.3.2]
3.3.5
Low-voltage winding; LV winding1
The winding having the lowest rated voltage.
[GB/T 2900.15-1997, 4.3.3]
Note: For a series transformer, the winding having the lower rated voltage may be that having the higher insulation level.
3.3.6
Intermediate-voltage winding1
A winding of a multi-winding transformer having a rated voltage intermediate between the highest and lowest winding rated voltages.
[GB/T 2900.15-1997, 4.3.4]
3.3.7
Auxiliary winding
A winding intended only for a small load compared with the rated power of the transformer.
[GB/T 2900.15-1997, 4.3.11]
3.3.8
Stabilizing winding
A supplementary delta-connected winding provided in a star-star-connected or star-zigzag- connected transformer to decrease its zero-sequence impedance, see 3.7.3
Note 1: GB/T 2900.15-1997, 4.3.12, modified.
Note 2: A winding is referred to as a stabilizing winding only if it is not intended for three-phase connection to an external circuit.
3.3.9
Common winding
The common part of the windings of an auto-transformer.
[GB/T 2900.15-1997, 4.3.13]
3.3.10
Series winding
The part of the winding of an auto-transformer or the winding of a series transformer which is intended to be connected in series with a circuit.
Note: GB/T 2900.15-1997, 4.3.14, modified.
3.3.11
Energizing winding
The winding of a series transformer (or series transformer) which is intended to supply power to the series winding.
Note: GB/T 2900.15-1997, 4.3.15, modified.
3.3.12
Auto-connected windings
The series and common windings of an auto-transformer.
3.4 Rating
3.4.1
Rating
Those numerical values assigned to the quantities which define the operation of the transformer in the conditions specified in this part and on which the manufacturer's guarantees and the tests are based.
3.4.2
Rated quantities
Quantities (voltage, current, etc.), the numerical values of which define the rating.
Note 1: For transformers having tappings, rated quantities are related to the principal tapping (see 3.5.2), unless otherwise specified. Corresponding quantities with analogous meaning, related to other specific tappings, are called tapping quantities (see 3.5.9).
Note 2: Voltages and currents are always expressed by their r.m.s. values, unless otherwise specified.
3.4.3
Rated voltage of a winding
Ur
The voltage assigned to be applied, or developed at no-load, between the terminals of an untapped winding, or of a tapped winding connected on the principal tapping (see 3.5.2) , for a three-phase winding it is the voltage between line terminals.
Note 1: GB/T 2900.15-1997, 2.1.4, modified.
Note 2: The rated voltages of all windings appear simultaneously at no-load when the voltage applied to one of them has its rated value.
Note 3: For single-phase transformers intended to be connected in star to form a three-phase bank or to be connected between the line and the neutral of a three phase system, the rated voltage is indicated as the phase-to-phase voltage, divided by . Such as:
kV
Note 4: For single phase transformers intended to be connected between phases of a network, the rated voltage is indicated as the phase-to-phase voltage.
Note 5: For the series winding of a three-phase series transformer, which is designed as an open winding (see 3.10.5), the rated voltage is indicated as if the windings were connected in star.
3.4.4
Rated voltage ratio
The ratio of the rated voltage of a winding to the rated voltage of another winding associated with a lower or equal rated voltage
Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
In this part, Clause 2, Clause 3, 11.2~11.12, Clause 12, Clause 13, Annex A ~Annex F, Annex H and Annex I are recommendatory and the rest are mandatory.
GB 1094 consists of the following parts under the general title Power Transformers:
——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: Design and Application of Liquid-immersed Transformers Using High-temperature Insulation Material;
——Part 16: Wind Power Transformer.
This is part 1 of GB 1094.
This part is drafted in accordance with the rules given in the GB/T 1.1-2009.
This part supersedes GB 1094.1-1996 Power Transformers Part 1: General and has the main technical changes as follows compared with GB 1094.1-1996:
——Definition of harmonic content is added;
——Transport clause is added;
——Functional specification is added;
——Connection symbol of single-phase transformer is added;
——Safety and environmental requirements are added;
——The requirements of liquid preservation system are added;
——The clause on DC currents in neutral circuits is added;
——Test items are adjusted;
——Leak testing with pressure for liquid immersed transformers, vacuum deflection test for liquid immersed transformers, pressure deflection test for liquid immersed transformers and vacuum tightness test on site for liquid immersed transformers are added;
——Informative annexes on facilities for future fitting of condition monitoring systems to transformers and environmental and safety considerations are added.
This part is modified in relation to ISO 60076-1:2011 Power Transformers Part 1: General.
There are technical differences between this part and IEC 60076-1:2011,and the technical differences has been indicated by (｜) in the outer side page margin; see Annex A for list of technical differences and reasons.
The following editorial changes are made in this part:
——"Ei" and "Ii" in the keys of equation, in 3.13.3 of IEC 60076-1:2011 are changed to "E2i" and "I2i";
——Figure la), Figure 1b) and Figure 1c) in IEC 60076-1:2011 are combined into one figure;
——Information in "note" of 7.1.2 in IEC 60076-1:2011 is removed;
——Examples under 7.2.4 in IEC 60076-1:2011 are moved to 7.2.5;
——Structural form of Table 1 in IEC 60076-1:2011 is adjusted;
——Tap positions in Table B.2 and Table B.3 of IEC 60076-1:2011 are modified;
——Informative annex A is added, in which the technical differences between this part and IEC 60076-1:2011 and reasons are listed;
——Informative Annex B is added, in which the vacuum deflection test for liquid immersed transformers, pressure deflection test for liquid immersed transformers not included in IEC 60076-1:2011 are listed;
——Annex A, Annex B, Annex C, Annex D, Annex E, Annex F and Annex G in IEC 60076-1:2011 are renamed as Annex D, Annex E, Annex F, Annex C, Annex G, Annex H and Annex I.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. Issuing authority shall not be held responsible for identifying any or all such patent rights.
This part is proposed by the China Electrical Equipment Industry Association.
This part is under the jurisdiction of National Technical Committee on Transformer of Standardization Administration of China (SAC/TC 44).
Drafting organizations of this part: Shenyang Transformer Research Institute, State Grid Electric Power Research Institute, Baoding Tianwei Baobian Electric Co., Ltd., Sunten Electric Equipment Co., Ltd., TBEA Shenyang Transformer Co., Ltd., Xi'an XD Transformer Co., Ltd., Jilin Electric Power Research Institute, TBEA Hengyang Transformer Co., Ltd., Pearl Electric Co.,Ltd., Wujiang transformer Co., Ltd., Guangdong Julong Electric Power Equipment Co., Ltd., East China Grid Company Limited, China Electric Equipment (Jiangsu) Co., Ltd., Chint Electric Inc., Junfa Electric, Wolong Electric Yinchuan Transformer Co., Ltd.
Chief drafting staff of this part: Zhang Xianzhong, Zhang Zhongguo, Wu Zhirong, Hu Zhenzhong, Liu Yan, An Zhen, Qi Yingshi, Mi Chuanlong, Zhang Dong, Ao Ming, Sun Shubo, Cai Dingguo, Lin Canhua, Wang Wenguang, Jiang Yimin, Xu Zihong, Li Jinbiao, Fan Jianping, Lu Wei.
The previous editions of standard superseded by this part are listed as follows:
——GB 1094.1-1985, GB 1094.1-1996.
NATIONAL STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
中华人民共和国国家标准
GB 1094.1-2013
Power Transformers - Part 1: General
电力变压器 第1部分: 总则
1 Scope
This part of GB 1094 applies to three-phase and single-phase power transformers (including auto-transformers) with the exception of certain categories of small and special transformers such as:
——single-phase transformers with rated power less than 1 kVA and three-phase transformers less than 5 kVA;
——transformers, which have no windings with rated voltage higher than 1000 V;
——instrument transformers;
——traction transformers mounted on rolling stock;
——starting transformers;
——testing transformers;
——welding transformers;
——explosion-proof and mining transformers;
——transformers for deep water (submerged) applications.
When some standards do not exist for such categories of transformers (in particular transformer having no winding exceeding 1000V for industrial applications), this part may still be applicable either as a whole or in part.
This part does not address the requirements that would make a transformer suitable for mounting in a position accessible to the general public.
For those categories of power transformers and reactors which have their own standards, this part is applicable only to the extent in which it is specifically called up by cross-reference in the other standard. Such standards exist for:
——reactors (GB/T 1094.6);
——dry-type transformers (GB 1094.11);
——self-protected transformers (IEC 60076-13);
——gas-filled power transformers (IEC 60076-15);
——transformers for wind turbine applications (GB 1094.16);
——traction transformers and traction reactors (GB/T 25120);
——converter transformers for industrial applications (GB/T 18494.1);
——converter transformers for HVDC applications (GB/T 18494.2).
At several places in this part it is specified or recommended that an 'agreement' should be reached concerning alternative or additional technical solutions or procedures. Such agreement is made between the manufacturer and the purchaser. The matters should preferably be raised at an early stage and the agreements included in the contract specification.
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 1094.2 Power Transformers Part 2: Temperature Rise for Liquid-immersed Transformers (GB 1094.2-2013, IEC 60076 - 2: 2011, MOD)
GB 1094.3 Power transformers - Part 3: Insulation Levels, Dielectric Tests and External Clearances in Air (GB 1094.3-2003, IEC 60076-3: 2000, MOD)
GB 1094.5 Power Transformers - Part 5: Ability to Withstand Short Circuit (GB 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 1094.11 Power Transformers - Part 11: Dry-type Transformers (GB 1094.11-2007, IEC 60076-11: 2004, MOD)
GB/T 2521 Cold-rolled Grain-oriented and Non-oriented Magnetic steel Strip (Sheet) (GB/T 2521-2008, IEC 60404-8-7: 1998 and IEC60404-8-4: 1998, MOD)
GB 2536 Fluids for Electrotechnical Applications - Unused Mineral Insulating oils for Transformers and Switchgear(GB 2536-2011, IEC 60296: 2003, MOD)
GB/T 2900.15 Electrotechnical Terminology - Transformer, Instrument Transformer, Voltage Regulator and Reactor (GB/T 2900.15-1997, neq. IEC 60050-421: 1990 and IEC 60050-321: 1986)
GB/T 4109 Insulated Bushings for Alternating Voltages above 1 000V (GB/T 4109-2008, IEC 60137: 2008, MOD)
GB/T 4798.4 Environmental Conditions Existing in the Application of Electric and Electronic Products - Part 4: Stationary Use at Non-weather-protected Locations (GB/T 4798.4-2007, IEC 60721-3-4: 1995, MOD)
GB 10230.1 Tap-changers - Part 1: Performance Requirements and Test Methods (GB 10230.1-2007, IEC 60214-1: 2003, MOD)
GB/T 19001 Requirements for Quality Management System (GB/T 19001-2008, ISO 9001: 2008, IDT)
3 Terms and Definitions
For the purposes of this document, the terms and definitions specified in GB/T 2900.15 and the following ones apply. Some are listed more than once and some are changed.
3.1 General
3.1.1
Power transformer
A static piece of apparatus with two or more windings which, by electromagnetic induction, transforms a system of alternating voltage and current into another system of voltage and current usually of different values and at the same frequency for the purpose of transmitting electrical power.
Note: GB/T 2900.15-1997, 3.1.1, modified.
3.1.2
Auto-transformer
A transformer in which at least two windings have a common part.
[GB/T 2900.15-1997, 3.1.15]
Note: Where there is a need to express that a transformer is not auto-connected, use is made of terms such as separate winding transformer, or double-wound transformer.
3.1.3
Series transformer
A transformer, other than an autotransformer, of which one winding is intended to be connected in series with a circuit in order to alter its voltage and/or shift its phase. The other winding is an energizing winding.
Note 1: GB/T 2900.15-1997, 3.1.8, modified.
Note 2: Series transformers were called booster transformers in earlier editions of this part.
3.1.4
Liquid-immersed type transformer
A transformer in which the core and windings are immersed in liquid.
[GB/T 2900.15-1997, 3.1.4]
3.1.5
Dry-type transformer
A transformer in which the core and windings are not immersed in an insulating liquid
[GB/T 2900.15-1997, 3.1.5]
3.1.6
Liquid preservation system
System in a liquid-filled transformer by which the thermal expansion of the liquid is accommodated.
Note: Contact between the liquid and external air may sometimes be diminished or prevented.
3.1.7
Specified value
The value specified by the purchaser at the time of order.
3.1.8
Design value
The expected value given by the number of turns in the design in the case of turns ratio or calculated from the design in the case of impedance, no-load current or other parameters.
3.1.9
Highest voltage for equipment applicable to a transformer winding
Um
The highest r.m.s. phase-to-phase voltage in a three-phase system.
[GB 1094.3-2003, 3.1]
3.2 Terminals and neutral point
3.2.1
Terminal
A conducting element intended for connecting a winding to external conductors.
3.2.2
Line terminal
A terminal intended for connection to a line conductor of a network.
[GB/T 2900.15-1997, 5.5.1]
3.2.3
Neutral terminal
Neutral terminal includes:
a) for three-phase transformers and three-phase banks of single-phase transformers: the terminal or terminals connected to the common point (the neutral point) of a star- connected or zigzag connected winding
b) for single-phase transformers: the terminal intended for connection to a neutral point of a network.
Note: GB/T 2900.15-1997, 5.5.2, modified.
3.2.4
Neutral point
The point of a symmetrical system of voltages which is normally at zero potential.
3.2.5
Corresponding terminal
Terminals of different windings of a transformer, marked with the same letter or corresponding symbol.
[GB/T 2900.15-1997, 2.1.28]
3.3 Windings
3.3.1
Winding
The assembly of turns forming an electrical circuit associated with one of the voltages assigned to the transformer
Note 1: GB/T 2900.15-1997, 4.3.1, modified.
Note 2: For a three-phase transformer, the 'winding' is the combination of the phase windings (see 3.3.3).
3.3.2
Tapped winding
A winding in which the effective number of turns can be changed in steps.
3.3.3
Phase winding
The assembly of turns forming one phase of a three-phase winding.
Note 1: GB/T 2900.15-1997, 4.3.16, modified.
Note 2: The term 'phase winding' shall not be used for identifying the assembly of all coils on a specific leg.
3.3.4
High-voltage winding; HV winding
The winding having the highest rated voltage
[GB/T 2900.15-1997, 4.3.2]
3.3.5
Low-voltage winding; LV winding1
The winding having the lowest rated voltage.
[GB/T 2900.15-1997, 4.3.3]
Note: For a series transformer, the winding having the lower rated voltage may be that having the higher insulation level.
3.3.6
Intermediate-voltage winding1
A winding of a multi-winding transformer having a rated voltage intermediate between the highest and lowest winding rated voltages.
[GB/T 2900.15-1997, 4.3.4]
3.3.7
Auxiliary winding
A winding intended only for a small load compared with the rated power of the transformer.
[GB/T 2900.15-1997, 4.3.11]
3.3.8
Stabilizing winding
A supplementary delta-connected winding provided in a star-star-connected or star-zigzag- connected transformer to decrease its zero-sequence impedance, see 3.7.3
Note 1: GB/T 2900.15-1997, 4.3.12, modified.
Note 2: A winding is referred to as a stabilizing winding only if it is not intended for three-phase connection to an external circuit.
3.3.9
Common winding
The common part of the windings of an auto-transformer.
[GB/T 2900.15-1997, 4.3.13]
3.3.10
Series winding
The part of the winding of an auto-transformer or the winding of a series transformer which is intended to be connected in series with a circuit.
Note: GB/T 2900.15-1997, 4.3.14, modified.
3.3.11
Energizing winding
The winding of a series transformer (or series transformer) which is intended to supply power to the series winding.
Note: GB/T 2900.15-1997, 4.3.15, modified.
3.3.12
Auto-connected windings
The series and common windings of an auto-transformer.
3.4 Rating
3.4.1
Rating
Those numerical values assigned to the quantities which define the operation of the transformer in the conditions specified in this part and on which the manufacturer's guarantees and the tests are based.
3.4.2
Rated quantities
Quantities (voltage, current, etc.), the numerical values of which define the rating.
Note 1: For transformers having tappings, rated quantities are related to the principal tapping (see 3.5.2), unless otherwise specified. Corresponding quantities with analogous meaning, related to other specific tappings, are called tapping quantities (see 3.5.9).
Note 2: Voltages and currents are always expressed by their r.m.s. values, unless otherwise specified.
3.4.3
Rated voltage of a winding
Ur
The voltage assigned to be applied, or developed at no-load, between the terminals of an untapped winding, or of a tapped winding connected on the principal tapping (see 3.5.2) , for a three-phase winding it is the voltage between line terminals.
Note 1: GB/T 2900.15-1997, 2.1.4, modified.
Note 2: The rated voltages of all windings appear simultaneously at no-load when the voltage applied to one of them has its rated value.
Note 3: For single-phase transformers intended to be connected in star to form a three-phase bank or to be connected between the line and the neutral of a three phase system, the rated voltage is indicated as the phase-to-phase voltage, divided by . Such as:
kV
Note 4: For single phase transformers intended to be connected between phases of a network, the rated voltage is indicated as the phase-to-phase voltage.
Note 5: For the series winding of a three-phase series transformer, which is designed as an open winding (see 3.10.5), the rated voltage is indicated as if the windings were connected in star.
3.4.4
Rated voltage ratio
The ratio of the rated voltage of a winding to the rated voltage of another winding associated with a lower or equal rated voltage
Note: GB/T 2900.15-1997, 2.1.5, modified.
