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GB 1094.11-2007 English PDF (GB1094.11-2007)

GB 1094.11-2007 English PDF (GB1094.11-2007)

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GB 1094.11-2007: [GB/T 1094.11-2007] Power transformers. Part 11: Dry-type transformers

This part of GB 1094 applies to dry-type power transformers (including autotransformers), where the maximum voltage of the equipment is 40.5 kV and below, AND at least one winding is operated at a temperature higher than 1.1 kV. This part applies to dry-type transformers of various structures and processes.
GB 1094.11-2007 (Renamed to GB/T 1094.11-2007)
ICS 29.180
K 41
GB 1094.11-2007
Replacing GB 6450-1986
Power transformers - Part 11: Dry-type transformers
(IEC 60076-11:2004, MOD)
Issued by: General Administration of Quality Supervision, Inspection and Quarantine of PRC;
Standardization Administration of PRC.
This standard is changed into recommended
standard, from March 23, 2017. Its number is
changed to GB/T 1094.11-2007
Table of Contents
Foreword ... 6
1 Scope ... 9
2 Normative references ... 9
3 Terms and definitions ... 10
4 Operating conditions ... 11
4.1 Overview ... 11
4.2 Normal conditions of use ... 11
4.3 Electromagnetic compatibility (EMC) ... 12
4.4 Special conditions of use ... 12
4.5 Transportation and storage conditions ... 13
5 Taps ... 14
6 Binding group ... 14
7 Capability to withstand short circuits ... 14
8 Rated value ... 14
8.1 Overview ... 14
8.2 Rated capacity ... 14
8.3 Priority value of rated capacity ... 15
8.4 Operation above rated voltage ... 15
8.5 Operation during fan cooling ... 15
8.6 Operation in the enclosure ... 15
9 Nameplate... 16
9.1 Nameplate fixed on the transformer ... 16
9.2 Nameplate fixed on the transformer enclosure ... 17
10 Signs of cooling method ... 17
10.1 Code of signs ... 17
10.2 Arrangement of letter codes ... 17
11 Limit of temperature rise ... 18
11.1 Limit of normal temperature rise ... 18
11.2 Reduced temperature rise of transformers designed for higher cooling air temperature or special air cooling conditions ... 19
11.3 Correction of temperature rise at high altitude ... 19
12 Insulation level ... 20
12.1 Overview ... 20
12.2 Transformers used at high altitudes ... 20
13 Climate, environment and combustion performance class ... 21
13.1 Climate class ... 21
13.2 Environmental class ... 21
13.3 Combustion performance class ... 22
13.4 Test criteria for climatic, environmental, combustion performance class ... 22 14 General requirements for testing ... 23
15 Measurement of winding resistance (routine test) ... 23
16 Measurement of voltage ratio and verification of binding group number (routine test) ... 23
17 Measurement of short-circuit impedance and load loss (routine test) ... 23 18 Measurement of no-load loss and no-load current (routine test) ... 24 19 Applied withstand voltage test (routine test) ... 24
20 Induction withstand voltage test (routine test) ... 24
21 Lightning impulse test (type test) ... 24
22 Measurement of partial discharge (routine test and special test) ... 25 22.1 Overview ... 25
22.2 Basic measurement circuit (only typical circuit) ... 25
22.3 Calibration of measuring circuit ... 26
22.4 Voltage application method ... 27
22.5 Acceptance level of partial discharge ... 28
23 Test of temperature rise (type test) ... 28
23.1 Overview ... 28
23.2 Method of applying load ... 28
23.3 Correction of winding's temperature rise under reduced current ... 32 23.4 Determination of steady-state conditions ... 32
24 Measurement of sound level (special test) ... 33
25 Short-circuit withstand capability test (special test) ... 33
26 Environmental test (special test) ... 33
26.1 Overview ... 33
26.2 Validity of test ... 33
26.3 Test procedure ... 33
27 Climatic test (special test) ... 35
27.1 Overview ... 35
27.2 Validity of test ... 35
27.3 Climatic test (thermal shock test) for grade C1 transformers ... 36 27.4 Climatic test (thermal shock test) of grade C2 transformer ... 38 28 Combustion performance test (special test) ... 38
28.1 Overview ... 38
28.2 Detection of corrosive and harmful gas escape ... 38
28.3 Combustion performance test of grade F1 transformer ... 39
28.4 Parameters to be measured and measuring devices ... 43
28.5 Calibration of the test chamber without the sample ... 44
28.6 Test method ... 44
28.7 Test report ... 45
28.8 Evaluation criteria for test results ... 45
29 Deviation ... 46
30 Protection against direct contact ... 46
31 Degree of protection of enclosure ... 46
32 Grounding terminal ... 46
33 Information needed for inquiries and orders ... 47
34 Information on installation and safety ... 47
Appendix A (Informative) Comparison of the number of chapters, clauses, tables between this part and IEC 60076-11:2004 ... 48
Appendix B (Informative) Technical differences between this part and IEC 60076-11:2004 and their reasons ... 49
Appendix C (Informative) Insulation level of North America in IEC 60076- 11:2004 ... 51
Appendix D (Informative) Installation and safety of dry-type transformers ... 52 Foreword
Chapter 1, Chapter 2, Chapter 3, Chapter 6, Chapter 33, Chapter 34 of this part are recommended. The rest are mandatory.
GB 1094 "Power transformers" currently contains the following parts:
- Part 1: General;
-Part 2: Temperature rise;
- 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 10: Determination of sound;
- Part 11: Dry-type transformers.
This part is Part 11 of GB 1094. The number of the previous version of this part is GB 6450. The corresponding IEC standard number is IEC 60726. As the
standard numbers of IEC related power transformers are now adjusted to the IEC 60076 series, in order to be in harmony with the IEC standard numbers AND convenient to use, this revision also adjusts the standard numbers, based on the new IEC standard series.
This part modifies and adopts IEC 60076-11:2004 "Power transformer - Part 11: Dry-type transformer" (English version).
This part is redrafted in accordance with IEC 60076-11:2004 in accordance with the redrafting principles. The numbering of the figure in this part is completely consistent with IEC 60076-11:2004, whilst the numbering of some chapters, clauses, tables are not completely consistent with IEC 60076-11:2004. The comparison list is given in Appendix A.
Taking into account the current conditions of China, when adopting IEC 60076- 11:2004, some technical content has been modified in this part. The differences have been incorporated into the main text AND marked with a vertical single line in the margins of the clauses they involve. A list of these technical differences and their reasons is given in Appendix B, for reference.
For ease of use, this part also makes the following editorial changes to IEC 60076-11:2004:
a) DELETE the forewords of IEC 60076-11:2004;
b) USE a decimal point ".", to replace the comma "," which was used as a decimal point;
c) According to GB/T 1.1-2000 "Directives for standardization-Part 1: Rules for the structure and drafting of standards", MODIFY the format of Table 1 in IEC 60076-11:2004.
This part replaces GB 6450-1986 "Dry-type power transformer".
Compared with GB 6450-1986, the main changes in this part are as follows: - ADD the "Normative references";
- CANCEL the definitions of "dry-type transformers with encapsulated coils", "dry-type transformers with non-encapsulated coils", "sealed dry-type
- ADD some "conditions of use"; ADD "transportation and storage conditions"; - MODIFY the relevant provisions on the correction of temperature rise limit and insulation level of transformers, which are used for special conditions of use;
- MODIFY the rated short-time applied withstand voltage of the transformer, which has a nominal system voltage of 10 kV;
- ADD the technical requirements, test items, test methods for "climate, environment, combustion performance level";
- MODIFY the relevant technical requirements and test methods of "partial discharge measurement";
- MODIFY the relevant requirements of the "temperature rise test";
- ADD the requirements for "protection against direct contact", "grounding terminal", "installation and safety information".
Appendix A, Appendix B, Appendix C, Appendix D of this part are all informative appendixes.
This part was proposed by the China Electrical Equipment Industry Association. This part shall be under the jurisdiction of the National Transformer
Standardization Technical Committee (SAC/TC 44).
Drafting organizations of this part: Shenyang Transformer Research Institute, Power transformers - Part 11: Dry-type transformers
1 Scope
This part of GB 1094 applies to dry-type power transformers (including
autotransformers), where the maximum voltage of the equipment is 40.5 kV and below, AND at least one winding is operated at a temperature higher than 1.1 kV. This part applies to dry-type transformers of various structures and processes.
This part does not apply to:
- Inflatable dry-type transformer (when the inflatable gas is not air); - Single-phase transformer, which has a rated capacity of less than 5 kVA; - Multi-phase transformer, which has a rated capacity of less than 15 kVA; - Transducer;
- Starting transformer;
- Test transformer;
- Locomotive traction transformer;
- Flameproof and mining transformers;
- Welding transformer;
- Voltage regulating transformer;
- Small power transformers that focus on safety.
When the above-mentioned transformers or other special transformers do not have corresponding standards, this part can be applied in whole or in part. 2 Normative references
The provisions in following documents become the provisions of this part through reference in GB 1094. For the dated references, the subsequent
amendments (excluding corrections) or revisions do not apply to this part; however, parties who reach an agreement based on this part are encouraged to study if the latest versions of these documents are applicable. For undated references, the latest edition of the referenced document applies.
GB 311.1 Insulation co-ordination for high voltage transmission and
distribution equipment (GB 311.1-1997, neq IEC 60071-1:1993)
GB 1094.1 Power transformers - Part 1: General (GB 1094.1-1996, eqv IEC 60076-1:1993)
GB 1094.2 Power transformers - Part 2: Temperature rise (GB 1094.2-1996, eqv IEC 60076-2:1993)
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 1094.5-2003, IEC 60076-5: 2000, MOD)
GB/T 1094.10 Power transformers - Part 10: Determination of sound (GB/T 1094.10-2003, IEC 60076-10:2001, MOD)
GB/T 2900.15 Electrotechnical terminology - Transformer, instrument
transformer, voltage regulator and reactor (GB/T 2900.15-1997, neq IEC
60050-421:1990, IEC 60050-321:1986)
GB 4208 Degrees of protection provided by enclosure (IP code) (GB 4208- 1993, eqv IEC 60529:1989)
GB/T 7354 Partial discharge measurements (GB/T 7354-2003, IEC
60270:2000, IDT)
GB/T 11021 Thermal evaluation and classification of electrical insulation (GB/T 11021-1989, eqv IEC 60085:1984)
GB/T 17211-1998 Loading guide for dry-type power transformers (eqv IEC
GB/T 17467 High-voltage/low-voltage prefabricated substations (GB/T
17467-1998, eqv IEC 61330:1995)
GB/T 18380.3 Tests on electric cables under fire conditions - Part 3: Tests on bunched wires or cables (GB/T 18380.3-2001, idt IEC 60332-3:1992)
3 Terms and definitions
The terms and definitions as defined in GB/T 2900.15, as well as the following terms and definitions, apply to this part.
temperature rise test.
23.2.1 Simulated load method
This method is suitable for non-enclosed, enclosed or fully enclosed dry-type self-cooled or air-cooled transformers.
The temperature rise value is determined, by a combination of short-circuit test (providing load loss) AND no-load test (providing no-load loss).
At the beginning of the test, the temperature of the transformer shall be as stable as the ambient temperature of the test room. It shall measure the resistance values of the high and low voltage windings. These measured values will be used as the reference values, for calculating the temperature rise of the two windings. The ambient temperature of the test room shall also be measured and recorded.
For a three-phase transformer, the resistance measurement shall be carried out, between the middle phase and the wire terminal of one side phase winding. The position of each temperature measurement point [i.e.: the thermometer for measuring the ambient temperature AND the sensor on the transformer (if any)], shall be same, regardless of whether it is a reference measurement or a final measurement.
The winding's short-circuit test shall be carried out under the condition, that the rated current flows through one winding, whilst the other winding is short- circuited; it continues until the temperature of the winding and the core reaches a steady state, as shown in 23.4. Use resistance method or superposition method, to determine the temperature rise Δθc of each winding.
The no-load test, at rated frequency and rated voltage, shall be continued, until the winding and core temperature reach a steady state. Then it shall measure the temperature rise Δθe of the respective windings.
The test procedure for temperature rise shall use one of the following two methods:
- Perform short-circuit test for the winding first, until the core and winding temperature reaches a stable level; then perform no-load test, until the temperature of the core and winding reaches a stable level;
- First carry out the no-load test, until the temperature of the core and winding reaches a stable level; then carry out a short-circuit test of the winding, until the temperature of the core and winding reaches a stable level.
When the rated current passes through the winding AND the core is at the rated test period.
Before and after the test, it shall weigh the mass of the test product; the weighing accuracy shall be ±0.5% or higher. The iron core post and the coil with insulating parts can be weighed separately.
28.7 Test report
The test report shall contain the following information:
a) Test results of material samples (if required by the user);
b) Calculated mass, thermal energy value (if possible), measured mass of sample of combustible materials;
c) The calibration results of the test chamber (air flow, temperature in the measurement segment, adjustment of the regulating valve or air
extraction system, etc.);
d) A comprehensive description of the test method, including alcohol burning time and energized heating time;
e) The calculated value of the mass loss of combustible materials (accuracy of ±10%) AND the heat released (MJ) (if possible), during the test;
f) The temperature record value of the whole test process, from the beginning of the test (starting when the alcohol is ignited); record it once every 2 minutes or less;
g) The continuous recorded value (%) of the visible light, which is transmitted in the measurement segment, during the entire test;
h) During the entire test, the air flow (m3/s) in the measurement segment, which is measured once every 2 minutes or less;
i) The burning state visible on the sample.
28.8 Evaluation criteria for test results
If the test product meets the following requirements, the test is considered qualified:
a) During the entire test, the temperature rise of the gas in the measurement segment, in the chimney, to the ambient temperature shall not exceed 420 K;

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