GB/T 10230.2-2025 Tap-changers - Part 2: Application guide
1 Scope
This document provides relevant information including references, definitions, requirements, selection and use related to GB/T 10230.1, which helps all parties to further understand various types of tap-changers and their auxiliary devices.
This document is applicable to providing technical guidance for the selection and use of on-load tap-changers (resistor type and reactor type) and de-energized tap-changers connected to the tapped windings of transformers, reactors and other equipment that meet the requirements of GB/T 10230.1.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions 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 507 Insulating liquids - Determination of the breakdown voltage at power frequency (GB/T 507-2002, IEC 60156:1995, IDT)
GB/T 1094.1-2013 Power transformers - Part 1: General (IEC 60076-1:2011, MOD)
Note: There are no technical differences between the referenced content from GB/T 1094.1-2013 and that from IEC 60076-1:2011.
GB/T 1094.3-2017 Power transformers - Part 3:Insulation levels, dielectric tests and external clearances in air (IEC 60076-3:2013, MOD)
Note: There are no technical differences between the referenced content from GB/T 1094.3-2017 and that from IEC 60076-3:2013.
GB/T 1094.5-2008 Power transformers - Part 5: Ability to withstand short circuit (IEC 60076-5:2006, MOD)
Note: There are no technical differences between the referenced content from GB/T 1094.5-2008 and that from IEC 60076-5:2006.
GB/T 1094.6 Power transformers - Part 6: Reactors (GB/T 1094.6-2011, IEC 60076-6:2007, MOD)
GB/T 1094.7 Power transformers - Part 7: Loading guide for mineral-oil-immersed power transformers (GB/T 1094.7-2024, IEC 60076-7:2018, MOD)
GB/T 1094.11 Power transformers - Part 11: Dry-type transformers (GB/T 1094.11-2022, IEC 60076-11:2018, MOD)
GB 2536 Fluids for electrotechnical applications - Unused mineral insulating oils for transformers and switchgear (GB 2536-2011, IEC 60296:2003, MOD)
GB/T 2900.95 Electrotechnical terminology - Transformers, voltage regulators and reactors (GB/T 2900.95-2015, IEC 60050-421:1990, NEQ)
GB/T 10230.1-2019 Tap-changers - Part 1: Performance requirements and test methods (IEC 60214-1:2014, MOD)
Note: There are no technical differences between the referenced content from GB/T 10230.1-2019 and that from IEC 60214-1:2014.
GB/T 17623 Determination of componental contents of gases dissolved in insulating oil by gas chromatography method
GB/T 41146 Method of sampling insulating liquids (GB/T 41146-2021, IEC 60475:2011, IDT)
IEC 60076-21 Power transformers - Part 21: Standard requirements, terminology, and test code for step-voltage regulators
IEC 60422 Mineral insulating oils in electrical equipment - Supervision and maintenance guidance
Note: GB/T 14542-2017 Guide for maintenance and supervision of transformer oil (IEC 60422:2013, NEQ)
IEC 60599 Mineral oil-filled electrical equipment in service - Guidance on the interpretation of dissolved and free gases analysis
IEC 60814 Insulating liquids - Oil-impregnated paper and pressboard - Determination of water by automatic coulometric Karl Fischer titration
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.95, GB/T 10230.1 and IEC 60076-21 as well as the following apply.
3.1
mechanically linear de-energized tap-changer
de-energized tap-changer in which the stationary contacts are arranged in a straight line and the moving contacts move in a linear manner
Note: This term applies only to the general operating characteristics of the switch, not to the type of contacts or the actual operating mechanism.
3.2
mechanically rotary de-energized tap-changer
de-energized tap-changer in which the stationary contacts are arranged along a circumference and the moving contacts move in a rotational manner
Note: This term applies only to the general operating characteristics of the switch, not to the type of contacts or the actual operating mechanism.
3.3
fritting
electrically intimate metal-to-metal contact created by the dielectric breakdown of very thin films of oil, oxides, sulfides, etc.
3.4
continuous consecutive operation
uninterrupted operation with the driving mechanism operating at its normal speed
4 Abbreviations
For the purposes of this document, the following abbreviations apply:
ARS: Advance retard switch
AV: Applied voltage test
DETC: De-energized tap-changer
DGA: Dissolved and free gases analysis
EAF: Electrical arc furnace
GIC: Geomagnetic induced current
HV: High-voltage
HVDC: High-voltage direct current
IGBT: Insulated-gate bipolar transistor
LCSET: Lowest cold start energizing temperature
LV: Low-voltage
MV: Middle-voltage
OLTC: On-load tap-changer
PD: Partial discharge
PST: Phase-shifting transformer
VI: Vacuum interrupter
VSR: Variable shunt reactor
5 Application of tap-changers for transformers and reactors
5.1 General
Tap-changers are devices that vary the active turns in the winding of a transformer or reactor. They can perform this operation either when the transformer is on load or de-energized. Therefore, they are generally divided into two fundamental types as follows:
——OLTC;
——DETC.
When the operation of the tap-changer changes the excitation level of the device to which it is applied, the volts per turn of all windings wound on the same core will change.
Tap-changers are used with all types of distribution transformers, power transformers and reactors. Transformers for special applications (e.g. HVDC transformers, PSTs, EAF transformers, etc.) are also equipped with tap-changers.
5.2 Typical circuits for regulation
Figure 1 shows a common arrangement of tap-changers in a typical star-connected winding. In these applications, a compact three-phase tap-changer without full insulation between phases may be used when applicable.
Contents
Foreword i
Introduction vi
1 Scope
2 Normative references
3 Terms and definitions
4 Abbreviations
5 Application of tap-changers for transformers and reactors
6 Types of tap-changers
7 On-load tap-changers (OLTCs)
8 De-energized tap-changers (DETCs)
9 Protective devices for OLTCs
10 Fittings and accessories for OLTCs
11 Storage and installation of the tap-changer
12 Field service (operation, maintenance and monitoring)
13 Safety
14 Information to be provided by the transformer manufacturer
Bibliography
Figure 1 Tap-changers in star-connected windings
Figure 2 Tap-changers in series transformers
Figure 3 Tap-changers in delta-connected windings
Figure 4 Tap-changers in autotransformers
Figure 5 Basic arrangements of the tapped winding
Figure 6 Common connection arrangements
Figure 7 Operating sequence of the diverter switch [d) to i)] and tap selector [a) to c)] (non-vacuum type diverter switch with operating cycle number 1)
Figure 8 Operating sequence of the selector switch (non-vacuum type selector switch with operating cycle number 1)
Figure 9 Diagram of connections of non-vacuum, resistor type OLTCs (Table B.1 of GB/T 10230.1-2019)
Figure 10 Diagram of connections of vacuum, resistor type on-load tap-changers (OLTCs) (Table B.3 of GB/T 10230.1-2019)
Figure 11 Operating sequence of the diverter switch and tap selector (non-vacuum type)
Figure 12 Diagram of connections of non-vacuum, reactor type on-load tap-changers (OLTCs) (Annex C of GB/T 10230.1-2019)
Figure 13 Diagram of connections of reactor type on-load tap-changer (OLTC) with vacuum interrupter (VI) and tap selector (Annex C of GB/T 10230.1-2019)
Figure 14 Common layouts for compartment type tap-changers
Figure 15 Common layouts for in-tank type tap-changers
Figure 16 Common arrangements of DETCs in the transformer main tank
Figure 17 Externally mounted diverter switch compartment with an in-tank tap selector and a barrier board
Figure 18 ARS application and mode of operation in a PST
Figure 19 Selector at both fine tap and coarse winding
Figure 20 Tap-changer oil conservator arrangement
Figure 21 Current splitting in DETCs
Figure 22 Types of in-tank OLTC installations within the transformer
Standard
GB/T 10230.2-2025 Tap-changers - Part 2: Application guidelines (English)
GB/T 10230.2-2025 Tap-changers - Part 2: Application guide
1 Scope
This document provides relevant information including references, definitions, requirements, selection and use related to GB/T 10230.1, which helps all parties to further understand various types of tap-changers and their auxiliary devices.
This document is applicable to providing technical guidance for the selection and use of on-load tap-changers (resistor type and reactor type) and de-energized tap-changers connected to the tapped windings of transformers, reactors and other equipment that meet the requirements of GB/T 10230.1.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions 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 507 Insulating liquids - Determination of the breakdown voltage at power frequency (GB/T 507-2002, IEC 60156:1995, IDT)
GB/T 1094.1-2013 Power transformers - Part 1: General (IEC 60076-1:2011, MOD)
Note: There are no technical differences between the referenced content from GB/T 1094.1-2013 and that from IEC 60076-1:2011.
GB/T 1094.3-2017 Power transformers - Part 3:Insulation levels, dielectric tests and external clearances in air (IEC 60076-3:2013, MOD)
Note: There are no technical differences between the referenced content from GB/T 1094.3-2017 and that from IEC 60076-3:2013.
GB/T 1094.5-2008 Power transformers - Part 5: Ability to withstand short circuit (IEC 60076-5:2006, MOD)
Note: There are no technical differences between the referenced content from GB/T 1094.5-2008 and that from IEC 60076-5:2006.
GB/T 1094.6 Power transformers - Part 6: Reactors (GB/T 1094.6-2011, IEC 60076-6:2007, MOD)
GB/T 1094.7 Power transformers - Part 7: Loading guide for mineral-oil-immersed power transformers (GB/T 1094.7-2024, IEC 60076-7:2018, MOD)
GB/T 1094.11 Power transformers - Part 11: Dry-type transformers (GB/T 1094.11-2022, IEC 60076-11:2018, MOD)
GB 2536 Fluids for electrotechnical applications - Unused mineral insulating oils for transformers and switchgear (GB 2536-2011, IEC 60296:2003, MOD)
GB/T 2900.95 Electrotechnical terminology - Transformers, voltage regulators and reactors (GB/T 2900.95-2015, IEC 60050-421:1990, NEQ)
GB/T 10230.1-2019 Tap-changers - Part 1: Performance requirements and test methods (IEC 60214-1:2014, MOD)
Note: There are no technical differences between the referenced content from GB/T 10230.1-2019 and that from IEC 60214-1:2014.
GB/T 17623 Determination of componental contents of gases dissolved in insulating oil by gas chromatography method
GB/T 41146 Method of sampling insulating liquids (GB/T 41146-2021, IEC 60475:2011, IDT)
IEC 60076-21 Power transformers - Part 21: Standard requirements, terminology, and test code for step-voltage regulators
IEC 60422 Mineral insulating oils in electrical equipment - Supervision and maintenance guidance
Note: GB/T 14542-2017 Guide for maintenance and supervision of transformer oil (IEC 60422:2013, NEQ)
IEC 60599 Mineral oil-filled electrical equipment in service - Guidance on the interpretation of dissolved and free gases analysis
IEC 60814 Insulating liquids - Oil-impregnated paper and pressboard - Determination of water by automatic coulometric Karl Fischer titration
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 2900.95, GB/T 10230.1 and IEC 60076-21 as well as the following apply.
3.1
mechanically linear de-energized tap-changer
de-energized tap-changer in which the stationary contacts are arranged in a straight line and the moving contacts move in a linear manner
Note: This term applies only to the general operating characteristics of the switch, not to the type of contacts or the actual operating mechanism.
3.2
mechanically rotary de-energized tap-changer
de-energized tap-changer in which the stationary contacts are arranged along a circumference and the moving contacts move in a rotational manner
Note: This term applies only to the general operating characteristics of the switch, not to the type of contacts or the actual operating mechanism.
3.3
fritting
electrically intimate metal-to-metal contact created by the dielectric breakdown of very thin films of oil, oxides, sulfides, etc.
3.4
continuous consecutive operation
uninterrupted operation with the driving mechanism operating at its normal speed
4 Abbreviations
For the purposes of this document, the following abbreviations apply:
ARS: Advance retard switch
AV: Applied voltage test
DETC: De-energized tap-changer
DGA: Dissolved and free gases analysis
EAF: Electrical arc furnace
GIC: Geomagnetic induced current
HV: High-voltage
HVDC: High-voltage direct current
IGBT: Insulated-gate bipolar transistor
LCSET: Lowest cold start energizing temperature
LV: Low-voltage
MV: Middle-voltage
OLTC: On-load tap-changer
PD: Partial discharge
PST: Phase-shifting transformer
VI: Vacuum interrupter
VSR: Variable shunt reactor
5 Application of tap-changers for transformers and reactors
5.1 General
Tap-changers are devices that vary the active turns in the winding of a transformer or reactor. They can perform this operation either when the transformer is on load or de-energized. Therefore, they are generally divided into two fundamental types as follows:
——OLTC;
——DETC.
When the operation of the tap-changer changes the excitation level of the device to which it is applied, the volts per turn of all windings wound on the same core will change.
Tap-changers are used with all types of distribution transformers, power transformers and reactors. Transformers for special applications (e.g. HVDC transformers, PSTs, EAF transformers, etc.) are also equipped with tap-changers.
5.2 Typical circuits for regulation
Figure 1 shows a common arrangement of tap-changers in a typical star-connected winding. In these applications, a compact three-phase tap-changer without full insulation between phases may be used when applicable.
Contents of GB/T 10230.2-2025
Contents
Foreword i
Introduction vi
1 Scope
2 Normative references
3 Terms and definitions
4 Abbreviations
5 Application of tap-changers for transformers and reactors
6 Types of tap-changers
7 On-load tap-changers (OLTCs)
8 De-energized tap-changers (DETCs)
9 Protective devices for OLTCs
10 Fittings and accessories for OLTCs
11 Storage and installation of the tap-changer
12 Field service (operation, maintenance and monitoring)
13 Safety
14 Information to be provided by the transformer manufacturer
Bibliography
Figure 1 Tap-changers in star-connected windings
Figure 2 Tap-changers in series transformers
Figure 3 Tap-changers in delta-connected windings
Figure 4 Tap-changers in autotransformers
Figure 5 Basic arrangements of the tapped winding
Figure 6 Common connection arrangements
Figure 7 Operating sequence of the diverter switch [d) to i)] and tap selector [a) to c)] (non-vacuum type diverter switch with operating cycle number 1)
Figure 8 Operating sequence of the selector switch (non-vacuum type selector switch with operating cycle number 1)
Figure 9 Diagram of connections of non-vacuum, resistor type OLTCs (Table B.1 of GB/T 10230.1-2019)
Figure 10 Diagram of connections of vacuum, resistor type on-load tap-changers (OLTCs) (Table B.3 of GB/T 10230.1-2019)
Figure 11 Operating sequence of the diverter switch and tap selector (non-vacuum type)
Figure 12 Diagram of connections of non-vacuum, reactor type on-load tap-changers (OLTCs) (Annex C of GB/T 10230.1-2019)
Figure 13 Diagram of connections of reactor type on-load tap-changer (OLTC) with vacuum interrupter (VI) and tap selector (Annex C of GB/T 10230.1-2019)
Figure 14 Common layouts for compartment type tap-changers
Figure 15 Common layouts for in-tank type tap-changers
Figure 16 Common arrangements of DETCs in the transformer main tank
Figure 17 Externally mounted diverter switch compartment with an in-tank tap selector and a barrier board
Figure 18 ARS application and mode of operation in a PST
Figure 19 Selector at both fine tap and coarse winding
Figure 20 Tap-changer oil conservator arrangement
Figure 21 Current splitting in DETCs
Figure 22 Types of in-tank OLTC installations within the transformer
