Detail of GB 1208-2006

Introduction of GB 1208-2006

1 Scope This Standard applies to newly manufactured current transformers for use with electrical measuring instruments and electrical protective devices at frequencies from 15 Hz to 100 Hz. Although the requirements relate basically to transformers with separate windings, they are also applicable, where appropriate, to autotransformers. Chapter 13 covers the requirements and tests, in addition to those in Chapter 4 to Chapter 11, that are necessary for current transformers for use with electrical measuring instruments. Chapter 14 covers the requirements and tests, in addition to those in Chapter 4 to Chapter 11, that are necessary for current transformers for use with electrical protective relays, and in particular for forms of protection in which the prime requirement is the maintenance of accuracy up to several times the rated current. For certain protective systems, where the current transformer characteristics are dependant on the overall design of the protective equipment (for example high-speed balanced systems and earth-fault protection in resonant earthed networks), additional requirements are given in Chapter 15 for class PR transformers and in Chapter 16 for class PX transformers. Chapter 15 covers the requirements and tests in addition to those in Chapter 4 to Chapter 11 that are necessary for current transformers for use with electrical protective relays, and in particular for forms of protection in which the prime requirement is the absence of remanent flux. Chapter 16 covers the requirements and tests in addition to those in Chapter 4 to Chapter 11 that are necessary for current transformers for use with electrical protective relays, and in particular for forms of protection for which knowledge of the transformer’s secondary excitation characteristic, secondary winding resistance, secondary burden resistance and turns ratio is sufficient to assess its performance in relation to the protective relay system with which it is to be used. Current transformers intended for both measurement and protection shall comply with all the clauses of this standard. 2 Normative References The following normative documents contain provisions which, through reference in this text, constitute provisions of this Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. GB 156-2003 Standard Voltages (IEC 60038:1983 + A1:1994 + A2:1997, IEC standard voltages, MOD) GB 311.1-1997 Insulation Co-ordination for High Voltage Transmission and Distribution Equipment (neq IEC 60071-1:1993) GB/T 2900.15-1997 Electrotechnical Terminology — Transformer, Instrument Transformer, Voltage Regulator and Reactor (neq IEC 60050(421):1990, IEC 60050(321):1986) GB/T 3954-2001 Aluminium Rod for Electrical Purpose GB/T 4796 Classification of Environmental Parameters and Their Severities of Electric and Electronic Products (GB/T 4796-2001, idt IEC 60721-1:1990) GB 5585.1-1985 Copper or Aluminium and its Alloy Bus Bars for Electrical Purposes — Part 1: General (neq IEC 60028:1925) GB/T 7252-2001 Guide to the Analysis and the Diagnosis of Gases Dissolved in Transformer Oil (neq IEC 60599:1999) GB/T 7354-2003 Partial Discharge Measurements (IEC 60270:2000, Partial discharge measurements, IDT) GB/T 7595-2000 Quality Criteria of Transformer Oils in Service GB/T 11021-1989 Thermal Evaluation and Classification of Electrical Insulation (eqv IEC 60085:1984) GB/T 11604 Test Methods for Measuring Radio Interference from High Voltage Equipment (GB/T 11604-1989, eqv CISPR 18-1:1982, CISPR 18-2:1986) GB/T 13384-1992 General Specification for Packagings of Mechanical and Electrical Products GB 16847-1997 Requirements for Protective Current Transformers for Transient Performance (idt IEC 60044-6:1992) GB/T 16927.1-1997 High Voltage Test Techniques — Part 1: General Test Requirements (eqv IEC 60060-1:1989) GB/T 17623-1998 Determination of Componental Contents of Gases Dissolved in Insulating Oil by Gas Chromatography Method (neq IEC 60567:1992) JB/T 5356 Test Guide for Current Transformers Test (JB/T 5356-2002) JB/T 5895-1991 Guide for the Selection of Insulators in Respect of Polluted Conditions (neq IEC 60815:1986)

Contents of GB 1208-2006

Foreword VI 1 Scope 2 Normative References 3 Terms and Definitions 3.1 General definitions 3.2 Additional definitions for measuring current transformers 3.3 Additional definitions for protective current transformers 4 Normal and Special Service Conditions 4.1 Normal service conditions Table 1 Temperature Categories 4.2 Special service conditions 4.3 System earthing 5 Ratings 5.1 Standard values of rated primary currents 5.2 Standard values of rated secondary currents 5.3 Rated continuous thermal current 5.4 Standard values of rated output 5.5 Short-time current ratings Table 2 Limits of Temperature Rise of the Windings 6 Design Requirements 6.1 Insulation requirements Table 3 Rated Insulation Levels for Transformer Primary Windings having Highest Voltage for Equipment Um < 300 kV Table 4 Rated Insulation Levels for Transformer Primary Windings having Highest Voltage for Equipment Um ≥ 300 kV Table 5 Power Frequency Withstand Voltages for Transformer Primary Windings having Highest Voltage for Equipment Um ≥ 300 kV Table 6 Partial Discharge Test Voltages and Permissible Levels Table 7 Creepage Distances Table 8 Transmitted Overvoltage Limits 6.2 Mechanical requirements Table 9 Static Withstand Test Loads 6.3 General structural requirements 7 Classification of Tests 7.1 Type tests 7.2 Routine tests 7.3 Special tests 8 Type Tests 8.1 Short-time current tests 8.2 Temperature-rise test 8.3 Impulse tests on primary winding 8.4 Wet test for outdoor type transformers 8.5 Radio interference voltage measurement Figure 1 Measuring Circuit of RIV 8.6 Insulation thermal stability test 9 Routine Tests 9.1 Verification of terminal markings 9.2 Power-frequency withstand tests on primary windings and partial discharge measurement Figure 2 Test Circuit for Partial Discharge Measurement Figure 3 Alternative Test Circuit for Partial Discharge Measurement Figure 4 Example of Balanced Test Circuit for Partial Discharge Measurement Figure 5 Example of Calibration Circuit for Partial Discharge Measurement 9.3 Power-frequency withstand tests between sections of primary and secondary windings and on secondary windings 9.4 Inter-turn overvoltage test 9.5 Measurement of capacitance and dielectric dissipation factor 9.6 Insulating oil performance test 9.7 Sealing performance test 10 Special Tests 10.1 Chopped impulse test on primary winding 10.2 Mechanical tests Table 10 Modalities of Application of Test Loads to be Applied to the Primary Terminals 10.3 Transmitted overvoltages measurement Figure 6 Transmitted Overvoltages Measurement: Test Circuit and GIS Test Set-up Figure 7 Transmitted Overvoltages Measurement: General Test Set-up 11 Markings 11.1 Terminal markings Table 11 Markings of Terminals 11.2 Rating plate markings 12 Packaging, Storage, Transportation and Accompanying Documents 12.1 Packaging 12.2 Storage and transportation 12.3 Accompanying documents 12.4 Others 13 Additional Requirements for Measuring Current Transformers 13.1 Accuracy class for measuring current transformers 13.2 Limits of current error and phase displacement for measuring current transformers Table 12 Limits of Current Error and Phase Displacement for Measuring Current Transformers (Classes from 0.1 to 1) Table 13 Limits of Current Error and Phase Displacement for Measuring Current Transformers for Special Application Table 14 Limits of Current Error for Measuring Current Transformers (Classes 3 and 5) 13.3 Extended current ratings 13.4 Type tests for accuracy of measuring current transformers 13.5 Routine tests for accuracy of measuring current transformers 13.6 Instrument security factor 13.7 Marking of the rating plate of a measuring current transformer 14 Additional Requirements for Protective Current Transformers 14.1 Standard accuracy limit factors 14.2 Accuracy classes for protective current transformer 14.3 Limits of errors for protective current transformers Table 15 Limits of Error for Protective Current Transformers 14.4 Type and routine tests for current error and phase displacement of protective current transformers 14.5 Type tests for composite error 14.6 Routine tests for composite error 14.7 Marking of the rating plate of a protective current transformer 15 Additional Requirements for Class PR Protective Current Transformers 15.1 Standard accuracy limit factors 15.2 Accuracy classes for class PR protective current transformers 15.3 Limits of error for class PR protective current transformers Table 16 Limits of Error for Class PR Protective Current Transformers 15.4 Type and routine tests for current error and phase displacement of class PR protective current transformers 15.5 Marking of rating plate of class PR current transformers 16 Additional Requirements for Class PX Protective Current Transformers 16.1 Specification of performance for class PX protective current transformers 16.2 Insulation requirements for class PX protective current transformers 16.3 Type tests for class PX protective current transformers 16.4 Routine tests for class PX protective current transformers 16.5 Marking of rating plate of class PX current transformers Appendix A (Informative) Comparison between Chapter and Article Numbers of This Standard and Those of IEC 60044-1: Table A.1 Comparison of Chapter and Article Numbers of This Standard to Those of IEC 60044-1: Table A.2 Comparison of Figure and Table Numbers of This Standard to Those of IEC 60044-1: Appendix B (Informative) Technical Differences between this Standard and IEC 60044-1:2003 and Their Reasons Table B.1 Technical Differences between This Standard and IEC 60044-1:2003 and Their Reasons Appendix C (Normative) Protective Current Transformers C.1 Vector diagram Figure C C.2 Turns correction C.3 The error triangle Figure C C.4 Composite error Figure C C.5 Direct test for composite error Figure C Figure C C.6 Alternative method for the direct measurement of composite error Figure C C.7 Use of composite error Appendix D (Informative) Altitude and Insulation Levels for Primary Windings Specified in IEC 60044-1: D.1 Altitude Figure D.1 Altitude Correction Factors D.2 Rated insulation levels for primary windings Table D.1 Rated Insulation Levels for Transformer Primary Windings Having Highest Voltage for Equipment Um < 300 kV Table D.2 Rated Insulation Levels for Transformer Primary Windings Having Highest Voltage for Equipment Um ≥ 300 kV D.3 Power-frequency withstand voltage for primary winding insulation Table D.3 Power Frequency Withstand Voltages for Transformer Primary Windings Having Highest Voltage for Equipment Um ≥ 300 kV D.4 Chopped lightning impulse withstand voltage Appendix E (Normative) Chopped Lightning Impulse Withstand Voltage Appendix F (Normative) Allowable Value of Dielectric Dissipation Factor of Current Transformers Appendix G (Informative) Multiple Chopped Impulse Test Figure 1 Measuring Circuit of RIV Figure 2 Test Circuit for Partial Discharge Measurement Figure 3 Alternative Test Circuit for Partial Discharge Measurement Figure 4 Example of Balanced Test Circuit for Partial Discharge Measurement Figure 5 Example of Calibration Circuit for Partial Discharge Measurement Figure 6 Transmitted Overvoltages Measurement: Test Circuit and GIS Test Set-up Figure 7 Transmitted Overvoltages Measurement: General Test Set-up Figure C Figure C Figure C Figure C Figure C Figure C Figure D.1 Altitude Correction Factors Table 1 Temperature Categories Table 2 Limits of Temperature Rise of the Windings Table 3 Rated Insulation Levels for Transformer Primary Windings having Highest Voltage for Equipment Um < 300 kV Table 4 Rated Insulation Levels for Transformer Primary Windings having Highest Voltage for Equipment Um ≥ 300 kV Table 5 Power Frequency Withstand Voltages for Transformer Primary Windings having Highest Voltage for Equipment Um ≥ 300 kV Table 6 Partial Discharge Test Voltages and Permissible Levels Table 7 Creepage Distances Table 8 Transmitted Overvoltage Limits Table 9 Static Withstand Test Loads Table 10 Modalities of Application of Test Loads to be Applied to the Primary Terminals Table 11 Markings of Terminals Table 12 Limits of Current Error and Phase Displacement for Measuring Current Transformers (Classes from 0.1 to 1) Table 13 Limits of Current Error and Phase Displacement for Measuring Current Transformers for Special Application Table 14 Limits of Current Error for Measuring Current Transformers (Classes 3 and 5) Table 15 Limits of Error for Protective Current Transformers Table 16 Limits of Error for Class PR Protective Current Transformers Table A.1 Comparison of Chapter and Article Numbers of This Standard to Those of IEC 60044-1: Table A.2 Comparison of Figure and Table Numbers of This Standard to Those of IEC 60044-1: Table B.1 Technical Differences between This Standard and IEC 60044-1:2003 and Their Reasons Table D.1 Rated Insulation Levels for Transformer Primary Windings Having Highest Voltage for Equipment Um < 300 kV Table D.2 Rated Insulation Levels for Transformer Primary Windings Having Highest Voltage for Equipment Um ≥ 300 kV Table D.3 Power Frequency Withstand Voltages for Transformer Primary Windings Having Highest Voltage for Equipment Um ≥ 300 kV