Power cables with extruded insulation and their accessories for rated voltages from 1 kV (Um=1.2 kV) up to 35 kV (Um=40.5 kV)—Part 1: Cables for rated voltage of 1 kV(Um=1.2 kV)and 3 kV(Um=3.6 kV)
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GB/T 12706 consists of 4 parts under the general title Power cables with extruded insulation and their accessories for rated voltages from 1kV (Um=1.2kV) up to 35kV (Um=40.5kV):
——Part 1: Cables for rated voltage of 1kV (Um=1.2kV) and 3kV (Um=3.6kV);
——Part 2: Cables for rated voltages from 6kV (Um=7.2kV) up to 30kV (Um=36kV);
——Part 3: Cables for rated voltages of 35kV (Um= 40.5kV);
——Part 4: Test requirements on accessories for cables with rated voltages from 6kV (Um=7.2kV) up to 35kV (Um=40.5kV).
This is Part 1 of GB/T 12706.
This part replaces GB/T 12706.1-2008 Power cables with extruded insulation and their accessories for rated voltages from 1kV (Um=1.2kV) up to 35kV (Um=40.5kV) - Part 1: Cables for rated voltage of 1kV (Um=1.2kV) and 3kV (Um=3.6kV).
In addition to editorial changes, the following main technical changes have been made with respect to GB/T 12706.1-2008:
——The requirements for inner covering materials are modified (see 7.2.2; 7.1.2 of Edition 2008);
——The requirements for extruded inner coverings are modified (see 7.2.3 and Table 9; 7.1.3 and Table 8 of Edition 2008);
——The requirements for lapped inner coverings are modified (see 7.2.4; 7.1.4 of Edition 2008);
——The requirements for overlap rate of copper strip screen are modified (see 9.2.3; 9.2.3 of Edition 2008);
——The calculation formula for nominal thickness of lead sheath are modified (see Clause 11; Clause 11 of Edition 2008);
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——The requirements for armouring materials are modified (see 12.2; 12.2 of Edition 2008);
——The requirements for the nominal diameter of thick round metal wires and those for the nominal thickness of separation sheath or inner covering under armour are added (see 12.4, Table 10 and 12.6);
——The requirements for thickness of oversheath are modified (see 13.3; 13.3 of Edition 2008);
——The requirements for d.c. resistance of aluminium alloy conductor are added (see 15.2);
——The measurement requirements for non-metal sheath are modified (see 16.5; 16.5 of Edition 2008);
——The measurement of overlap rate and gap rate of lapped tapes is added (see 16.10 and 16.11);
——The thickness measurement of lapped inner covering and (or) lapped bedding is added (see 16.12 and 18.4);
——The measurement requirements for non-metal sheath are modified (see 18.3; 18.2 of Edition 2008);
——The requirements for pressure test at high temperature are modified (see 18.9.1; 18.7.1 of Edition 2008);
——The requirements for flame spread test on single cables are modified (see 18.16.1; 18.14.1 of Edition 2008);
——The requirements for flame spread test on bunched cables are modified (see 18.16.2; 18.14.2 of Edition 2008);
——The requirements for smoke density test are modified (see 18.16.3; 18.14.3 of Edition 2008);
——The applicable objects of the measurement of carbon black content of black PE oversheaths are modified (see 18.17.1; 18.15.1 of Edition 2008);
——The time under load of hot set test is deleted (see Tables 14 and 15; Tables 17 and 22 of Edition 2008);
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——The calculation formula for the fictitious diameter of core of three-core cable with one conductor with reduced cross-section is added (see A.2.3);
——The rounding rules for specified values are added (see B.3);
——The measurement and calculation of overlap rate and gap rate of lapped materials are added (see Annex C);
——The requirements for delivery length and marking of finished cable are added (see E.3.2 and E.3.3);
——The recommendation of ambient temperature during installation of halogen-free flame-retardant sheathed cables is added (see E.4.1).
This part has been redrafted and modified in relation to IEC 60502-1:2004 Power cables with extruded insulation and their accessories for rated voltages from 1kV (Um=1.2kV) up to 30kV (Um=36kV) - Part 1: Cables for rated voltage of 1kV (Um=1.2kV) and 3kV (Um=3.6kV). At the same time, the content of AMD 1:2009 CSV is included, and is marked with perpendicular double lines(||) in the outside page margin of the provisions concerned.
The following main structural changes have been made with respect to IEC 60502-1:2004:
——The hanging paragraphs are adjusted and 7.1, 16.6.1, 17.1, 18.1, 18.19.1 and D.2.1 are added according to the requirements of GB/T 1.1-2009, with the subsequent subclause numbers increased accordingly;
——The table numbers are adjusted in the order of references. Starting from Table 5, the correspondence between tables in this part and those in IEC 60502-1:2009 is Table 5 corresponding to Table 23, Table 6 to Table 5, Table 7 to Table 6, Table 8 to Table 7, Table 9 to Table 8, Table 10 to Table 9, Table 11 to Table 10, Table 12 to Table 11, Table 13 to Table 12, Table 14 to Table 17, Table 15 to Table 22, Table 16 to Table 13, Table 17 to Table 14, Table 18 to Table 15, Table 19 to Table 18, Table 20 to 19, Table 21 to Table 16, Table 22 to Table 20, and Table 23 to Table 21;
——11.1 and 11.12 are deleted;
——16.10, 16.11, 16.12, 18.4 and B.3 are added;
——Clause 20 is added;
——Annexes C and E are added, so that the annex numbers are changed. Annex D of this part corresponds to Annex C of IEC 60502-1:2009.
The main technical differences of this part from IEC 60502-1:2004 and their justifications are as follows:
——The adjustment on technical differences has been made on “Normative references” of this part to meet the technical specification in China; the adjustment situations are embodied in a concentrated way in Clause 2 - "Normative references" and the specific adjustments are as follows:
? IEC 60038:1983 is replaced by GB/T 156 which is modified in relation to the international standard (see 4.1);
? IEC 60811-1-1:1993 is replaced by GB/T 2951.11-2008 which is identical to the international standard (see 16.5.1, 16.8, 16.12.1, 18.2.2, 18.3.2, 18.5, 18.6, 18.21.1, and Tables 18 and 19);
? IEC 60811-1-3:1993 is replaced by GB/T 2951.13-2008 which is identical to the international standard (see 18.15, 18.18.1, 18.22.1, 18.24.1, and Tables 14, 21, 22 and 23);
? IEC 60811-2-1:1998 is replaced by GB/T 2951.21-2008 which is identical to the international standard (see 16.9.1, 18.12, 18.14.1, and Tables 14 and 15);
? IEC 60811-4-1:1985 is replaced by GB/T 2951.41-2008 which is identical to the international standard (see 18.17.1 and Table 22);
? GB/T 3048.10 is added for reference (see 12.3.3 and 13.1);
? IEC 60230:1966 is replaced by GB/T 3048.13 which is modified in relation to the international standard (see 14.3 and 17.5.1);
? IEC 60228:1978 is replaced by GB/T 3956 which is identical is the international standard (see Clause 5, 9.2.1, 15.2 and 16.4);
? GB/T 6995.3 and GB/T 6995.5 are added for reference (see E.3.3);
? IEC 60684-2:1987 is replaced by GB/T 7113.2 which is modified in relation to the international standard (see 18.16.6.1 and Table 5);
? GB/T 8170 is added for reference (see B.3);
? GB/T 11017.2-2014 is added (see 9.2.2);
? GB/T 11091 is added for reference (see 9.2.3);
? IEC 60502-2:1997 is replaced by GB/T 12706.2 which is modified in relation to the international standard (see Clause 4);
? IEC 60060-1:1989 is replaced by GB/T 16927.1 which is modified in relation to the international standard (see 14.3);
? IEC 60754-1:1994 is replaced by GB/T 17650.1 which is identical to the international standard (see Table 5 and 18.16.4);
? IEC 60754-2:1991 is replaced by GB/T 17650.2 which is identical to the international standard (see Table 5 and 18.16.5);
? IEC 60332-1:1993 is replaced by GB/T 18380.11, GB/T 18380.12 and GB/T 18380.13 which are identical to the international standard (see 18.16.1);
? GB/T 18380.33, GB/T 18380.34 and GB/T 18380.36 are added for reference (see 18.16.2);
? GB/T 19666 is added for reference (see E.1.3);
? JB/T 8137 (all parts) is added for reference (see E.3.4.1);
? IEC 60183:1984 is replaced by JB/T 8996 which is not equivalent to the international standard (see 4.1);
? The non-normative reference IEC 60724 is included in the Bibliography;
? IEC 61034-2:1997 and ISO 48:1994 are changed to undated references.
——In order to meet the technical requirements of China, the term and definition of “fictitious value” are deleted (see Clause 3);
——In order to meet the technical requirements of China, the thickness requirements (see 7.2.3 and 7.2.4) and technical requirements (see 12.7, 16.5 and 18.3) for extruded and lapped inner coverings are modified;
——The thickness requirements for other metal sheaths are deleted (see Clause 11);
——In order to meet the technical requirements of China, the measurement of overlap rate (see 16.10) and that of gap rate (see 16.11) of lapped materials are added;
——In order to meet the technical requirements of China, the measurement of total thickness of lapped inner covering and (or) lapped bedding (see 16.12) and their technical requirements (see 18.4) are added;
——In order to clarify the requirements of copper strip materials for cables, the requirements of copper raw materials are added (see 9.2.3);
——To ensure the quality of extruded separation sheath and oversheath, the requirements for spark test of extruded separation sheath (see 12.3.3) and those for spark test of oversheath (see 13.1) are added;
——In order to meet the technical requirements of China, the requirements for the diameter of thick round metal wire and those for the thickness of separation sheath or inner covering under armour are added (see 12.4, Table 10 and 12.6);
——In order to meet the technical requirements of China, the d.c. resistance requirements of aluminium alloy conductors are added (see 15.2);
——In order to meet the technical requirements of China, the application scope and requirements of fire tests (see 18.16.1 and 18.16.2) and the applicable objects of carbon black test (see 18.17.1) are modified;
——In order to improve the domestic technical requirements for power cables, supplementary items for cable products are added (see Clause 20 and Annex E);
——The calculation formulae for the fictitious diameter of core of three-core cables with one conductor with reduced cross-section, five-core cables with one conductor with reduced cross-section, and five-core cables with two conductors with reduced cross-section are added (see A.2.3); the rounding rules of specified values are added (see B.3) to meet the technical requirements of China;
——In order to define the overlap rate and gap rate, the measurement and calculation of overlap rate and gap rate of lapped materials are added (see Annex C).
The following editorial changes have been made in this part:
——In order to adapt to China's technical standard system, the standard name is changed to Power cables with extruded insulation and their accessories for rated voltages from 1kV (Um=1.2kV) up to 35kV (Um=40.5kV) - Part 1: Cables for rated voltage of 1kV (Um=1.2kV) and 3kV (Um=3.6kV);
——The “Bibliography” is added.
This part was proposed by the China Electrical Equipment Industrial Association.
This part is under the jurisdiction of SAC/TC 213 National Technical Committee on Wires and Cables of Standardization Administration of China.
The previous editions of this part are as follows:
——GB 12706.1-1991, GB/T 12706.1-2002 and GB/T 12706.1-2008;
——GB 12706.2-1991 and GB 12706.3-1991.
Power cables with extruded insulation and their accessories for rated voltages from 1kV (Um=1.2kV) up to 35kV (Um=40.5kV) -
Part 1: Cables for rated voltage of 1kV (Um=1.2kV) and 3kV (Um=3.6kV)
1 Scope
This part of GB/T 12706 specifies the construction, dimensions and test requirements of power cables with extruded insulation for rated voltages of 1kV (Um=1.2kV) and 3kV (Um=3.6kV).
This part is applicable to the power cables with extruded insulation for rated voltages of 1kV (Um=1.2kV) and 3kV (Um=3.6kV) for fixed installations such as distribution networks or industrial installations.
Cables for special installation and service conditions are not included, for example cables for overhead networks, the mining industry, nuclear power plants (in and around the containment area), submarine use or shipboard application.
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 156 Standard voltages (GB/T 156-2017, IEC 60038:2009, MOD)
GB/T 2951.11-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 11: Methods for general application - Measurement of thickness and overall dimensions - Tests for determining the mechanical properties (IEC 60811-1-1:2001, IDT)
GB/T 2951.12-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 12: Methods for general application - Thermal ageing methods (IEC 60811-1-2:1985, IDT)
GB/T 2951.13-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 13: Methods for general application - Measurement for determining the density - Water absorption tests - Shrinkage test (IEC 60811-1-3:2001, IDT)
GB/T 2951.14-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 14: Methods for general application - Test at low temperature (IEC 60811-1-4:1985, IDT)
GB/T 2951.21-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 21: Methods specific to elastomeric compounds - Ozone resistance, hot set and mineral oil immersion tests (IEC 60811-2-1:2001, IDT)
GB/T 2951.31-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 31: Methods specific to PVC compounds - Pressure test at high temperature - Test for resistance to cracking (IEC 60811-3-1:1985, IDT)
GB/T 2951.32-2008 Common test methods for insulating and sheathing materials of electric cables - Part 32: Methods specific to PVC compounds - Loss of mass test - Thermal stability test (IEC 60811-3-2:1985, IDT)
GB/T 2951.41-2008 Common test methods for insulating and sheathing materials of electric and optical cables - Part 41: Methods specific to polyethylene and polypropylene compounds - Resistance to environmental stress cracking - Measurement of the melt flow index - Carbon black and/or mineral filler content measurement in polyethylene by direct combustion - Measurement of carbon black content by thermo gravimetric analysis (TGA) - Assessment of carbon black dispersion in polyethylene using a microscope (IEC 60811-4-1:2004, IDT)
GB/T 3048.10 Test methods for electrical properties of electric cables and wires - Part 10: Spark test of extruded protective sheaths
GB/T 3048.13 Test methods for electrical properties of electric cables and wires - Part 13: Impulse voltage test (GB/T 3048.13-2007, IEC 60230:1966, IEC 60060-1:1989, MOD)
GB/T 3956 Conductors of insulated cables (GB/T 3956-2008, IEC 60228:2004, IDT)
GB/T 6995.3 Markings for electric cables and wires - Part 3: Identifications of cables and wires
GB/T 6995.5 Markings for electric wires and cables - Part 5: Identifications of insulated cores of power cables
GB/T 7113.2 Flexible insulating sleeving - Part 2: Methods of test (GB/T 7113.2-2014, IEC 60684-2:2003, MOD)
GB/T 8170 Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 11017.2-2014 Power cables with cross-linked polyethylene insulation and their accessories for rated voltage of 110kV (Um=126kV) - Part 2: Power cables
GB/T 11091 Copper strip for cables
GB/T 12706.2 Power cables with extruded insulation and their accessories for rated voltages from 1kV (Um=1.2kV) up to 35kV (Um=40.5kV) - Part 2: Cables for rated voltages from 6kV (Um=7.2kV) up to 30kV (Um=36kV) (GB/T 12706.2-2020, IEC 60502-2:2014, MOD)
GB/T 16927.1 High-voltage test techniques - Part 1: General definitions and test requirements (GB/T 16927.1-2011, IEC 60060-1:2010, MOD)
GB/T 17650.1 Test on gases evolved during combustion of materials from cables - Part 1: Determination of the amount of halogen acid gas (GB/T 17650.1-1998, IEC 60754-1:1994, IDT)
GB/T 17650.2 Test on gases evolved during combustion of materials from cables - Part 2: Determination of degree of acidity of gases by measuring pH and conductivity (GB/T 17650.2-1998, IEC 60754-2:1991, IDT)
GB/T 18380.11 Tests on electric and optical fibre cables under fire conditions - Part 11: Test for vertical flame propagation for a single insulated wire or cable - Apparatus (GB/T 18380.11-2008, IEC 60332-1-1:2004, IDT)
GB/T 18380.12 Tests on electric and optical fibre cables under fire conditions - Part 12: Test for vertical flame propagation for a single insulated wire or cable - Procedure for 1kW pre-mixed flame (GB/T 18380.12-2008, IEC 60332-1-2:2004, IDT)
GB/T 18380.13 Tests on electric and optical fibre cables under fire conditions - Part 13: Test for vertical flame propagation for a single insulated wire or cable - Procedure for determination of flaming droplets/particles (GB/T 18380.13-2008, IEC 60332-1-3:2004, IDT)
GB/T 18380.33 Tests on electric and optical fibre cables under fire conditions - Part 33: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category A (GB/T 18380.33-2008, IEC 60332-3-22:2000, IDT)
GB/T 18380.34 Tests on electric and optical fibre cables under fire conditions - Part 34: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category B (GB/T 18380.34-2008, IEC 60332-3-23:2000, IDT)
GB/T 18380.35 Tests on electric and optical fibre cables under fire conditions - Part 35: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category C (GB/T 18380.35-2008, IEC 60332-3-24:2000, IDT)
GB/T 18380.36 Tests on electric and optical fibre cables under fire conditions - Part 36: Test for vertical flame spread of vertically-mounted bunched wires or cables - Category D (GB/T 18380.36-2008, IEC 60332-3-25:2000, IDT)
GB/T 19666 Flame retardant and fire resistant wires and cables
JB/T 8137 (all parts) Delivery drums for wires and cables
JB/T 8996 Guide to the selection of high-voltage cables (JB/T 8996-2014, IEC 60183:1984, NEQ)
ISO 48 Rubber, vulcanized or thermoplastic - Determination of hardness (hardness between 10 IRHD and 100 IRHD)
IEC 61034-2 Measurement of smoke density of cables burning under defined conditions - Part 2: Test procedure and requirements
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 Terms concerning dimensional values
3.1.1
nominal value
value by which a quantity is designated and which is often used in tables
Note: Usually, in this part, nominal values give rise to values to be checked by measurements taking into account specified tolerances.
3.1.2
approximate value
value which is neither guaranteed nor checked
Note: It is used, for example, for the calculation of other dimensional values.
3.1.3
median value
when several test results have been obtained and ordered in an increasing (or decreasing) succession, the median value is the middle value if the number of available values is odd, and the mean of the two middle values if the number is even
3.2 Definitions concerning the tests
3.2.1
routine tests
tests made by the manufacturer on each manufactured length of cable to check that each length meets the specified requirements
3.2.2
sample tests
tests made by the manufacturer on samples of completed cable or components taken from a completed cable, at a specified frequency, so as to verify that the finished product meets the specified requirements
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3.2.3
type tests
tests made before supplying, on a general commercial basis, a type of cable covered by this part, in order to demonstrate satisfactory performance characteristics to meet the intended application
Note: These tests are of such a nature that, after they have been made, they need not be repeated, unless changes are made in the cable materials or design or manufacturing process which might change the performance characteristics.
3.2.4
electrical tests after installation
tests made to demonstrate the integrity of the cable and its accessories as installed
4 Voltage designations and materials
4.1 Rated voltages
The rated voltages U0/U(Um) of the cables considered in this part are 0.6//1(1.2)kV and 1.8/3(3.6)kV.
Note: The voltages given above are the correct designations although in some countries other designations are used, e.g. 1.7/3kV or 1.9/3.3kV instead of 1.8/3kV.
In the voltage designation of cables U0/U(Um):
——U0 is the rated power frequency voltage between conductor and earth or metal screen for which the cable is designed;
——U is the rated power frequency voltage between conductors for which the cable is designed;
——Um is the maximum value of the "highest system voltage'' for which the equipment may be used (see GB/T 156).
The rated voltage of the cable shall be suitable for the operating conditions in the system in which the cable is used. To facilitate the selection of the cable, systems are divided into three categories:
——Category A: this category comprises those systems in which any phase conductor that comes in contact with earth or an earth conductor is disconnected from the system within 1min;
Foreword III
1 Scope
2 Normative references
3 Terms and definitions
4 Voltage designations and materials
5 Conductors
6 Insulation
7 Assembly of multicore cables, inner coverings and fillers
8 Metal layers for single-core and multicore cables
9 Metal screen
10 Concentric conductor
11 Lead sheath
13 Oversheath
14 Test conditions
15 Routine tests
16 Sample tests
17 Electrical type tests
18 Non-electrical type tests
19 Electrical tests after installation
20 Supplementary terms for cable products
Table 17 Non-electrical type tests
Annex A (Normative) Fictitious calculation method for determination of dimensions of protective coverings
Annex B (Normative) Rounding of numbers
Annex C (Normative) Measurement and calculation of lapped overlap rate and gap rate
Annex D (Normative) Determination of hardness of HEPR insulations
Annex E (Normative) Supplementary terms of cable products
Bibliography
Figure D.1 Test on surfaces of large radius of curvature
Figure D.2 Test on surfaces of small radius of curvature
Figure E.1 Composition and arrangement sequence of product model
Table 1 Rated voltages U
Table 2 Insulating compounds
Table 3 Maximum conductor temperatures for different types of insulating compound
Table 4 Maximum conductor temperatures for different types of sheathing compound
Table 5 Test method and requirements of halogen free compounds
Table 6 Nominal thickness of PVC/A insulation
Table 7 Nominal thickness of cross-linked polyethylene (XLPE) insulation
Table 8 Nominal thickness of ethylene propylene rubber (EPR) and hard ethylene propylene rubber (HEPR) insulation
Table 9 Thickness of extruded inner covering
Table 10 Nominal diameter of round armour wires
Table 11 Nominal thickness of armour tapes
Table 12 Routine test voltages
Table 13 Number of samples for sample tests
Table 14 Test requirements for particular characteristics of various thermosetting insulating compounds
Table 15 Test requirements for particular characteristics of elastomeric sheathing compound
Table 16 Electrical type test requirements for insulating compounds
Table 17 Non-electrical type tests
Table 18 Test requirements for mechanical characteristics of cable insulation (before and after ageing)
Table 19 Test requirements for mechanical characteristics of sheathing compounds (before and after ageing)
Table 20 Test requirements for particular characteristics for PVC sheathing compounds
Table 21 Test requirements for particular characteristics for PVC insulating compound
Table 22 Test requirements for particular characteristics of PE (thermoplastic polyethylene) sheathing compounds
Table 23 Test requirements for particular characteristics for halogen free sheathing compounds
Table A.1 Fictitious diameter of conductor
Table A.2 Assembly coefficient K for laid-up cores
Table A.3 Increase of diameter for concentric conductors and metal screens
Table A.4 Increase of diameter for additional bedding
Table B.1 Rounded digits of specified values, measured values or their calculated value
Table E.1 Cable models
Table E.2 Recommended nominal cross-sectional area of conductor of neutral wire and protective wire of multi-core cable
Table E.3 Minimum bending radius during cable installation
