GB/T 12706.1-2020Power 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) (English PDF)

Foreword

GB/T 12706 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) is divided into 4 parts.

---Part 1.Cables for Rated Voltage of 1 kV (Um = 1.2 kV) and 3 kV (Um = 3.6 kV);

---Part 2.Cables for Rated Voltages from 6 kV (Um = 7.2 kV) up to 30 kV (Um = 36

kV);

---Part 3.Cables for Rated Voltages of 35 kV (Um = 40.5 kV);

---Part 4.Test Requirements on Accessories for Cables with Rated Voltages from

6 kV (Um = 7.2 kV) up to 35 kV (Um = 40.5 kV).

This is Part 1 of GB/T 12706.

This Part serves as a replacement of GB/T 12706.1-2008 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).

In comparison with GB/T 12706.1-2008, apart from editorial modifications, this Part

has the following main technical changes.

---The requirements for materials of inner coverings are modified (see 7.2.2; 7.1.2

of Version 2008);

---The stipulations of extruded inner coverings are modified (see 7.2.3 and Table

9; 7.1.3 and Table 8 of Version 2008);

---The stipulations of lapped inner coverings are modified (see 7.2.4; 7.1.4 of

Version 2008);

---The stipulations of copper tape screen overlap rate are modified (see 9.2.3;

17 and Table 22 of Version 2008);

---The calculation formula of fictitious diameter of cable core of three-core cable

with a small cross-section is added (see A.2.3);

---The rounding-off rules for specified values are added (see B.3);

---The measurement and calculation of the overlap rate and clearance rate of

lapped tape are added (see Appendix C);

---The requirements for the delivery length and marking of finished cables are

added (see E.3.2 and E.3.3);

---The recommended ambient temperature for the installation of halogen-free

flame-retardant sheathed cable is added (see E.4.1).

This Part uses the re-drafting method in the modification and adoption of IEC 60502-

11 corresponds to Table 10, Table 12 corresponds to Table 11, Table 13

corresponds to Table 12, Table 14 corresponds to Table 17, Table 15

corresponds to Table 22, Table 16 corresponds to Table 13, Table 17

corresponds to Table 14, Table 18 corresponds to Table 15, Table 19

corresponds to Table 18, Table 20 corresponds to Table 19, Table 21

corresponds to Table 16, Table 22 corresponds to Table 20, Table 23

corresponds to Table 21;

---11.1 and 11.2 are deleted;

---16.10, 16.11, 16.12, 18.4 and B.3 are added;

---Chapter 20 is added;

---Appendix C and Appendix E are added, which changes appendix numbers.

Appendix D of this Part corresponds to Appendix C of IEC 60502-1.2009.

In comparison with IEC 60502-1.2004, this Part has technical differences. The main

technical differences and the causes for the differences are as follows.

---In terms of Normative References, this Part makes certain adjustments with

technical differences, so as to adapt to the technical conditions of China. The

adjustments are intensively reflected in Chapter 2 "Normative References". See

the specific adjustments below.

 GB/T 156, which modifies and adopts international standard, is used to

replace IEC 60038.1983 (see 4.1);

 GB/T 2951.11-2008, which equivalently adopts international standard, is

used to replace IEC 60811-1-1.1993 (see 16.5.1, 16.8, 16.12.1, 18.2.2,

18.3.2, 18.5, 18.6, 18.21.1, Table 18 and Table 19);

 GB/T 2951.13-2008, which equivalently adopts international standard, is

used to replace IEC 60811-1-3.1993 (see 18.15, 18.18.1, 18.22.1, 18.24.1,

Table 14, Table 21, Table 22 and Table 23);

 GB/T 2951.21-2008, which equivalently adopts international standard, is

used to replace IEC 60811-2-1.1998 (see 16.9.1, 18.12, 18.14.1, Table 14

and Table 15);

 GB/T 2951.41-2008, which equivalently adopts international standard, is

used to replace IEC 60811-4-1.1985 (see 18.17.1 and Table 22);

 The reference of GB/T 3048.10 is added (see 12.3.3 and 13.1);

 GB/T 3048.13, which modifies and adopts international standard, is used

to replace IEC 60230.1966 (see 14.3 and 17.5.1);

 GB/T 3956, which equivalently adopts international standard, is used to

replace IEC 60228.1978 (see Chapter 5, 9.2.1, 15.2 and 16.4);

 The references of GB/T 6995.3 and GB/T 6995.5 are added (see E.3.3);

 GB/T 7113.2, which modifies and adopts international standard, is used to

replace IEC 60684-2.1987 (see 18.16.6.1 and Table 5);

 The reference of GB/T 8170 is added (see B.3);

 The reference of GB/T 11017.2-2014 is added (see 9.2.2);

 The reference of GB/T 11091 is added (see 9.2.3);

 GB/T 12706.2, which modifies and adopts international standard, is used

to replace IEC 60502-2.1997 (see Chapter 4);

 GB/T 16927.1, which modifies and adopts international standard, is used

to replace IEC 60060-1.1989 (see 14.3);

 GB/T 17650.1, which equivalently adopts international standard, is used to

replace IEC 60754-1.1994 (see Table 5 and 18.16.4);

 GB/T 17650.2, which equivalently adopts international standard, is used to

replace IEC 60754-2.1991 (see Table 5 and 18.16.5);

 GB/T 18380.11, GB/T 18380.12 and GB/T 18380.13, which equivalently

adopt international standard, are used to replace IEC 60332-1.1993 (see

18.16.1);

 The references of GB/T 18380.33, GB/T 18380.34 and GB/T 18380.36 are

added (see 18.16.2);

 The reference of GB/T 19666 is added (see E.1.3);

 The reference of JB/T 8137 (all parts) is added (see E.3.4.1);

 JB/T 8996, whose consistent correspondence with international standard

is non-equivalent, is used to replace IEC 60183.1984 (see 4.1);

 The non-normative reference of IEC 60724 is brought into Bibliography;

 IEC 61034-2.1997 and ISO 48.1994 are modified into undated references.

---In order to adapt to the technical requirements of China, the term and definition

of fictitious value is deleted (see Chapter 3);

---In order to adapt to the technical requirements of China, the stipulations (see

1 Scope

This Part of GB/T 12706 specifies the structure, dimensions and test requirements for

power cables with extruded insulation for rated voltage of 1 kV (Um = 1.2 kV) and 3 kV

(Um = 3.6 kV).

2 Normative References

The following documents are indispensable to the application of this document. In

terms of references with a specified date, only versions with a specified date are

applicable to this document. In terms of references without a specified date, the latest

version (including all the modifications) is applicable to this document.

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)

3 Terms and Definitions

The following terms and definitions are applicable to this document.

Sample tests are tests carried out by the manufacturer on finished cable specimens or

some parts taken from finished cables at a specified frequency to check whether the

cables meet the specified requirements.

4 Voltage Marking and Materials

For example, under normal operating conditions, if the cable is directly buried in the

ground, in accordance with the maximum conductor temperature specified in Table 3,

the cable is operated under continuous load (100% load factor), after a certain time,

the thermal resistance coefficient of the soil around the cable might exceed its original

value as a result of the drying-out process.

5 Conductors

The conductors shall be Type 1 or Type 2 or Type 5 plain or metal-coated annealed

copper conductors, type 1 or type 2 aluminum or aluminum alloy conductors that

comply with GB/T 3956.

6 Insulation

The nominal insulation thicknesses are shown in Table 6, Table 7 and Table 8.The

thickness of any isolation layer shall not be included in the insulation thickness.

7 Cores, Inner Coverings and Fillers of Multi-core Cables

The materials used for the inner coverings and fillers shall be suitable for the operating

temperature of the cable and compatible with the cable insulating material. Except for

longitudinal water-blocking cables, the inner coverings and fillers shall adopt non-

hygroscopic materials.

8 Metallic Layers for Single-core or Multi-core Cables

This Part includes the following types of metallic layer.

9 Metallic Screen

The metallic screen shall be composed of one or more metallic tapes, braids, or a

concentric layer of metal wires, or a combination of metal wires and tapes.

The metallic screen may also be metallic sheath, or metallic amor layer that complies

with the stipulations of 9.2.

The soft copper tapes, as the raw material of the screen, shall be copper tapes that

comply with the stipulations of GB/T 11091.

10 Concentric Conductor

The dimensions, physical properties and resistance requirements of the concentric

conductors shall comply with the stipulations of 9.2.

If a concentric conductor structure is adopted, the inner covering of multi-core cables

shall be covered with a concentric conductor layer.

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