DL/T 763-2013 English PDF (DLT763-2013)

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DL/T 763-2013: Technical requirements for overhead line helical fittings
DL/T 763-2013
DL
POWER INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
ICS 27.100
K 47
Filing No.: 40019-2013
Replacing DL/T 763-2001
Technical requirements for overhead line helical fittings
ISSUED ON: MARCH 07, 2013
IMPLEMENTED ON: AUGUST 01, 2013
Issued by: National Energy Administration
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Terms and definitions ... 5
4 Model and marking ... 6
5 Structure type ... 8
6 Technical conditions ... 9
7 Test method ... 11
8 Acceptance rules ... 19
9 Labeling, packaging, transportation, storage ... 21
Appendix A (Normative) Breeze vibration fatigue test ... 22
Appendix B (Normative) Waving fatigue test ... 24
Technical requirements for overhead line helical fittings
1 Scope
This standard specifies the types and technical conditions of overhead line helical
fittings.
This standard applies to helical fittings, such as suspension clamps, tension clamps,
connecting fittings, protective fittings, which are installed on overhead lines in a pre-
twisted manner.
2 Normative references
The following documents are essential to the application of this document. For the dated
documents, only the versions with the dates indicated are applicable to this document;
for the undated documents, only the latest version (including all the amendments) is
applicable to this standard.
GB/T 528 Rubber, vulcanized or thermoplastic - Determination of tensile stress-
strain properties
GB/T 1173 Casting aluminium alloys
GB/T 1179 Round wire concentric lay overhead electrical stranded conductors
GB/T 2314 General technical requirements for electric power fittings
GB/T 2317.1 Test method for electric power fittings - Part 1: Mechanical tests
GB/T 2317.2 Test method for electric power fittings - Part 2: Corona and RIV tests
for electric power fittings
GB/T 2317.3 Test method for electric power fittings - Part 3: Heat cycle tests for
electric power fittings
GB/T 2317.4 Test method for electric power fittings - Part 4: Acceptance inspection
for electric power fittings
GB/T 2479 Conventional abrasive - White fused alumina
GB/T 10125 Corrosion tests in artificial atmospheres - Salt spray tests
GB/T 11352 Carbon steel castings for general engineering purpose
GB/T 15115 Die casting aluminum alloys
GB/T 17937 Aluminium-clad steel wires for electrical purposes
GB/T 23308 Aluminium-magnesium-silicon alloy wire for overhead line conductors
DL/T 683 Nomenclature for fitting model
DL/T 758 Splicing fittings
DL/T 766 Technical requirements and tests for helical fittings of OPGW
DL/T 767 Technical requirements and tests for helical fittings of ADSS
DL/T 768.4 Manufacture quality specification for electric power fittings spheroidal
graphite iron castings
DL/T 768.7 Manufacture quality specification for electric power fittings hot dip
galvanized coatings on fabricated iron and steel articles
DL/T 788 All dielectric self-supporting optical fiber cable
DL/T 832 Optical fiber composite overhead ground wires
DL/T 1069 Repair guideline of conductor and earth wire for overhead transmission
line
DL/T 1098 Requirements and tests for overhead line spacers
DL/T 1099 Technical requirements and tests for damper
YB/T 4222 Coated steel wire for overhead line helical fittings
3 Terms and definitions
The following terms and definitions apply to this standard.
3.1
Helical fittings
Fittings consisting of pre-twisted helical wires or non-metallic wires and related
accessories.
3.2
Valid length
Figure 2 -- Schematic diagram of the typical structure of commonly used helical
fittings
6 Technical conditions
6.1 General requirements
6.1.1 The general technical conditions of helical fittings shall comply with the
provisions of GB/T 2314. It shall be manufactured according to the drawings which are
approved by the prescribed procedures.
6.1.2 Dimensions and tolerances:
a) The size of the fittings shall meet the requirements of the design drawings.
b) The effective length of the helical wire of the helical tension clamp should not be
less than 5 pitches.
c) The single wire diameter tolerance for manufacturing helical wires shall comply
with the provisions of GB/T 17937, GB/T 23308, YB/T 4222.
6.1.3 Appearance of helical wire:
a) The end of the helical wire is generally round or hemispherical. If there is an anti-
corona requirement, the end of the helical wire should be duckbill-shaped.
b) The surface of the helical wire shall be smooth and free from defects, such as
cracks, folds, scars.
6.1.4 Helical direction of helical wire: The outer helical wire of the helical fittings shall
be in the same direction as the outer layer of the twisted wire, generally right-handed.
The rotation direction of the helical wire in the inner layer of the tension clamp, for
OPGW, shall be opposite to that of the outer layer of OPGW.
6.1.5 Material of helical wire:
a) The material of the helical wire shall meet the design requirements.
b) The tensile strength of aluminum alloy wire shall not be lower than 340 MPa; the
tensile strength of aluminum-clad steel wire shall not be lower than 1100 MPa.
c) The mechanical properties and galvanizing quality of the galvanized steel wire,
which is used for helical wire, shall comply with the provisions of YB/T 4222.
d) The helical wire material, which is used for helical tension clamps for insulated
cables, shall be made of metal wires, whose strength is higher than that of the
insulated cable core.
6.1.6 The white corundum, which is used in manufacturing, shall comply with the
provisions of GB/T 2479.
6.1.7 Components and accessories, which are made of ferrous metals, are generally
treated with hot-dip galvanizing for anti-corrosion treatment.
6.1.8 If there are other special requirements, they shall be determined, through
negotiation between the supplier and the purchaser.
6.2 Suspension clamps
6.2.1 The sum (α) of the double-sided hanging angles of single-hanger clamp shall not
be less than 30°; the sum (α) of double-sided hanging angles of double-hanger clamps
shall not be less than 60°.
6.2.2 The cast aluminum alloy, which is used for the main body of the suspension clamp,
shall meet the requirements of GB/T 1173 or GB/T 15115.
6.2.3 The synthetic rubber parts, in the suspension clamps, shall have good anti-aging
properties, anti-ozone, anti-ultraviolet, anti-air pollution capabilities. The performance
of the rubber components shall meet the requirements in 7.8 of DL/T 1098.
6.2.4 Suspension clamps shall meet the requirements of vertical load and grip. The
clamping force of the suspension wire shall meet the requirements of GB/T 2314, which
shall not be less than 14% ~ 28% of the rated breaking force of the cable.
6.2.5 When the horizontal unbalanced load exceeds the design value, the clamp shall
slide.
6.3 Tension clamp
6.3.1 When steel strands are connected to ground rods through helical tension clamps,
it shall be considered to set up the length adjustment device of the pull wires and the
anti-theft measures of helical wires.
6.3.2 Grip of tension clamps:
a) The grip of helical tension clamps, which are used for conductors and ground
wires, optical fiber composite overhead ground wires, optical fiber composite
phase wires, etc., shall not be less than 95% of the rated breaking force of the
cables.
b) The grip of the helical tension clamps, which a...