3.2.1 Insulating Rope
1.Basic Structure and Function of Insulating Rope
(1)Basic structure
Insulating ropes are mainly made from silk or synthetic fiber,among which silk ropes are most commonly used.Silk is a good electrical insulating material in the dry state.However,silk has a strong hygroscopicity because of the hydrophilicity and fiber porosity of the glue.When silk is used as an insulating material,special care shall be taken to avoid moisture.The tool with insulating rope as the main insulating component is flexible,light,portable and suitable for on-site operation.Fig.3-16 shows the insulating rope.
Fig.3-16 Insulating Rope
(2)Basic function
The insulating rope is widely used in live working,and is one of the most important insulating materials in live working,which can be used as a carrier,climbing tool,lifting rope,connecting sleeve and security rope,etc.In addition,insulating rope or insulating belt can be used to make insulating rope ladder,waist belt,etc.
Insulating ropes commonly used in live working are silk ropes(including raw silk ropes and boiled-off silk ropes)and nylon ropes(including nylon wire ropes and nylon thread ropes).Insulating ropes are used for traction,lifting of objects,temporary pulling of wires,making of ladders and tackle ropes,etc.during live working.Insulating ropes shall not only have high mechanical strength,but also have wear resistance.
2.Classification and Model Specifications of Insulating Ropes
(1)Classification
①According to the material,the insulating rope can be divided into natural fiber insulating rope and synthetic insulating rope.
②According to the electrical properties in the wet state,the insulating rope can be divided into conventional insulating rope and moisture-proof insulating rope.
③According to the mechanical strength,the insulating rope can be divided into conventional strength insulating rope and high strength insulating rope.
④According to the weaving process,the insulating rope can be divided into braided insulating rope,stranded insulating rope and woven insulating rope.
⑤According to the use,the insulating rope can be divided into arc suppression rope,insulating rope noose,insulating safety rope,insulating distance measuring rope and lifting rope.
(2)Model and specification
①Arc suppression rope
The model of the arc suppression rope consists of materials,code numbers and specifications.Example:SCXHS—10×20m
Wherein:SC-silkworm;XHS-arc suppression rope;10-rope diameter 10mm;20mlength 20m.The diameter of the arc suppression rope is 12mm,and the length can be divided into 15m,20m and 30m.
②Insulating rope noose
a.Electrodeless insulating rope noose.The model of the electrodeless insulating rope noose consists of materials,code numbers and specifications.The specifications of the electrodeless insulating rope noose can be made into various rope diameters and lengths as needed.
Example:JCSTW—16×400m
Wherein:JC-nylon filament;ST-noose;W-electrodeless noose;16-rope diameter 16mm;400-length 400m.
b.Two-eye insulating rope noose.The model of the two-eye insulating rope noose consists of materials,code numbers and specifications.The specifications of the two-eye insulating rope noose can be made into various rope diameters and lengths as needed.
Example:JCSTL—16×400m
Wherein:JC-nylon filament;ST-noose;L-two-eye noose;16-rope diameter 16mm;400-length 400m.
③Insulating safety rope
a.Personal insulating safety rope.The model of the personal insulating safety rope consists of materials,code numbers and specifications.The rope diameter of the personal insulating safety rope shall not be less than 14mm,and the length may be various specifications of 2～7m.
Example:JCSTL—14×4m
Wherein:SC-silkworm;RBS-personal safety rope;14-rope diameter 14mm;4-length 4m.(https://www.daowen.com)
b.Conduct insulating safety rope.The model of the conductor insulating safety rope consists of materials,code numbers and specifications.Example:SCDBS—30×4.5m
Wherein:SC-silkworm;DBS-conductor safety rope;30-rope diameter 30mm;4.5-length 4.5m.
See Table 3-4 for the classification and specifications of conductor insulating safety ropes.
Table 3-4 Classification and Specifications of Conductor Insulating Safety Rope
Note:Insulating safety ropes for 500kV four-bundle conductors shall be 2 SCDBS-34×5.5m ropes
④Insulating distance measuring rope
The model of the insulating distance measuring rope consists of materials,code numbers and specifications.Example:SCCS—4×50m
Wherein:SC-silkworm;CS-distance measuring rope;4-rope diameter 4mm;50mlength 50m.The diameter of the insulating distance measuring rope is generally 4-5mm,and the length is 50m.
3.Inspection Items of Insulating Ropes
(1)Insulating rope must be visually checked before use.It is strictly prohibited to wrap insulating rope with metal wire.The twisted synthetic rope strands of all insulating rope tools shall be tightly twisted without looseness or separation.There shall be no fold marks,bulges,reverse strands,cramps and other defects on each strand of the rope and silk threads of each strand.
(2)Before the insulating rope is used,the test certificate shall be checked for validity period.Insulating ropes beyond the validity period cannot be used.
(3)Before the insulating rope is used,the type and diameter of the insulating rope shall be selected according to the working load,and the 2,500V and above tramegger or insulating detector shall be used for segmented insulating detection(electrode width 2cm,interelectrode width 2cm),and the resistance value shall not be less than 700mΩ.Fig.3-17 shows the inspection of insulation performance of the insulating rope.
Fig.3-17 Insulation Performance Inspection of Insulating Ropes
4.Usage of Insulating Ropes
(1)Insulating rope can only be used after passing the test and it is strictly prohibited to use unqualified insulating rope;moisture-proof insulating rope must be selected according to the environmental humidity;dirty insulating rope is strictly prohibited to be used in live working.
(2)Operators of insulating rope shall wear clean and dry gloves.
(3)Insulating rope must be placed on moisture-proof cloth during use to prevent moisture and dirt.
(4)During the use of insulating rope,the safety distance of corresponding voltage level shall be met.Fig.3-18 shows the usage of insulating ropes.
Fig.3-18 Usage of Insulating Ropes
5.Precautions for Storage of Insulating Ropes
Insulating ropes shall be placed in special tool bags,tool cars or special tool cars during transportation to prevent moisture and damage.The insulated tackles shall be stored in a clean and dry special room with good ventilation,infrared light bulbs or dehumidifying equipment.If the storage period exceeds the production date by 12 months,the electrical performance test shall be carried out according to relevant standards.Fig.3-19 shows the storage of the insulating rope.
Fig.3-19 Storage of Insulating Rope
6.Preventive Test of Insulating Rope
The preventive test of the insulating rope includes the following items.
(1)Electrical test.Mainly including the power frequency withstand voltage test and the operating impulse withstand voltage test.The test cycle is 1 year.
(2)Mechanical test.Mainly including the static tensile test.The test cycle is 2 years.