GL Technology Installation of OPGW Manual (1-1)
1. Frequently-used installation of OPGW
The method of OPGW Cable installation is tension payoff. Tension payoff can make OPGW receive constant tension in the whole payoff process through payoff system which remains enough spare from obstacles and other objects and avoid friction, so as to protect OPGW. And it also can lighten physical labor and
improve the speed of the project.
2. Laying preparation of OPGW
2.1 Dealing with pay-off channel, obstacles, cross agreement and safeguard procedures We usually carried out with power line construction according to
relevant provisions in “Overhead Transmission Lines Design Technology procedures” and “Power Line Construction and Acceptance Interim Technical Specifications”. Before construction, pay-off channels would be made out in the areas where lines go through to ensure unblocked transport. Find out obstacles, specific location of cross, make cross agreement, build protection frame measures in advance for crossing railways, expressways, rivers, uninterrupted lines, communications radio lines, streets, fruit-bearing forest and so on, try hard not to damage surrounding crops. When operated crossing other liners, we should avoid any touch and pulled by load-carrying insulation rope so as to avoid short-circuit accident. Streets and bridges that tensionstringing equipment passes must be prospected and should be repaired when necessary.
2.2 Arrangement of traction site and tension site
(1) Tension site usually choose a field of width: 10m and length: 25m and should be convenient for the storage and transportation for tension machine, cable reels and other materials and facilities. Traction site can be chosen as the tension site.
(2) Tension site and traction site should be located at the outside of the tension tower of two ends of the erection section and should be in the line direction. It can also be chosen in the inner side when confined to geography. If traction site can’t be placed in the line direction, we can use a pulley with large diameter, please be careful not to slide during pay-off.
(3) The distance between traction machine and tension machine to the first fundamental tower should be at least 3 times the height of the tower, and the distance between tension machine and the spool of pay-off stand shouldn’t be less than 5m.
(4) The force direction of traction machine wheel, tension machine pulley, cable pay-off stand, pulling rope and pulling rope drum should be perpendicular to the axis, and avoid direction change in the pulley.
(5) The traction machine, tension machine and cable pay-off stand should be anchored according to the
2.3 Hang the pay-off pulley
Hang a pulley that meets dimensional requirement on each tower according to OPGW construction technical requirements. First fundamental tower, corner tower that close to traction site and tension site and the tower that makes cable can’t meet the requirement of pulley’s envelope angle for the large height difference, we should hang a pulley whose tank bottom diameter is more than 800mm (or can use combined type pulley block with a diameter of 600mm).
For the pay-off in corner tower, during pay-off period, the pulley has a period that leans from vertical direction to corner inside, this period is unstable, especially the impact force of anti-torsion whip from the pulley ad it is easily to cause the cable leaping from the groove which leads to thread jamming. In order to avoid this, we can put the pulley to pre-leaning inside.
2.4 Laying and levitation of pulling rope
Pulling rope is laid in section by manual work according to their drum length, and then connected by bending resistance connector and this process must have a responsible specialist; after this, to check whether the fair line of the pulling rope is intact. Before using pulling rope connector, check whether there is fracture, formation and it is strictly prohibited to use nonconforming product. After the laying of pulling rope is finished, it should be raised up to the groove of pay-off pulley.
2.5 Traction end connection
During pay-off period, fibers in the OPGW can easily be effected and damaged for extra torsion of OPGW, so the traction end need to be made well to make sure OPGW won’t have torsion during pay-off period. The end of the cable can’t be directly wrapped on the tension machine after being pulled from the
drum; we should firstly use a tightrope to wrap on the tension machine and then draw the cable to avoid man-made cable torsion. The connection method of cable with pulling rope after the cable passes through tension machine is: cable—traction net pipe—bending resistance connector–anti-torsion whip (optional)—spiral connector—traction rope.