Preliminary preparations for OPGW optical cable construction

OPGW optical cable structure and parameters should be checked each time the OPGW structure and technical parameters are constructed, all OPGW cables pass through the reel, and each reel of optical cable should be installed in the designated interval according to the reel table.

• OPGW warehousing and transportation

OPGW cable reels must be placed vertically during storage and transportation, and horizontal placement is not allowed. There must be anti-movement measures in storage and transportation. In the transportation process, appropriate cranes and forklifts should be used. When hoisting, use a suitable cable to pass through the cable reel shaft hole, and make the cable reel horizontally loaded and unloaded; when using a forklift, the fork feet should be correctly forkped on the side of the cable reel On the upper side, the length of the fork legs should be greater than the width of the cable reel, and it is not allowed to touch the outer layer of the OPGW overhead ground line composite optical cable. During storage and transportation, damage to the cable reel and the packaging of the cable reel should be avoided to ensure that the optical cable is not damaged and the construction is carried out smoothly.

• Opening test
  

Before installation, use OTDR to test the optical fiber in OPGW. The measured data can be compared with the factory data to eliminate the possibility of damage during transportation (because it is not the same instrument, the data will have some slight differences). It can be compared with the measured data after installation to check the changes during the installation process and after the connection (it is best to use the same instrument).

Main tools and equipment for OPGW optical cable construction

A. Cable reel support frame

It is recommended that the cable reel support frame be placed at a distance of about 10 meters from the tension machine, and it must be kept at a distance greater than 5 meters under restricted conditions. Whether it is a movable or fixed cable reel support frame, it must be configured to avoid the OPGW slack on the cable reel caused by free rotation during the wiring process. It is strictly forbidden to directly use the cable reel to release the wire from the support frame without passing through the tension machine.

B. Tension machine

The edge of the tensioner wheel is not allowed to have burrs or depressions, and the wheel groove should be covered with rubber or other suitable materials, and its size should be consistent with the outer diameter of the OPGW. The diameter of the tensioner wheel must be greater than 70 times the diameter of the OPGW and not less than 1200mm.

In order to prevent the so-called "lantern shell" phenomenon when the OPGW outer stranded wire is arched during construction, the stranding direction of the OPGW outer stranded wire must be checked again when winding it on the tension wheel. The left side of the brake end enters the wire, and the left twisted outer layer should enter the right side of the brake end. The tension machine should maintain a constant tension, run continuously and smoothly, and be able to decelerate and restart smoothly at different speeds. OPGW should be wound on the tension wheel at least 6 times and fixed.

C. Tractor

It is best to use a tractor with grooved traction wheels, and the traction speed is required to be stable and variable. In view of the fact that the pay-off tension of the OPGW is usually smaller than the wire tension, it should be checked whether the control range and accuracy of the tractor meet the requirements. The tension should be adjustable and it is better to record the tension change of the traction rope during the pay-off process. If necessary, the traction machine should also be used for tension correction with the tension machine.

D. Communication tools

During the deployment of optical cables, the continuity of construction communication should be maintained, and mobile phones should be prohibited as communication tools

E. Pulley

In order to minimize friction and winding resistance, it is best to use pulleys with high-quality ball bearings. The pulleys should rotate flexibly, have good working conditions and be fully lubricated.

The diameter of the pulley should be as large as possible. In any case, it should not be lower than the minimum bending radius requirement of OPGW. The recommended diameter at the bottom of the pulley groove should meet:

(1) The pulley groove diameter of OPGW input and output towers and corner towers less than 120 degrees should not be less than 800mm;

(2) The diameter of the pulley groove used for OPGW to pass through the tensile tower is not less than 600mm;

(3) The diameter of the pulley groove used for OPGW to pass the linear pole tower is not less than 450mm.

For OPGW with all outer strands or aluminum-clad steel wires, the metal pulley groove needs to be covered with rubber or nylon materials. If the outer strands are aluminum, aluminum alloy, or galvanized steel wires, they can be covered or not covered. In order to ensure that the lower pulley groove will not damage the OPGW stranded wire under any circumstances, the pulley groove must match the OPGW diameter. Usually the groove radius is not less than 0.55 times the OPGW outer diameter, and the groove width should be able to accommodate the cable net sleeve and the anti-torsion device. For the anti-twist whip to pass, the opening angle of the groove side should be between 15 and 20 degrees.