The installation design of OPGW should take into account the coordination with conductor stress, sag and insulation gap, and its load should not exceed the allowable range of use of the existing towers and foundations.Therefore, the characteristic curve of the selected OPGW should be calculated based on its main technical parameters, and the layout, appearance and installation drawings of the junction box, various hardware and accessories should be designed in combination with the actual project.
1. Treatment of initial elongation
The treatment of initial elongation of OPGW can be done by cooling method, that is, checking the aluminum-steel ratio of OPGW and treating its initial elongation by referring to the cooling value of similar conductors or ground wires.
2. Design of anti-vibration measures
Among the hardware used in conjunction with OPGW, the tension clamp is pre-twisted wire type, and the suspension clamp is equipped with pre-twisted wire and rubber pad. These two types of hardware have certain anti-vibration capabilities. In order to further enhance the anti-vibration capability, you can consider installing an anti-vibration hammer, which is generally calculated according to the span:
1、When the span is ≤300M, install one anti-vibration hammer;
2、When the span is >300M, install two anti-vibration hammers.
3. Issues to be noted in the construction and installation of OPGW
The construction and installation of OPGW is different from that of ordinary steel strands. Attention should be paid to preventing damage to the fiber optic cable in order to avoid affecting the performance of the optical fiber in the future. Special considerations should be given to: OPGW torsion, microbend, local radial pressure outside the clamp and contamination of the optical fiber. Therefore, the following effective measures should be taken to solve the problem during the construction phase:
(1) Prevent OPGW torsion
Install a balance hammer and anti-twist device on the walkway and the tension clamp;
Use a special double-groove pulley;
Use a tension wire machine with a double winch;
(2) Prevent and reduce microbends and stress of OPGW
No sharp angles are allowed (control the minimum bending radius of 500mm);
OPGW cable drum diameter should be no less than 1500mm;
Pulley diameter should be more than 25 times the OPGW diameter, and generally not less than 500mm; The inner side of the pulley should have a nylon or rubber liner to prevent scratches on the surface of the OPGW;
Appropriate traction wire and wire-laying hardware;
The coil length of OPGW is 6000M to prevent the number of pulleys;
The line turning angle of continuous pay-off is limited to ≤30°. In a pay-off tension section, the direction of OPGW after the turning angle should be “C” shaped;
(3) Control of pay-off tension:
Use hydraulic tension pay-off machine and traction machine with tension release device;
Limit pay-off speed ≤0.5 m/s;
(4) Prevent fiber contamination
During the construction and installation of OPGW, attention should be paid to encapsulating the end;
In addition, the fiber loss acceptance test of OPGW should be carried out on site in a timely manner before the OPGW is transported to the site, before the installation, after the installation is completed, and after the fiber splicing is completed, and after the entire line construction is completed.
Send Email 
WhatsApp
