Description

Designation and usage of OPGW cable

Suspension of optical cable on power transmission towers is one of the most reliable ways to organize communication and transfer of service information. Effective construction of such lines is associated with their laying and installation technology.

Currently, there are several options for suspending optical cable on power lines. These include placing optical fibers in a phase conductor (OPPC), self-supporting optical cables (ADSS), cables wound on a down conductor cable or phase wire (WRAP, GWWOP, GW / PC). But most often an optical cable is built into a down conductor cable. If for the construction of a new overhead line it is necessary to carry out major repairs with the replacement of the down conductor cable, then the use of OPGW will be the most rational option. It is OPGW, due to its highest reliability, that is recommended for organizing backbone communication lines.

OPGW cable design:

Design

The design of the OPGW cable includes an optical module containing optical fibers and an with a single (DAB) or double (DABB) layers of braided wire sheath. The wires are preformed to prevent the cable from unraveling. The cable’s resistance to tensile load is ensured by aluminium clad steel wires (ACS), and resistance to increased short-circuit currents is provided by all-aluminum wire (AA). The required strength and short-circuit current resistance characteristics are achieved by a combination of different numbers of steel and aluminum wires in the sheath.

The OPGW design with a central fiber module was developed first and is widely used. It has certain advantages compared to other types of OPGW, such as easy installation and identification of the optical fiber. The optical fiber lies freely in the tube and has a margin that protects against breakage during a short-term increase in tension or thermal expansion of the cable.

Depending on the calculated maximum tensile load and short-circuit current density, a single-layer (DAB) or double-layer (DABB) OPGW design is calculated. Examples of OPGW cable designs similar to FinMark cables are below:

 Main specifications and parameters for ordering:

When designing an fiber optic communication lines using OPGW, it is necessary to take into account many factors, such as the voltage class of the overhead line, climatic conditions, the design of structural supports and reinforcement, geographical features of the area and much more, so each project is unique. Incorrect selection of OPGW can significantly increase the costs of installation and subsequent maintenance. Therefore, it is extremely important to consider all the parameters of the OPGW.

For the correct selection and ordering of the OPGW, it is necessary to specify its most important parameters:

– The number and type of optical fibers in the cable;

– Tensile force (breaking, maximum permissible, permissible in long term), kN;

– Permissible short-circuit current density, at which the cable temperature will not exceed 200°C, kA2 * sec;

– Weight and dimensions of the cable (diameter, weight of 1 km of cable), necessary for the correct selection of suspension fittings.

In addition, it is necessary to take into account the cross-sectional area of ​​​​aluminum and steel wires, elastic modulus, direct current resistance, operating temperature range.

The “Files” tab contains a table of parameters required when ordering a cable for a project.

It is possible to order OPGW with the corresponding Crosver^TM supplements (clamps, protectors, vibration dampers, couplings, etc.).

The cable is manufactured with Fujikura FutureGuide – LWP optical fiber (compliant with ITU-T G.652.D). At the customer’s request, the optical cable can be manufactured with fibers compliant with ITU-T G.655.