Aerial shield wire containing optical fiber
Structure
OPGW is a type of cable that is used in the above distribution and transmission lines.
OPGW cable is made of one or more aluminum or stainless steel tubes containing a certain number of optical fibers and steel wires with aluminum coating in the first layer and steel, aluminum and aluminum alloy wires or a combination of them in the other layers, based on the type of electrical and mechanical characteristics desired has been formed
The number of optical fibers used in the tubes is variable and based on the needs and wishes of the customer, it can start from 1 fiber and reach numbers such as 12, 24, 48 and even higher.
OPGW cables are used at the highest point of transmission line masts.
Single-mode fibers are used in distances of more than one kilometer with high bandwidth and Multi-mode fibers are used in distances of less than one kilometer with lower bandwidths.
OPGW cables are similar in appearance to guard wires (shield wire) or ACSR conductors, and they replace guard wires in existing old lines and are used as a product with two uses in the design of new transmission lines.
Application
This cable is used in transmission lines for two purposes:
- Protection of phase lines containing electric current (overhead transmission conductors) against short circuit currents and instantaneous lightning currents and grounding these currents and transferring them to the ground through transmission towers
2. Transmission of audio and video data using optical fibers
Features
The transmission of optical fibers through aerial transmission masts has many benefits compared to fiber optic cables transmitted through the ground, for example, it is possible to mention the much lower cost of installing each kilometer of these cables in the air compared to ground cables, reducing the damage caused to the cable due to excavations, expanding routes, replacing underground sewage systems, etc.
Also, due to the dual purpose of the OPGW cable, in addition to protecting the phase lines containing electric current against short circuits and lightning currents, the ability of optical fibers can also be used in the transmission of audio and video data, and in places where the transmission of optical fibers through ground cables has a high cost (such as mountainous areas, etc.), the cost of this can be reduced.
Reference standards
All calculations are based on IEEE1138 standard and aluminum coated steel wires are based on ASTM B415 standard in the field of production of OPGW protective wires.