OPGW - OPTICAL GROUND WIRE

OPGW or known as Optical Ground Wire is a type of cable or wire that is used in transmission lines construction. It is also known as optical fiber composite overhead ground wire. It can serve as a grounding wire, shielding wire, and at the same time a cable used for communication purposes. 

OPGW contains a tubular structure with one or more optical fibers in it. It is then surrounded by layers of steel and aluminum wire. It can be compared like an ASCR, except that steel is the one covering the tube with fiber optics inside.

OPGW have the characteristic that there is no effect of high voltage induction on the data being transmitted through the Fibers. Hence this characteristic of the Fiber is taken into advantage to transmit the data along the high power transmission lines.
OPGW cable is run, or installed between the tops of high-voltage electricity pylons, steel, wood, or concrete poles with appropriate fittings and attachments. The conductive part of the cable, in this case the steel serves to bond adjacent towers to earth ground, and shields the high-voltage conductors from lightning strikes. 

Optical fibers within the cable can be used for high-speed transmission of data. The electrical utility could use the fiber optics cable for its SCADA, protection and control system of the transmission line, VOIP, and other communication purposes. In such cases, they could save on the cost of installing additional steel wires serving as ground or shield wires to their lines. They could also lease or sold to third parties to serve as a high-speed fiber optic communication interconnection between cities, and other networks.

In general here are the advantages of using OPGW over conventional methods:

1. Relatively low cost solution to provide Communication and Data backbone trunks.
2. No needto acquire land to lay down the fiber optic cable since Power Transmission Company has right of 
    way for its towers.
3. No digging, trenching, filling etc. is required as the cable is laid high in the air and not underground. This is  
    especially advantageous in hilly, marshy, rocky terrain.
4. The cable is not damaged by human or animal actions as it is out of reach of both of them.
5. The cable is well protected by a bundle of strong steel or aluminum conductors.
6. Wherever the towers have ground wires the new cable can be laid under live conditions i.e. power need 
    not be switched off. Only in the absence of Original Ground Wire, power needs to be switched off to lay 
    the conductors.
7. OPGW provides Power Companies an opportunity to use their towers for other purpose than power 
    transmission. They for a small investment can provide Extremely High Capacity Links to the Telecom 
    sector.
8. As Power Companies have sub-stations all along the route equipment installation space, power supply, 
    security is also available for the communication equipment.
9. Same optical equipment can be used as in case of underground optical fiber cables.
10. The data transmission capacity can be increased as and when needed by just upgrading the optical fiber equipment. The fiber once installed remains the same for its lifetime of around 40 years.

This technical specification covers the structure, mechanical, physical, electrical performance, and optical fiber requirements for Composite Fiber Optic Overhead Ground Wire (OPGW), which is made of aluminum-clad steel wire and stainless steel tube containing optical fiber unit for use as overhead ground wire and telecommunications. Read more...

OPGW is a dual functioning cable performing the duties of a ground wire and also providing a patch for the transmission of voice, video or data signals . The fibers are protected from environmental conditions (lightning, short circuit, loading) to ensure reliability and longevity. The cable is designed to be installed on transmission and distribution lines to carry voice, data and video communications, especially in lighting waveform monitoring system, an observation system for overhead test line, maintenance data information system, power line protection system, power line operation system, and unmanned substation monitoring. Read more...

Optical fibre technology is now regarded as the most powerful and versatile communications medium available. It presented a potentially attractive alternative to radio, provided we could use the 33 kV overhead lines feeding the oil field water supply wells and remote degassing stations system as either communication bearers or as a means of mounting the optical fibre cable systems. Optical fibre systems have been in service for many years and are very reliable as long as due care is exercised during installation of the cable and its jointing. Read more...

Since 1996 CVG EDELCA has built overhead transmission lines employing optical ground wire cable (OPGW) instead of conventional ground wire, and nowadays, it is replacing conventional ground wire by OPGW cable in about 1366 km of overhead transmission live lines. It’s important to review the standards, manufacturers’ recommendations, OPGW cable configurations, selection of materials and acceptance
criteria tests, in order to take them into consideration for the accomplishment of engineering’s specifications of the optical ground wire, and in this way, to assure the data transmission’s quality and electromechanical behavior of the cable, in accordance to optical, physical, electrical and mechanical requirements of the project. In this paper, the process of selection of the OPGW cable based on engineering’s specifications. Read more...

This paper investigates the ability to withstand lightning strikes by OPGW cables used in the ultra-high-voltage (UHV) power transmission lines. With the same annual average thunderstorm days, the amount of the electric charge transferred at 1000 kV is almost an order of magnitude higher than that at 500 kV. It has been found that the best way to improve OPGW performance against lightning strikes is to use an all aluminum-clad steel wire stranded structure, and to increase the diameter of the outer layer wires as much as possible. Read more...

Optical Ground Wire (OPGW or OPTGW) is a dual functioning cable that performs the duties of a ground wire - also known as static wire - while providing a path for the transmission of voice, video or data signals by incorporating optical fibers into the design of the cable. AFL Telecommunications is the world's leading supplier of OPGW. Our OPGW is ideal for voice, data and video communications and integrates easily into new and established high voltage systems. OPGW is placed at the highest point on power utility structures, allowing for fast, cost-effective installations and extraordinary reliability. Read more...

Overhead optical fibre cable systems have become a key factor in telecommunications networks used by operators and power utilities. Due to the fact that no civil works are required and the rights of way have already been established, it is possible to minimize costs and, most importantly, the time required to begin network operation. Read more...

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