What is OPGW?

An optical ground wire (also known as an OPGW or, in the IEEE standard, an optical fiber composite overhead ground wire) is a type of cable that is used in the construction of electric power transmission and distribution lines. Such cable combines the functions of grounding and communications. An OPGW cable contains a tubular structure with one or more optical fibers in it, surrounded by layers of steel and aluminum wire. The OPGW cable is run between the tops of high-voltage electricity pylons. The conductive part of the cable serves to bond adjacent towers to earth ground, and shields the high-voltage conductors from lightning strikes. The optical fibers within the cable can be used for high-speed transmission of data, either for the electrical utility's own purposes of protection and control of the transmission line, for the utility's own voice and data communication, or may be leased or sold to third parties to serve as a high-speed fiber interconnection between cities.

The optical fiber itself is an insulator and is immune to power transmission line and lightning induction, external electrical noise and cross-talk. Typically OPGW cables contain single-mode optical fibers with low transmission loss, allowing long distance transmission at high speeds. The outer appearance of OPGW is similar to ACSR cable usually used for shield wires.

OPGW fiber optic cable manufacturer introduce OPGW cable

Optical fiber applies the refractive index difference between the core material and its cladding material to accomplish light transmission along optical fiber, which is a major revolution in the history of communication. Fiber optic light weight, small volume, has been widely used in the power system in the substation and dispatching between transport dispatching telephone, remote signal, relay protection, television images of information. In order to improve the stability and reliability of optical fiber and cable, the cable and wire, overhead ground wire and electric cable are developed. OPGW fiber optic cable as a result of metal wire wrapped, so that the cable is more reliable, stable and strong, due to the overhead ground wire and cable composite as one, compared with the use of other means of cable, both to shorten the construction period and save construction costs. In addition, if the OPGW, which is made of aluminum or aluminum alloy wire, is equivalent to a good conductor, can be received to reduce the electric current, reduce the power frequency overvoltage, improve the power line interference and the risk of the communication lines, and other benefits.

Several Different Style of OPGW

Several different styles of OPGW are made. In one type, between 8 and 48 glass optical fibers are placed in a plastic tube. The tube is inserted into a stainless steel, aluminum, or aluminum-coated steel tube, with some slack length of fiber allowed to prevent strain on the glass fibers. The buffer tubes are filled with grease to protect the fiber unit from water and to protect the steel tube from corrosion, the interstices of the cable are filled with grease. The tube is stranded into the cable with aluminum, aluminium alloy or steel strands, similar to an ACSR cable. The steel strands provide strength, and the aluminum strands provide electrical conductivity. For very large fiber counts, up to 144 fibers in one cable, multiple tubes are used.

In other types, an aluminum rod has several spiral grooves around the outside, in which fibers in buffer tubes are laid. The fiber unit is covered with a plastic or steel tape, and the whole surrounded with aluminum and steel strands.

Individual fibers may be in "loose buffer" tubes, where the inside diameter of the tube is greater than the fiber outside diameter, or may be "tight buffered" where the plastic buffer is coated directly on to the glass. Fibers for OPGW are single-mode type

OPGW cable installation guide--Part 1(handling)

Visual inspection  After the delivery of ptical ground wire (hereinafter referred to as OPGW cable), deal with cable appearance inspection, to ensure that it is not damaged in transit. Confirm information on the nameplate of the cable drum, such as drum number, length and diameter of the cable and other details, to make sure the delivered materials are consistant with the orders.

The transportation cable drum should be placed vertically, not permitted to be placed horizontally and piled up. Forklift should handle the cable drum from the side face, and it is definitely prohibited to roll cable drum using the forklift. If crane is applied to handle cable drum, a strong steel axle shaft hole should be used to prevent the chain from destroying cable drum. Every time only one drum should be lifted. If crane is not available, steel sleepers shall be used to hold the rim of the drum to help roll it down slowly. It is not allowed to roll down or drag down the cable drum directly from the vehicle. The OPGW cable drum should be rolled following the rotating direction arrow marked on the drum, Fiber optic cable outlet direction and its opposite. The storage temperature should be controlled in the range of +60oC ~ -40 oC. If the cable drum should be stored for a long period of time before the installation starts, it should be stored in the indoor room to protect the fiber optic cable and cable drum.