OPGW cable is Optical Fiber Composite Overhead Ground Wire . The optical fiber is placed in the ground wire of the overhead high-voltage transmission line to form a fiber-optic communication network on the transmission line. This structure has the dual functions of ground and communication, and is generally called OPGW cable. Because the fiber has anti-electromagnetic interference and light weight, it can be installed on the top of the transmission line tower without considering the optimal mounting position and electromagnetic corrosion. Therefore, the OPGW has remarkable characteristics such as high reliability, superior mechanical performance, and low cost. This technique is particularly suitable and economical when laying or replacing existing ground lines.

Optical fiber is a major revolution in the history of communication by utilizing the difference in refractive index between the core and the cladding materials to allow light energy to travel in the optical fiber. The optical fiber cable is light in weight and small in size, and has been adopted by the power system to transmit scheduling telephone, telecontrol signal, relay protection, television image and other information between the substation and the center height. In order to improve the stability and reliability of fiber optic cables, foreign countries have developed a structure in which the phase conductors of the optical cable and the transmission line, the overhead ground wire, and the power cable are integrated. Due to the metal wire wrapped, the OPGW cable makes the cable more reliable, stable and firm. Because of the integration of the overhead ground wire and the optical cable, it can shorten the construction period and save construction costs compared with other optical cables. In addition, if the OPGW is made of aluminum-clad steel wire or aluminum alloy wire, it is equivalent to erecting a good conductor overhead ground wire, which can reduce the potential supply current of the transmission line, reduce the power frequency overvoltage, and improve the power line communication line. The benefits of interference and dangerous effects.

OPGW fiber optic cable is mainly used on 500KV, 220KV, 110KV voltage grade lines. It is affected by factors such as power outage and safety of the line, and is mostly applied on new lines.

The applicable features of the OPGW are:

(1) Lines with a high voltage exceeding 110kv, the span distance is large (generally more than 250M);

(2) It is easy to maintain, easy to solve the problem of line crossing, and its mechanical characteristics can meet the big leap of the line;

(3) The outer layer of OPGW is metal armor, which has no effect on high voltage erosion and degradation;

(4) OPGW must be powered off during construction, and the loss of power outage is large. Therefore, OPGW should be used in the new high-voltage line above 110kv.

(5) In the performance index of OPGW, the larger the short-circuit current, the more it needs to be armored with good conductor. The tensile strength is correspondingly reduced, and in the case of a certain tensile strength, the short-circuit current capacity is increased, and only the cross-sectional area of the metal is increased, thereby causing an increase in cable diameter and cable weight, thus posing a safety problem for the strength of the line tower.