Cause of OPGW cable joint box failure

There was a communication failure in the OPGW cable joint box of a 500kV Line. When the joint box was opened, a large amount of anti-corrosion grease overflowed on the surface of the optical cable protective tube, and there was ice slag at the fixed place between the aluminum clad steel on the outer layer of the optical cable and the splice closure. According to the records, the optical cable joint box had failed a year ago and was replaced. Through the analysis of the faulty connector box, the possible reasons for the failure of the connector box are: the sealing failure of the connector box causes water or moisture to enter the connector box, which affects the attenuation of optical fiber; The construction process of OPGW joint box, the joint box or OPGW optical cable is damaged, which affects the performance of the joint box or OPGW; Due to local climatic conditions and other reasons, the fixed position of OPGW optical cable is frozen and crushed.

Joint gold seal failure

During operation, sealing failure is the most common problem of the joint box. Sealing failure will cause moisture to enter the joint box, resulting in a central aluminum tube structure with a relatively large diameter. Therefore, it is easy to be mistaken for the aluminum tube of the optical unit to be cut outside the joint box. In addition, it is easy to damage the aluminum tube of the optical fiber unit during stripping, which will lead to rainwater between the aluminum tube and the cable core, thus affecting the optical fiber.

Causes of climatic conditions

The air in the place where the joint box fails is humid, especially in winter when the humidity is high, it is easy to deposit moist air (commonly known as dew drops) between the outer aluminum clad steel gaps at the fixed place of the optical cable. When the temperature drops sharply to 0 ℃, the dew drops begin to form ice, resulting in the increase of the volume of the optical cable at the fixed place of the OPGW optical cable, resulting in - a squeezing force towards the inner direction of the cable core. In addition, the material of the optical fiber protection tube is plastic hose, which is very easy to be squeezed, As a result, the attenuation of optical fiber core increases or is interrupted. A large amount of anti-corrosion ointment overflowed from the optical fiber protection tube in the faulty joint box, indicating that the optical fiber protection tube was squeezed. It was precisely because of the local humid climate conditions that the water vapor entered the optical fiber unit and condensed. At low temperature, the water vapor froze in the aluminum tube optical fiber unit, causing the extrusion of the optical fiber protection tube.