How to prevent lightning damage in optical fiber and cable wiring

Author：hlyb Add Time：2016-05-27 08:28:46

With the development of network, optical fiber, as a medium used to transmit data in generic cabling system, is more and more used by people because of its advantages such as high transmission rate and long distance. As we all know, the optical fiber is non-conductive and can be protected from impulse current. The optical cable also has good protection performance. The metal components in the optical cable have high insulation value to the ground, and the lightning current is not easy to enter the optical cable. However, because the optical cable has a reinforcing core, especially the directly buried optical cable has a armor layer, the optical cable can also be burned or damaged when the optical cable line is struck by lightning.

Today, I'd like to explain in detail the main measures of optical cable lightning protection in the construction of generic cabling project.

Measure 1. Lightning protection for direct optical cable line: ① local grounding mode, the metal parts in the optical cable shall be connected at the joints to keep the reinforcing core, moisture-proof layer and armor layer of the optical cable in the relay section connected. ② According to the provisions of ydj14-91, the moisture-proof layer, armor layer and reinforcing core at the optical cable joint shall be electrically disconnected, and they are not grounded and insulated from the ground, which can avoid the accumulation of induced lightning current in the optical cable and the introduction of lightning current in the ground into the optical cable by the grounding device due to the difference between the lightning protection drainage line and the ground return impedance of optical cable metal components.

Measure 2. For overhead optical cables: overhead suspension cables shall be electrically connected and grounded every 2km. During grounding, they can be directly grounded or grounded through appropriate surge protection devices. In this way, the suspension wire has the protective effect of overhead ground wire.

Measure III. after the optical cable enters the terminal box, the terminal box shall be grounded. After the lightning current enters the metal layer of the optical cable, the grounding of the terminal box can quickly release the lightning current and play a protective role. The directly buried optical cable is adopted, with armor layer and reinforcing core, and the outer sheath is PE (polyethylene) sheath, which can effectively prevent corrosion and rat bite.

Necessary protection shall be implemented for the cable to reduce the damage of the cable as much as possible, so as to reduce the loss to a greater extent.

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How to prevent lightning damage in optical fiber and cable wiring