With the development of the network, optical fiber is used as a medium for data transmission in the integrated wiring system. Because of its high transmission rate and long distance, it is more and more widely used. The optical fiber is non-conductive and can be protected from inrush 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, but because the optical cable has a reinforced core, especially direct buried, the optical cable has an armor layer, so when the optical cable line is struck by lightning, the optical cable can also be burnt or damaged. So, how do we prevent lightning damage in fiber optic cable wiring?
The following are the main measures for lightning protection of optical cables and optical fibers in the construction of integrated wiring projects.
Measure 1： Lightning protection for directly buried optical cable lines: ①In-office grounding mode, the metal parts in the optical cable should be connected at the joints, so that the reinforcing core, moisture-proof layer and armor layer of the relay section of the optical cable are kept connected. ②According to the provisions of YDJ14-91, the moisture-proof layer, armor layer and reinforcing core at the optical cable joints should be electrically disconnected, and they are not grounded, and are insulated from the ground, which can avoid the accumulation of induced lightning current in the optical cable. It can avoid that the lightning current in the earth is introduced into the optical cable by the grounding device due to the difference in the impedance of the lightning protection drain wire and the metal component of the optical cable to the ground.
Measure 2： For overhead optical cables: overhead suspension wires should be electrically connected and grounded every 2km. When grounding, it can be grounded directly or through a suitable surge protection device. In this way, the suspension wire has the protective effect of the overhead ground wire.
Measure 3: After the optical cable enters the terminal box, the terminal box should 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 direct-buried optical cable has an armor layer and a reinforced core, and the outer sheath is a PE (polyethylene) sheath, which can effectively prevent corrosion and rat bites.
Post time: 2021-02-24