远距离光缆通信线路的防雷研究

为预防雷电入侵光缆线路并造成危害,从雷电的形成和通信光缆遭遇雷击的机理,得出在电阻率均匀的土壤中雷击点周围会形成一个等电位的半球体,半球体外地电位呈漏斗形下降的结论,且给出了相应的计算公式,并通过典型雷击示例的分析得到验证。结合光缆线路遭遇雷击的规律,提出了对地电位悬浮式接续、消弧线、地下防雷线、架空防雷线等有效的通信光缆线路防雷措施以及工程勘测设计中应该考虑的防雷问题。这些措施在实际应用中有效减少光缆遭遇雷击的几率。

Lightning Protection Research of Long-distance Optical Fiber Communication Line

Based on the mechanism about the formation of thunder and lightning and lightning striking on optical fiber communication line, how to prevent the harm on optical fiber line caused by the invasion of thunder and lightning is investigated. Conclusion is drawn that a hemisphere of equal potential is formed around the spot of lightning striking and the ground potential comes down rapidly outside the hemisphere in the soil with homogeneous resistivity. Corresponding calculation formula is given including the calculation of the potential for a small hemisphere inside and outside, the calculation of safe distance between optical cable and the spot of lightning struck, and the calculation of forecasting times of lightning struck on optical cable. The formulas given in the paper can be referred to and applied in design. The conclusion is proved by typical examples of lighting striking. Combined with the rule about lightning striking on optical fiber line, several measures about lightning protection of optical fiber communication line and lightning protection in engineering survey and design are put forward such as floating ground, arc suppression coil, the lightning protection of underground lines, the lightning protection of overhead line, these measures can decrease or reduce effectively the probability of lightning striking on optical fiber line.