利用光纤应变判断光电复合海缆锚害程度的有限元分析法

Finite Element Analysis for Judging Anchor Damage Degree of Photoelectric Composite Submarine Cable by Optical Fiber Strain

锚害占海缆机械故障的80%以上,不同程度的锚害会导致海缆发生漏电、接地、短路和断缆事故,及时发现锚害并判断锚害程度十分重要。本文提出了利用光电复合海缆中光纤的应变判断海缆锚害程度的有限元分析法。建立了110k V光电复合海缆的有限元模型,对海缆锚害过程进行了仿真和分析,建立了海缆锚害过程中铠装层应力和光纤应变的分段时间函数,对锚害程度进行了分级,并用海缆模型试验验证了仿真结果。结果表明,海缆锚害程度的加剧导致光纤应变的增加,海缆锚害过程可用5个分段函数表示,锚害程度可分为三级,分别对应0.12%、0.35%和1.1%的光纤应变,可利用分布式光纤传感技术测量的光纤应变判断海缆的锚害程度。

Anchor damage accounted for more than 80% of the submarine cable mechanical failure. Different damage degrees can lead to leakage, ground, short circuit and broken fault. It is very important to find anchor damage and judge the damage degree. The finite element analysis method is proposed to judge the anchor damage by strain of optical fiber composite in submarine cable. The finite element model of a 110 k V photoelectric composite submarine cable is established. The process of anchor damage to submarine cable is simulated and analyzed. The segmented time function of armored layer stress and fiber strain in anchor damage process is provided. The anchor damage degree is graded. The simulation results are verified by submarine cable model experiment. Results indicate that the aggravation of anchor damage can lead to increase of optical fiber strain. The anchor damage process can be represented by five piecewise functions and damage degree can be divided to three grades which according to three values of optical fiber strain as 0.12%, 0.35% and 1.1%. The anchor damage degree to submarine cable can be judged by optical fiber strain measured by distributed optical fiber sensing technology.