光电复合海缆中光纤与导体温度关系的有限元分析方法

Finite Element Analysis Method for Temperature Relationship Between Conductor and Optical Fiber in Optic-Electric Composite Submarine Cable

根据光电复合海缆中的光纤温度计算导体温度是进行导体温度监测和载流量计算的关键。本文利用有限元法建立了110 kV光电复合海缆的有限元模型,根据IEC 60287标准计算出热载荷,分析了负荷电流、环境温度、土壤与海水的表面传热系数等因素对海缆本体及周围温度分布的影响,建立了海缆导体温度、光纤温度和环境温度的关系式。结果表明,导体温度与光纤温度呈线性关系,光纤温度每升高1℃,导体温度升高1.3℃;相同光纤温度下,环境温度每升高1℃,导体温度下降0.3℃;海缆发热主要耗散于周围1.6m以内的土壤中,土壤与海水表面传热系数对结果的影响可以忽略。根据光纤温度和海水温度,可计算出导体温度,作为海缆导体温度监测和载流量计算的理论依据。

It is essential to calculate the temperature of conductors according to the temperature of optical fibers in optic-electric composite submarine cable for monitoring the temperature of conductors and calculating current-carrying capacity. The finite element model of 110kV optic-electric composited submarine cable is established using finite element method in this paper. The thermal load is calculated according to IEC 60287 standard. The effect to temperature distribution of submarine cable and its periphery are analyzed because of different factors, such as load current, environment temperature and convective heat transfer coefficient between soil and seawater. The relational expression for temperatures of conductor, optical fiber and environment is established. Results indicate that, there is a linear relationship between temperatures of conductor and optical fiber. The temperature of optical fiber will rise 1℃ if the temperature of conductor rise 1.3℃. The temperature of conductor must fall 0.3℃ if environment temperature rise 1℃ with constant temperature of optical fiber. The heat from submarinecable is most spread to around soil of 1.6m diameter. The effect of convective heat transfer coefficient to results can be neglected. The temperature of conductor can be calculated according to temperatures of optical fiber and seawater, which can be regarded as the theoretical basis for monitoring the temperature of conductors and calculating current-carrying capacity.