典型敷设环境下超高压交流XLPE海底电缆载流量分析

Ampacity analysis of extra-high voltage XLPE submarinecable in typical layout environments

超高压海底电缆线路跨度大,运行环境复杂多变,不同敷设环境下海底电缆的输送容量也不尽相同,有必要对典型敷设环境下超高压海缆输送载流量进行具体分析。文中基于IEC 60287建立考虑外界敷设环境影响下的500 kV交流交联聚乙烯(XLPE)超高压海底电缆稳态热路模型,分析不同敷设段、不同敷设方式、不同环境温度以及不同埋设深度对海缆载流量的影响规律进行分析,并建立超高压海底电缆磁-热-流多物理场耦合有限元仿真模型对稳态热路模型计算结果进行验证。结果表明:海缆登陆段为整条线路的载流量瓶颈段,当登陆段海缆采用管道敷设时,其载流量要比采用土壤直埋敷设时的载流量降低约150 A,海缆载流量随着外界温度的升高以及土壤埋设深度的增加而逐渐降低。有限元仿真结果验证了文中所建立的热路模型计算结果的准确性。

The layout environments of the extra-high voltage(EHV)submarine cable are complex and changeable,and the ampacity of the EHV submarine cable varies under different layout environments.Therefore,it is essential to analyze the ampacity of the EHV submarine cable in typical layout environments.In this paper,a steady-state thermal circuit model for the alternating current(AC)500 kV cross linked polyethylene(XLPE)EHV submarine cable based on IEC 60287 standard is established,and the influences of layout sections,layout methods,environment temperatures,and layout depths on the ampacity of EHV submarine cable are studied.The results of the steady-state thermal circuit model are verified by a multi-physical field finite element model.It is found that the landing section of the submarine cable is the bottleneck section of ampacity of the whole line.When the submarine cable in the landing section is laid by pipeline method,the ampacity is about 150 A lower than that by the direct burial layout method.The ampacity of submarine cable decreases with the environment temperature and the layout depth.The finite element calculation results verify the accuracy of the results of the steady-state thermal circuit model.