计及沉积物渗透性的捆绑式高压直流海底电缆载流量评估模型

A Model for Estimating the Ampacity of Bundled HVDC Submarine Cables Considering Sediment Permeability

准确评估捆绑式敷设海底电缆的温度场与载流量,对于保障其安全稳定运行,同时提高运行效率、降低建设成本非常有价值。采用现有的解析法计算捆绑式海底电缆载流量忽略了诸多影响因素。为此,该文分析直流电缆结构和海底运行环境,在研究多孔介质固相和液相散热机理的基础上,提出一种计及海底沉积物渗透性的海底电缆电磁–热–流多物理耦合计算模型,提高对电缆温度场和载流量评估的准确性。对捆绑式敷设的±160k V双极直流海底电缆进行算例分析,考虑埋设和铺设2种情况,通过云图可视化展示了多场耦合后的散热机制;在典型沉积物渗透率的取值范围内计算了电缆的温度场和载流量,当渗透率大于10d后,渗流问题对于埋设的电缆载流量计算不可忽略。传统的热传导模型和IEC解析法是目前工程上常用的海缆载流量评估方法,在所提模型中代入不同的海底沉积物渗透性参数可与之对应,所得结果的最大相对误差不超过4%,验证了该模型的有效性。该模型可以设置任意渗透性参数来模拟实际海底沉积物的情况,因此在不同应用环境中对载流量的评估更为准确。

Accurate estimate of the temperature field and ampacity of the bundled submarine cable is of great significance to ensure its safe and stable operation,improve operating efficiency,and reduce construction costs.In view of the neglect factors of the current analytical method for calculating strap-down submarine cables,this paper analyzed the structure of the DC cable and the submarine operating environment.Based on studying the heat dissipation mechanism of porous media in solid phase and liquid phase,a multi-physics coupling submarine cable calculation model that considers the permeability of submarine sediments was proposed aiming at improving the accuracy of the cable temperature field and ampacity evaluation.In this paper,a case study of 160 kV bipolar DC submarine cable with bipolar strap-lay was presented.Considering the two situations of burying and laying,the heat dissipation mechanism after multi-field coupling was visualized by nephogram visualization;the temperature field and ampacity of the cable were calculated in the range of typical sediment permeability and compared with the analytical method.When the permeability was more than 10 d,the porosity permeating flow could not be ignored for the calculation of the ampacity of buried cables.The traditional heat conduction model and IEC analytical method were commonly used to evaluate the ampacity of submarine cables in practical engineering.Different permeability parameters of seabed sediments were brought into the model in this paper,and the maximum relative error of the results was less than 4%,which verified the effectiveness of the model in this paper.The model proposed in this paper can set any permeability parameters to simulate the actual seabed sediments,so the calculation of ampacity is more accurate in different application environments.