超高压海底电缆泄漏电流显著，传统的电缆护套感应电流计算方法难以直接应用．针对海南联网工程超高压海底电缆的结构特性和护套接地方式，文中提出了一种计及线芯电流轴向空间分布特性的电缆护套环流理论计算新方法．根据电磁场理论和电路定律推导出了护套－铠装层感应电动势的数学表达式．实测数据和 PSCAD/EMTDC 数值仿真分析结果验证了所提方法的可行性和有效性，为海底电缆理论损耗分析提供了一个实用方法．

Due to the existence of remarkable current leakage in extra- high voltage submarine cables,the traditio-nal methods to calculate the induced current of cable sheath cannot be utilized directly.In this paper,according tothe structure characteristics and grounding mode of the extra- high voltage submarine cables of Hainan Interline Pro-ject,a new method to theoretically calculate the circulating current of sheath,which takes into consideration thespatial axial current distribution of long submarine core,is proposed,and the mathematical formula of the inductiveelectromotive force of sheath- armor layer of the cable is deduced based on the electromagnetic field theory and thecircuit laws.The results of both the on- site test and the PSCAD/EMTDC simulation demonstrate that the proposedmethod is feasible and effective,and that it may serve as an applicable method for the theoretical loss analysis ofsubmarine cables.