交流500 kV交联聚乙烯绝缘海缆设计关键问题

Key Problems of Design for AC 500 kV Cross-linked Polyethylene Insulation Submarine Cable

为实现世界首条500 kV交联聚乙烯海缆的研制,对海缆交流电阻设计、绝缘缓冲层的选择、软接头电场设计等关键问题进行了分析,分析结果表明:海缆敷设后各相距离较远,临近效应对海缆交流电阻的影响可以忽略;通过绝缘线芯的热膨胀试验可以确定绝缘缓冲层的厚度;控制软接头恢复绝缘与本体绝缘之间交界面电场是对海缆软接头进行电场设计的关键;基于海缆金属护套、铠装层上的感应电压计算是进行确定中间接地位置的重要基础。

In order to develop world＇s first 500 kV cross-linked polyethylene insulation submarine cable,the critical technology during design are summarized such as the design of the AC resistance,the selection of insulation buffer layer and the electric field design of flexible joint. Owning to the distance among the different phases submarine cable conductors,the neighbor effect on the AC resistance could be neglected. The buffer layer could be selected by thermal expansion test of insulated cable conductor. The control of the electric field at the interface between the flexible joint and the cable is the key to design the electric field inner submarine cable flexible joint. Calculation of induced voltage on the cable metal sheath and armor layer is the important basis to confirm the position of the middle ground.