252 / 2022-03-14 21:00:46

Nonmagnetic armor wire effect on induced current for subsea cables

Subsea cables;,armor current;,finite element model;,relative permeability.

Submarine power cables have been widely used for energy link across seas. Solid grounding at both ends is a common design which leads to highly induced current in the armor. To reduce the induced current, nonmagnetic copper wires are used by manufactures to replace the magnetic steel wires. However, the replacement effect is seldomly studied in detail. This paper proposes a “field-circuit” analysis approach to solve the issue.Firstly, a finite-element model for 220 kV subsea cable is established. The steel armor wires are replaced with copper wires to study the induced current. Secondly, a complete subsea cable system is setup in ATP-EMTP software. Different armor designs are applied in the model with equivalent permeability derived from finite-element model.It has been shown that the nonmagnetic copper wire can reduce the equivalent permeability of the armor, leading to lower induced current. Meanwhile the current in lead sheath is also affected.To replace subsea power cable steel armor wire with nonmagnetic copper wire can reduce the induced current in armor. Detailed engineering calculation should be performed to derive the accurate estimation for the effect, especially for lead sheath.