A novel grounding mode for enhancing current rating of AC submarine cables

Due to the deficiency in using the cross-bonded grounding mode, a large circulating current is usually induced in the metal sheaths and armors, reducing the permissible current rating of submarine cables. To address this issue, this paper proposes a novel grounding mode to suppress these circulating currents and enhance the permissible current rating within the voltage limits of metal sheaths and armors. To achieve the best performance of the novel grounding mode, the optimal grounding impedances are given. Theoretical analyses indicate that for general submarine cables, the novel grounding mode can suppress the circulating currents within the voltage limits compared with the two-ends grounding mode, and can reduce the short-circuit terminal voltage of metal sheaths and armors compared with the non-interlinked version of the proposed mode. The numerical results further validate the better comprehensive performances of the novel grounding mode in reducing the power loss and short-circuit overvoltage.