A New Grounding Mode for Suppressing Circulating Currents of Submarine Cables

The usually used grounding mode of submarine cables, e.g., the two-ends grounding mode or the multi-spots grounding mode, can often generates significant circulating currents in the metal sheaths and armors, limiting the allowable ampacity of submarine cables. As a solution, this paper proposes a new grounding mode that mitigates the circulating currents and upgrades the allowable ampacity. The detailed structure and requirements of the proposed grounding mode for single-circuit, double-circuit and triple-circuit transmission lines (TL) are firstly described. The numerical calculation model is then constructed to compare the ampacities and circulating currents in different grounding modes. The numerical results show that the proposed grounding mode can dramatically suppress the circulating currents and upgrade the ampacity by approximate 20%, compared with the traditional grounding method. Further research reveals a high terminal voltage performance of this new method. Therefore, the proposed new method can only be used within the certain laying length which is dependent on the insulation grade. This new grounding mode is a promising solution to upgrade the ampacity of submarine cables.