Single End Bonding of submarine 3-core cables – Qualification Testing

The proposed SPB system introduces two key innovations: a semi-conductive (SC) PE sheath with enhanced electrical conductivity, and a helically applied metallic electrode tape outside the SC PE sheath. These features enable efficient transverse current transfer between metallic sheaths in the current transfer zone (CTZ) near the landfall-offshore transition point, minimizing voltage build-up and power dissipation. Extensive material development and testing confirmed that the SC PE sheath maintains both high conductivity and mechanical integrity, while the electrode tape demonstrates excellent corrosion resistance and longevity in saline environments. A comprehensive qualification program was conducted, including type tests according to

CIGRE TB490 and IEC 62067, as well as electrical measurements on both short and long (67 m) full-scale cable samples submerged in saline water for validation of the developed calculation model. The results confirmed that the SPB system meets all electrical and mechanical requirements, with measured values for sheath voltages and currents closely matching model predictions. No significant temperature rise or thermal degradation was observed during high-current operation, and the system demonstrated robust performance under simulated fault conditions.

The study concludes that single-point bonding technology is now considered qualified for 3core submarine cables. The SPB system offers a viable solution for increasing ampacity and reducing losses in thermally constrained landfall sections of submarine cable routes. The demonstrated manufacturability, successful type testing and validation of calculation models establish SPB as a practical and reliable option for future cable systems.