Electrical Characterisation of Solid-Liquid Composite Insulation Systems used in Subsea Connectors

Subsea power delivery is essential for not only oil and gas recovery but also for developing off-shore renewable technologies. High voltage cable connectors are often required to mate/demate at the subsea environment. Mineral oil has been used as the dielectric liquid in the subsea cable connectors. It, however, poses a risk to contaminate the sea water in case of unexpected leakage. Therefore, it is motivated to use alternative dielectric liquids with low environmental impact. Synthetic ester is such an alternative candidate due to its much superior biodegradability. In addition, the synthetic ester can provide better fire safety guarantee due to its high fire/flash point, which is about double of that of mineral oils.

This PhD programme aims to investigate the electrical characteristics of the cable connector insulation materials including Silicone-PEEK-Ester in terms of breakdown strength of the bulk insulation and creepage discharge/surface tracking phenomena along the solid-liquid interface. The project will start from an in-depth literature review and then followed by designing the suitable experimental setup. Breakdown strength of the solid insulation materials will be tested at different temperatures. Creepage discharge and surface tracking along the solid-liquid interface will be studied from initiation, propagation and till breakdown stages. Both short-term and long-term stresses will be considered. The study will promote applications of greener and safer subsea high voltage cable connector.