Space Charge Measurements on Flexible Factory Joints for HVDC Extruded Cables

This paper describes the two space charge measurement campaigns on flexible factory joints for HVDC extruded submarine cables carried out in 2024 at Hellenic Cables, Greece, and Jiangsu Zhongtian, China, in the framework of the activities of the IEEE DEIS Study Group on this topic created by the IEEE DEIS Technical Committee “HVDC cable systems (cables, joints and terminations)”. The measurements, done by some members of the study group by means of different PEA cells on flexible factory joints having same geometry, but constructed by two different manufacturers and joint techniques, exhibited a good signal to noise ratio, with clear signal also from the inner semicon. Moreover, the measurement results were consistent with each other and capable of detecting directly or indirectly – especially at higher than room temperature – some effects related to the sloping interface between cable insulation and restored joint insulation, the main signature feature of flexible factory joints. Hence, these measurements seem to indicate that a new IEEE Standard on space charge measurements on flexible factory joints is feasible.